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Abstract
Potato is an important food and cash crop in Eastern Ethiopia; however, its productivity is low for a number of constraints. Shortage of quality planting material and poor tuber sprouting due to long dormancy period of improved varieties at planting are two of the factors known to affect production cycle and productivity of the crop in Eastern Ethiopia. Two separate experiments were conducted from November 2013 to June 2014, to assess the effect of Gibberellic acid and storage condition on seed tuber dormancy breakage of two potato varieties. The treatments in the first experiment consisted of two potato varieties (‘Bubu’ and ‘Bate’) and three levels of Gibberellic acid (GA3) (0, 10, and 20 ppm) kept under three storage methods: in diffused light store (DLS), in pit, and in farmyard manure (FYM) heap. The experiment was laid out as a randomised complete design with four replications and conducted in the horticulture laboratory of Haramaya University. The second experiment consisted of the same treatments laid out in the field to study the effects of the treatments on the subsequent growth, yield, and yield-related traits. The experiment was laid out in a randomised complete block design with three replications and conducted on a farmer’s field. The results of the experiments showed that genotypes, exogenous application of GA3, and storage conditions, as well as the interaction between them, significantly affected seed tuber dormancy period, sprouting characteristics, and subsequent tuber yield. Dormancy period, sprouting percent, sprout length, length of lateral axillary sprouts, and sprout vigour were significantly affected by the treatments. However, parameters such as days to 50% emergence, days to 50% flowering, and number and weight of very small and small tubers showed highest values for seed tubers, either treated with GA3 or not, and stored under FYM heap and pit storage conditions when compared with tuber treated and stored in DLS. In general, the study indicated that the interaction between genotypes, exogenous application of GA3, and storage conditions resulted in early dormancy termination, early emergence of shoots, and high marketable tuber yield.
Gemeda MustefaTheme 3: Effect of dormancy-breaking methods on seed tuber sprouting and subs...
Theme 3: Effect of dormancy-breaking methods on seed tuber sprouting and subs...African Potato Association (APA)
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Abstract
Potato is an important food and cash crop in Eastern Ethiopia; however, its productivity is low for a number of constraints. Shortage of quality planting material and poor tuber sprouting due to long dormancy period of improved varieties at planting are two of the factors known to affect production cycle and productivity of the crop in Eastern Ethiopia. Two separate experiments were conducted from November 2013 to June 2014, to assess the effect of Gibberellic acid and storage condition on seed tuber dormancy breakage of two potato varieties. The treatments in the first experiment consisted of two potato varieties (‘Bubu’ and ‘Bate’) and three levels of Gibberellic acid (GA3) (0, 10, and 20 ppm) kept under three storage methods: in diffused light store (DLS), in pit, and in farmyard manure (FYM) heap. The experiment was laid out as a randomised complete design with four replications and conducted in the horticulture laboratory of Haramaya University. The second experiment consisted of the same treatments laid out in the field to study the effects of the treatments on the subsequent growth, yield, and yield-related traits. The experiment was laid out in a randomised complete block design with three replications and conducted on a farmer’s field. The results of the experiments showed that genotypes, exogenous application of GA3, and storage conditions, as well as the interaction between them, significantly affected seed tuber dormancy period, sprouting characteristics, and subsequent tuber yield. Dormancy period, sprouting percent, sprout length, length of lateral axillary sprouts, and sprout vigour were significantly affected by the treatments. However, parameters such as days to 50% emergence, days to 50% flowering, and number and weight of very small and small tubers showed highest values for seed tubers, either treated with GA3 or not, and stored under FYM heap and pit storage conditions when compared with tuber treated and stored in DLS. In general, the study indicated that the interaction between genotypes, exogenous application of GA3, and storage conditions resulted in early dormancy termination, early emergence of shoots, and high marketable tuber yield.
Gemeda MustefaTheme 3: Effect of dormancy-breaking methods on seed tuber sprouting and subs...
Theme 3: Effect of dormancy-breaking methods on seed tuber sprouting and subs...African Potato Association (APA)
Abstract
In Tigray, Ethiopia, maize is the principal cereal crop grown both under rain-fed and irrigation schemes. Potatoes have been grown for decades as a major vegetable crop and for income generation. And although both crops are grown mainly in mono-cropping, some farmers practiced intercropping without distinctive plant arrangement. Moreover, no research work has been conducted on the productivity of the system in the region. The objective of our study was to examine the potential of intercropping of maize–potato within a cereal cropping system to increase food production and income of rural households. To investigate the best production niches and highest land use efficiency for the productivity of maize–potato intercropping. The experiment was conducted during the 2012 cropping season at Hawzen Bureau of Agriculture nursery site, and consisted of three combination ratios (2:1, 1:1, 1:2) in maize–potato row arrangements and maize–potato monocropping. The experiment was laid out in a randomised complete block design with three replications. ‘Melekasa II’ and ‘Gera’ varieties were used for maize and potato, respectively. Both crops were planted simultaneously in rows 75 cm apart with 30-cm intra-row spacing. Fertilisers were applied at rates of 50 kg urea and 100 kg DAP/ha for maize and 195 kg DAP/ha and 165 kg/ha urea for potato. Data were subjected to analysis of variance. Mean comparison was performed using Duncan's new multiple range test, and land equivalent ratio (LER) index was used to evaluate intercrop efficiencies with respect to single crops. The analysis of variance showed significant differences on plant height and yield of maize in all treatments (p>0.01). The highest mean plant height of 238 cm was recorded from maize only and the lowest height of 198 cm from 1:1 cropping ratio. The highest grain yield of 4.7 t/ha was obtained from single crop followed by two rows of maize intercropped with one row of potato (4.4 t/ha). Partial LER showed a significant difference among treatments where two rows of maize/one row of potato gave 94% of the single crop. Highest tuber yield (34.4 t/ha) was obtained from potato only, whilst the lowest (14.09 t/ha) potato yield was obtained from two rows of maize/one row of potato. Results revealed that both maize and potato are compatible for intercropping under different cropping intensities. Partial LERs for potato and maize grown in the intercropping systems are less than unity. The highest partial LER of potato (0.80) and the least (0.41) were obtained from 1 row of maize to 2 of potatoes and 2 rows of maize to 1 of potato, respectively. Two rows of maize to 1 of potato gave the highest maize equivalence and the lowest potato equivalence. Partial equivalence of maize increased as equivalence of potato decreased. The current inter-cropping systems implied that farmers could benefit by growing the companion crops with different cropping intensity in the dry lands of Tigray.
Beyenesh Z. KidaneMonday 3: Maize and potato intercropping: a technology to increase productivi...
Monday 3: Maize and potato intercropping: a technology to increase productivi...African Potato Association (APA)
Abstract
Farmers who produce sweetpotato in Ethiopia save planting material on farm during the long dry months. Water stress and virus and weevil pressure during this period are the main causes of both the loss of farm-saved sweetpotato planting material and the country’s shortage of planting material. In other African countries, “Triple S” is a newly emerging root-based sweetpotato planting material conservation technique that has enabled small-scale farmers to conserve planting material for up to 3 months in dry periods. The dry months in Ethiopia last 3–5 months in the Southern Nations, Nationalities, and Peoples' Region (SNNPR) and 7–9 months in Tigray region, where direct adoption of the original Triple S technique is not feasible. Therefore, the aim of this study is to modify and test root-based sweetpotato planting material conservation methods appropriate for Ethiopia. In SNNPR, 12 farmer research groups compared Triple S techniques with shade conservation and conventional methods. In Tigray, an on-station trial was conducted to test the sprouting potential of different sizes (small, medium, and large) of roots stored in sand-filled containers after different storage periods. Results show that roots stored in sand-filled containers start sprouting 4–6 weeks after first being stored. On average, 82% of roots stored could sprout after 3, 4, and 5 months and be transplanted for vine multiplication. Forty-five days after transplanting, each root gave above-ground fresh vine yields of 883 g, 656 g, 680 g, and 615 g in Dorebafana, Kedidagamela, Humbo, and Mirab-Abaya woredas, respectively. Storing only 40 roots using Triple S can produce enough planting material to plant 400 m2 of land. In addition, the quality of vine produced through Triple S is better than that from farm-saved planting material in terms of being free of viruses and weevil. In our separate experiments to adapt Triple S for 8–9 months during the dry period in Tigray, 61%, 62%, and 52% of roots sprouted after 6 months of storage. The present study confirmed the potential of Triple S to increase the security of sweetpotato planting material in drought-prone areas in Ethiopia. Additional studies are being conducted to refine factors such as age and size of roots and storage and transplanting time.
Mihiretu CherinetTheme 3: Testing “Triple S” in a new context: sweetpotato planting material c...
Theme 3: Testing “Triple S” in a new context: sweetpotato planting material c...African Potato Association (APA)
Abstract
Sweetpotato produces substantial yields of both roots and vines for food and fodder at the same time on the same plot of land, making them attractive food–feed crops. Vine harvesting from sweetpotato gardens to be used either as fresh fodder or processed into silage, however, might compromise the root yield at harvest. A study was conducted to determine the effect of vine harvesting (de-topping) on root and vine yield of different sweetpotato varieties in Uganda. Experiments were set up on-station on Uganda Martyrs University farm and on-farm in Kamuli and Masaka districts in 2015 and 2016. The experiments were established with four sweetpotato varieties (‘NASPOT 11’, ‘NASPOT 12 O’, ‘NASPOT 13 O’, and a local variety) laid out in a randomised complete block design with four replicates. Data were collected on fresh root and vine weight, dry vine weight at 2 and 4 months after planting, incidence and severity of sweetpotato virus disease (SPVD), Alternaria blight, and weevil damage at harvesting. Data were analysed using Genstat (12th ed.). ‘NASPOT 11’ had the highest yield, followed by the local variety. There was a significant difference in the root yields of the different varieties for the de-topped crop and the non-de-topped crop. The non-de-topped local variety yielded 8.0 t/ha compared with the de-topped (3.4 t/ha), whereas the non-de-topped ‘NASPOT 13 O’ yielded 6.3 t/ha compared with the de-topped (4.6 t/ha). ‘NASPOT 11’ and ‘NASPOT 12 O’ were generally less affected by de-topping. De-topping at 85 days after planting results in root yield loss; all varieties had moderate resistance to SPVD and Alternaria blight. ‘NASPOT 11’ and ‘NASPOT 12 O’ are responding better to vine harvesting and are potential candidates for making sweetpotato silage.
Elizabeth AkirorTheme 3: Effect of vine harvesting on root and vine yield of different sweetp...
Theme 3: Effect of vine harvesting on root and vine yield of different sweetp...African Potato Association (APA)
Abstract
In Lake Zone, Tanzania, the Sweetpotato Action for Security and Health in Africa Marando Bora project trained farmers to become specialised multipliers to produce and distribute sweetpotato seed. The objectives of the case study were to analyse (1) how farmers and trained multipliers characterised and managed quality in sweetpotato planting material; (2) changes in skills and practices as multiplication became a specialised task; and (3) what other transactions were happening as planting material was exchanged. The study used mixed methods to investigate the sweetpotato seed system as a social and technical configuration and the processes and interactions within it. A formal survey of 88 trained decentralised vine multipliers (DVMs) was conducted in March 2013. Detailed observations and semi-structured interviews were also carried out with 21 farmers and a sub-group of the DVMs. The survey results showed that 70% of DVMs were multiplying vines 9 months after the project finished; 34% were using close spacing in beds; 61% were using conventional plant spacing on ridges for roots and vines; and 5% were using both multiplication beds and ridges. Further, 97% of DVMs irrigated from wells, springs, lake, river, or dam water; 34% used pumps. During the life of the project, 89% of DVMs used fertilizer, and 26% continued to use it after the project finished. The in-depth interviews showed that farmers selected planting material not only on the basis of plant health, but also used cues to plant vigour. The use of own-saved seed involved a complex performance of managing seed and root production across different agro-ecologies according to inter- and intra-season characteristics. As the vine multiplication cycle became a specialised activity, vines were treated differently, depending on whether they were to be used for high root production or high vine production. The resilience and viability of the existing seed systems depended not only on individual knowledge and skills, but also management practices across agro-ecologies and negotiating social settlements at community level. As specialisation of seed production developed, the multiplication and root production cycles were separated and tasks became segregated. New knowledge and skills were formed in different ways; the trained multipliers adapted the new techniques into the existing system of shifting vine conservation and root production between different ecologies. Interventions aimed at building the capacity of specialised vine multipliers and scaling-up seed interventions should consider the implications of skills-building and segregation of tasks in the broader context of society choice of technologies and agrarian change.
Margaret A. McEwanTheme 3: Specialised sweetpotato vine multiplication in Lake Zone, Tanzania: ...
Theme 3: Specialised sweetpotato vine multiplication in Lake Zone, Tanzania: ...African Potato Association (APA)
Abstract
Limited accessibility to high-quality potato seed is a perennial problem for many farmers, and can be attributed partly to inefficiencies at various stages of the seed production system. In soilless culture like aeroponics, nutrient optimisation is the most critical factor to produce high-quality, high-yielding clean potato seed. Each crop has an optimum nutritional requirement; even each potato cultivar may require a specific nutrient solution in an aeroponics unit. A nutrient optimisation experiment was conducted at the Holetta Agricultural Research Center to study the effect of different nutrient composition levels on the physical quality and yield of potato mini-tubers (here, variety ‘Belete’). There were four treatments, each with different compositions of greenhouse-grade macro-nutrients, measured in grams for the preparation of 500-L volume of nutrient solution: A = 118 gm CaNO3, 252 gm KNO3, 68 gm KH2PO4, and 100 gm MgSO4; B = 59 gm CaNO3,126 gm KNO3, 68 gm KH2PO4, and 100 gm MgSO4; C = 118 gm CaNO3, 252 gm KNO3, 68 gm KH2PO4, and 100 gm MgSO4 until flowering and reduced by half after flowering; and D = 118 gm CaNO3, 252 gm KNO3, 136 gm KH2PO4, and 100 gm MgSO4. The same level of micro-nutrients was used for all treatments. Acclimatized plantlets were planted in alternative or sequential manner from one another in a completely randomised design with three replicates. The results showed that each treatment varied in nutrient consumption rate throughout the life span of the crop. Treatment A consumed the highest amount of nutrient (3.29 kg, 28%), treatments B and D consumed the same amount (3.1 kg, 27%), and treatment C consumed the smallest amount (2.0 kg, 17%). Root length was significantly affected by nutrient solution. Nutrient solution C produced the longest root (300.8 cm), whereas nutrient solutions A, B, and D produced root lengths of 135.5, 198.3, and 174.4 cm, respectively. Plant height was not significantly affected by nutrient treatments. Small tubers (<8>12 gm) were significantly affected by nutrient treatments both in number and weight. The maximum tuber number was obtained from treatment B, followed by C and D. On the basis of these results, different nutrient solution concentrations significantly affected root length and tuber size both in number and weight. Therefore, the experiment indicated that treatment B represents the optimum nutrient concentration rate to use in an aeroponics mini-tuber production system under Holetta conditions.
Lemma Tessema GebrehannaMonday 3: Determination of nutrient solutions for potato (Solanum tuberosum L...
Monday 3: Determination of nutrient solutions for potato (Solanum tuberosum L...African Potato Association (APA)
Abstract
Pathogen-tested sweetpotato planting material is shown to provide a significant boost in yield and quality in the sweetpotato seed systems and value chains. In the absence of pathogen-tested planting material, negative selection has been shown to be effective in some cultivars and locations as well. Protective net tunnels allow decentralised vine multipliers to maintain and multiply limited quantities of clean planting material. Commercial demand for sweetpotato planting material is likely to be sustained if seed producers are able to provide evidence of the superiority of their product to their customers. The objective of this study was to evaluate the effects of net tunnel source and of pathogen-tested planting material on yield and health status (sweetpotato virus disease [SPVD] and weevil incidence) of crop. Studies were conducted in 2015, at locations in Ghana that varied with regard to SPVD and weevil pressure. Four varieties were used with pathogen-tested planting materials—‘Apomuden’, ‘Dadanyuie’, ‘Bohye’, and ‘Ligri’—and multiplied in net tunnels. ‘Apparently’ healthy (field-derived, negatively selected) material of the same varieties were also multiplied in adjacent field plots at one location in northern Ghana. For ‘Apomuden’, the apparently healthy planting material was multiplied in both net tunnel and open field at the same location. The trials were conducted at three sites in northern Ghana: Nyankpala, Navrongo, and Wa. At each site, 8 treatment combinations (4 varieties and 2 sources of planting material) were arranged in a trial design with three replicates. The 4 x 5.1 m plots were planted to 17 vine cuttings per row, spacing 0.30 m within rows and 1 m between rows, and no additional irrigation. Weeding, reshaping, and vine lifting were done at all locations. NPK (15:15:15) was applied at Navrongo and Wa, 4 weeks after planting, as recommended, due to natural poor soil fertility. Data were analysed using Genstat (12th edition). There were highly significant differences among varieties and trial sites for plant establishment, foliage yield, root yield, weevil damage, and SPVD rating; but source of planting material was not found to be significant. For SPVD, net tunnel source is better than open field (p<0.01).><0.04). The results indicate that apparently healthy planting material was as effective as pathogen-tested planting material. Net tunnels may have a distinct advantage for maintaining and multiplying planting material to produce healthy sweetpotato crops.
Putri E. AbidinMonday 3: Comparative studies on sources of sweetpotato planting material for...
Monday 3: Comparative studies on sources of sweetpotato planting material for...African Potato Association (APA)
Abstract
Production potential of sweetpotato is not realised in most regions experiencing dry spells after the growing season in sub-Saharan Africa due to lack of planting material at the beginning of the rainy season. Identifying cultivars with ability to survive a 4- to 7-month dry spell is worthwhile in improving the sweetpotato seed system in these regions. The objective of the study was to estimate survival of vines under drought stress in a collection of sweetpotato clones. Three treatments (different harvesting times set as 5, 9, and 11 months after planting) were established at Umbeluzi, Nwallate, and Gurué in February 2015. In each treatment, 37 sweetpotato clones (18 released varieties, 8 landraces, 2 check clones, and 9 foreign introductions) were evaluated in a randomised complete block design with two replications. Data collected on storage root and vine yield, virus infection, vine length, and number of sprouts were subjected to analysis of variance using SAS 1996. Clone performance varied significantly within treatments. There was a significant drop in vine yield as the harvesting period increased from 5 months at all sites. Introduced variety ‘Resisto’ had long stems but no vines remaining after 9 months at all sites. Length and thickness of vine in a clone could be traits responsible for drought tolerance in sweetpotato. Spatial soil differences affected survival of vines. Most clones could not survive after 7 months at Gurué where the soils are lighter in texture and have low capacity to retain water. At Gurué, the inability to survive for long periods was exacerbated by virus infection. Gurué is an important site for virus screening in the breeding programme. A 6–8% significant increase of storage root yield between the 5 and 9 months’ harvest was recorded at Umbeluzi and Nwallate, respectively. Vines partitioned photosynthates to storage roots during prolonged dry spells— another indication of survival. The ability of some clones to reach 9 and 11 months with few vines at Umbeluzi and Nwallate offers a source of planting material for the subsequent season. This planting material is also an important source of food for farmers since home storage of roots usually does not go beyond 3 months. The rates of sprouting were also significantly different among clones. The released varieties group sprouted earlier than others; ‘Melinda’ was the earliest. Total biomass and plant architecture are key to vine survival under long dry spells in sweetpotato.
Maria I. Andrade
Theme 3: Vine survival of sweetpotato [Ipomoea batatas (L.) Lam.] cultivars s...
Theme 3: Vine survival of sweetpotato [Ipomoea batatas (L.) Lam.] cultivars s...African Potato Association (APA)
Sweetpotato is cultivated in all regions of Côte d'Ivoire for consumption and as a source of income. Only varieties with white and yellow flesh are grown. Production of nutritious orange-fleshed sweetpotato (OFSP) is hampered by the lack of genetic resources and planting material. To evaluate and release OFSP varieties, on-farm demonstration tests were conducted with women farmer groups in Bondoukou, Nassian, Korhogo, and Bondiali in north and north-east Côte d’Ivoire. Six varieties—‘Kabode’, ‘Kakamega7’ (‘Irene’), ‘Tacha2’, ‘Bela Bela’, ‘Vita’, and TIB-440060—were evaluated in comparison with locally grown varieties. The on-farm demonstration was laid out in a randomised complete block design replicated three times per location. Assessments were made on yield; disease and pests; and consumer preference on attractiveness of skin colour and flesh of the root (fresh and boiled), taste, texture, and starchiness. Results showed that introduced varieties have generally recorded higher yields than the local varieties: Yields of about 25 t/ha have been recorded on the sites. The best average yield, about 15 t/ha, was recorded for TIB-440060 and ‘Kakamega7’ varieties. Farmers’ acceptance of OFSP varieties based on the attractiveness of their colour and taste was more than 90%. At the end of the sensory tests, ‘Kakamega7’, which achieved the best compromise between all observed and measured parameters, was most appreciated and was the farmers’ first choice, followed by varieties TIB-440060 and ‘Bela Bela’.
K.E. Brice DibiParticipatory selection of orange-fleshed sweetpotato varieties in north and ...
Participatory selection of orange-fleshed sweetpotato varieties in north and ...African Potato Association (APA)
Abstract
High temperatures are among the major stresses that affect potato production in the tropics. Climate change is already affecting weather patterns in traditional potato growing areas, where unpredictable rainfall and higher temperatures contribute to increased pressure from pests and diseases and put yield and quality at risk. High temperatures can lead to increased concentrations of glycoalkaloid, which is known to cause the bitter taste in potatoes and can have a negative effect on human health. Since 2004, the International Potato Center has sought to improve the heat tolerance of its late blight-resistant population B3 by developing the new “LBHT” sub-population. We determined the narrow-sense heritability of yield components, broad-sense heritability of glycoalkaloid concentrations, and correlations between these traits in LBHT in order to ensure the quality of heat-tolerant potato clones. Thirty-two LBHT clones were crossed in sets under North Carolina Design II to obtain 64 progenies. Progeny tests were conducted in three locations in Peru: San Ramon, La Molina, and Majes, where average night:day temperatures ranged 15.1°–22.6°C and 22.9°–27.5°C, respectively, using randomised complete block designs (RCBD) with four sets and three replications of 50 genotypes per progeny. Twenty LBHT clones were grown in the same locations using RCBD with three replications. At harvest, the number and weight of marketable and non-marketable tubers were recorded, samples of tubers of each clone were taken, and glycoalkaloid concentrations were determined by spectrophotometry. Narrow-sense heritability for tuber yield, tuber number, and average tuber weight were 0.41, 0.50, and 0.83, respectively. Correlation of tuber number and average tuber weight was highly significant with tuber yield: r=0.77 and 0.74, R²=0.59 and 0.54, respectively. The heritability and correlation values indicate that additive genetic variance was higher than non-additive genetic variance, and that yield components can be used as indirect selection criterion for tuber yield. Broad-sense heritability for glycoalkaloid concentrations on fresh weight was 0.63, and correlation between glycoalkaloid concentrations and tuber yield under high temperatures was low (r=0.33 and R²=0.11). High heritability and low correlation between yield and glycoalkaloid concentrations will allow the selection of clones with high tuber yield and low glycoalkaloid content under heat and virus pressure in humid tropical San Ramon. Eight clones that showed good tuber yield and low glycoalkaloid concentrations can serve as candidate varieties, and may be valuable parents in breeding programmes aimed at improving heat tolerance with minimum risk of glycoalkaloid accumulation under stress
Manuel GasteloHeritability for yield and glycoalkaloid content in potato breeding for heat ...
Heritability for yield and glycoalkaloid content in potato breeding for heat ...African Potato Association (APA)
The Ethiopian potato research programme has released more than 30 new varieties, selected primarily for yield potential and late blight tolerance; however, the majority of farmers still choose to grow “local varieties”. Cognizant of this, the current study was aimed at identifying traits that farmers consider most important when deciding which varieties to grow. The study was conducted at two sites in North-west Ethiopia that represent two major agro-ecological zones in two distinct growing seasons, using a participatory variety selection approach. Disease-free seed tubers of nine local and three released varieties were planted. Twenty-three traits were found to influence the varieties that farmers selected, with the degree of importance of each trait differing by agro-ecological zone and gender. Of the 23 traits, 12 were considered very important and 6 determined the acceptance of a variety with their importance differing over seasons. The results showed that farmers’ selection criteria are very diverse, no variety possesses all desirable characteristics, and there is a need for selecting varieties adapted to different agro-ecologies and growing seasons. This study further suggests that taking farmers’ interests into account and the use of local varieties are important in potato breeding in Ethiopia.
Semagn Asredie Kolech;Participatory variety selection: a tool to understand farmers’ potato variety...
Participatory variety selection: a tool to understand farmers’ potato variety...African Potato Association (APA)
Abstract
The study examined preferences, perceived barriers, and factors influencing potato consumption by households in the Jos metropolis, Nigeria. The study used cross-sectional data from 180 households in 2007 and 2008 collected each year through structured questionnaire and by multistage and simple random sampling technique. The data were analysed using simple descriptive statistics, the logit model, and Kruskal-Wallis non-parametric test. The study found that potato fries (88.89%), potato porridge (81.67%), potato chips (71.11%), and potato boiled with water (68.89%), in that order, are the most familiar and frequently consumed potato food forms by households. The study revealed that 81.67% and 64.44% of households were hearing of potato flour and potato starch for the first time. Forty-four percent of the respondents reported eating raw potato for medicinal purposes. The maximum likelihood estimates of logistic regression model indicated that potato consumption pattern of households is influenced by location, health status, religion, meal time, taste, festival, and season of production (p<0.05).><0.05). The study recommended scaling up potato production and diversification of potato food forms as means to improve households’ supply of food and nutrient content. It also advocates increase nutritional education to households to correct poor food habits and barriers limiting potato consumption by households.
D.M. LenkaMonday 2: Analysis of preferences, perceived barriers, and factors influencin...
Monday 2: Analysis of preferences, perceived barriers, and factors influencin...African Potato Association (APA)
Abstract
Storage of sweetpotato roots for a prolonged period is a great challenge at the smallholder farmer level in Mozambique. Piecemeal harvesting allows a continuous supply of roots for household consumption for several months if weevil infestation is avoided. No systematic study has been done to look at the dynamic changes in yield and nutritional content among orange-fleshed sweetpotato (OFSP) cultivars harvested at different times in Mozambique. The objectives of the studies were to determine yield and changes in key macro- and micronutrients associated with early or late harvesting of OFSP cultivars in Mozambique. Four trials were established at Gurué in December 2015. The trials were classified into harvesting period, 3, 4, 5, and 6 months. Each trial had 30 OFSP cultivars laid in a randomised complete block design with three replications. Twenty-two of the cultivars are already released in Mozambique, 2 are elite clones, and 3 are common checks in 2016. Yield measurements were done in the field and samples were selected and sent to the quality laboratory in Maputo for determination of dry matter (%), β-carotene (mg/100g dry weight basis [dwb]), iron (mg/100g dwb), zinc (mg/100g dwb), and carbohydrate content, including starch, using near-infrared spectrometry. Data of the collected traits were analysed using R. The cultivars had significant differences in the measured traits within each harvesting period and among the harvesting dates. Yield and dry matter sharply rose as the harvesting period increased from the date of planting. Sweetpotato is perennial, hence partitioning of photosynthates to the storage roots is a continuous process. Dry matter, starch, iron, and β-carotene increased linearly in some cultivars as harvesting was prolonged; zinc was not affected by harvesting period. Genotype x environment interaction was small for the quality traits. Stability of micronutrients is essential for piecemeal harvesting. The study allowed accurate grouping of the cultivars tested into maturity groups as this was never done before
Abilio AlvaroTheme 2: Yield and nutrition quality stability of orange-fleshed sweetpotato ...
Theme 2: Yield and nutrition quality stability of orange-fleshed sweetpotato ...African Potato Association (APA)
Abstract
Biofortification, which is the development and dissemination of micronutrient-dense staple crops such as orange-fleshed sweetpotato (OFSP), is an effective approach to provide rural households with a low-cost source of vitamin A-rich food. Given that sweetpotato is cultivated twice a year in Western Kenya, high OFSP uptake should increase the frequency of intake of vitamin A among young children and women. The current study aimed to understand the influence of OFSP adoption and its intensity (i.e. share of OFSP in sweetpotato area) in improving women and children’s dietary diversity and intake of vitamin A-rich food. Data were analysed from the endline study of a 5-year, integrated agriculture–health project in Western Kenya. The project linked access to OFSP vines to public health services for pregnant women. In total, 1,924 mother–child pairs (children <2 years of age) were randomly selected in four intervention areas and four control areas. Two-stage instrumental variable and ordered logit regression models were employed to test the effect of adoption. Diagnostic tests for endogeneity and misspecification were conducted to confirm model validity. Two indices were identified: first, a dietary diversity index (9 food groups consumed in the previous 24 hr); second, an index of the frequency of consumption of vitamin A-rich foods during the 7 days prior to the interview. Not surprising, staple foods are the dominant food group, with less frequent consumption of nutrient-rich fruits and vegetables. The surveyed households reported consuming starchy staples (91%), dark green leafy vegetables (80%), fruits and vegetables rich in vitamin A (26%), other fruits and vegetables (58%), organ meat (2%), meat and fish (32%), egg (11%), legumes (31%), and milk products (80%). Women and children in households growing OFSP had 15% and 18% higher dietary diversity index scores, respectively, than those not growing OFSP. Similarly, the index capturing frequency of intakes of vitamin A-rich food was 10% and 20%, higher for women and children in OFSP growing households, respectively, than those who do not grow. Age of household head, mother’s education, wealth index, and the sweetpotato plots have a positive effect on the dietary diversity and frequency of vitamin A intake. Households with limited access to a health facility, larger household size, and mother engaged in casual labour have less diversified diets and consume vitamin A-rich food less frequently. Both OFSP adoption and the share of OFSP area have positive influence on dietary diversity and vitamin A intake for both women and children under 2 years in Western Kenya
Temesgen F. BocherMonday 2: Orange-fleshed sweetpotato adoption improved dietary quality: evide...
Monday 2: Orange-fleshed sweetpotato adoption improved dietary quality: evide...African Potato Association (APA)
Abstract
Biofortification is a well-known strategy for breeding to increase the nutritional value of staple crops in essential micronutrients such as vitamin A, Fe, and Zn. Biofortification differs from ordinary fortification because it focuses on making plant foods more nutritious, rather than having nutrients added to the foods when they are processed. The World Health Organisation estimated that biofortification could help cure the 2 billion people worldwide suffering from Fe deficiency-induced anaemia. Potato biofortification to increase Fe and Zn concentrations was initiated at the International Potato Center (CIP) in 2004, from a base population of Andean landraces selected for both their outstanding culinary attributes and Fe and Zn concentrations above mean levels found in extensive germplasm evaluation. After three cycles of recurrent selection, the concentrations of Fe and Zn exceeded twice those of the base population (28–40 mg/kg dry weight basis and 27–35 mg/kg dry weight basis for Fe and Zn, respectively). These are the first-ever genetic gains reported for mineral content of potato. Considering the high potato consumption (300–500 g/day) of our target populations of the African highlands, consumption of these potatoes can cover 30–75% of the Estimated Average Requirement of Fe and Zn for women of childbearing age. CIP is carrying out strategic interploid crossing with top tetraploid parental lines leading to higher yielding, disease-resistant populations of biofortified potatoes. The programme has introduced significant amounts of enhanced germplasm to Africa and built capacity for potato tuber sampling and sample preparation for mineral evaluation through on-the-job training in Ethiopia and Rwanda. It has developed an African quality evaluation network for potato using X-ray fluorescent and near-infrared spectrometry technologies. Statutory and participatory evaluation of novel potato populations have assessed user preferences for new potato types and identified elite clones for variety release. Collection of gender-disaggregated preference data is supported by CIP’s ontology-based data dictionary for technical and preference/sensory traits. CIP and partners recently demonstrated the high bioaccessibility of Fe from potato with respect to that of other staple crops. Some 63–79% of the Fe in potato is released from the food matrix during in-vitro gastro-intestinal digestion and is therefore available at the intestinal level. This compares favourably with, for example, pearl millet which is considered a success among biofortified crops, and for which the in-vitro bioaccessibility of Fe varies 10–24%, whereas it is only 5% for wheat.
Merideth BonierbaleTheme 2: Development of mineral-biofortified potato to help overcome micronut...
Theme 2: Development of mineral-biofortified potato to help overcome micronut...African Potato Association (APA)
Demese Chnayalew,
Abstract
The crop development policies and strategies of the Federal Democratic Republic of Ethiopia focus on three major categories: food, industrial, and export crops. Among the food crops, potatoes and sweetpotatoes are valuable for food and nutrition security at household level, providing highly nutritious quality protein, vitamins, and micronutrients. Recently, potato has come to be viewed as an alternative crop for climate change adaptation, too. Despite this, the crop development policies and strategies are biased towards grain. This bias, along with related policies and strategies, has partly contributed to the low levels of cultivated area and production of root and tubers in general and potato and sweetpotato in particular. Within an agricultural research and development environment dominated by grain development policies and strategies, however, research and extension institutions never quit generating, developing, multiplying, and distributing improved potato and sweetpotato technologies, including varieties and agronomic practices. This paper assesses the technology generation and adoption in different parts of the country; it analyses existing policies, strategies, and institutional arrangements. Information generated through documentation review and discussions with selected and targeted key informants provided adoption levels of improved potato and sweetpotato varieties, and helps to explain existing constraints and plausible solutions for increased productivity and production. Comparative analysis is also made with other developing countries, specifically those in the East Africa region as a whole
Food security, nutrition-sensitive agriculture, and technology adoption: the ...
Food security, nutrition-sensitive agriculture, and technology adoption: the ...African Potato Association (APA)
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Abstract
In Tigray, Ethiopia, maize is the principal cereal crop grown both under rain-fed and irrigation schemes. Potatoes have been grown for decades as a major vegetable crop and for income generation. And although both crops are grown mainly in mono-cropping, some farmers practiced intercropping without distinctive plant arrangement. Moreover, no research work has been conducted on the productivity of the system in the region. The objective of our study was to examine the potential of intercropping of maize–potato within a cereal cropping system to increase food production and income of rural households. To investigate the best production niches and highest land use efficiency for the productivity of maize–potato intercropping. The experiment was conducted during the 2012 cropping season at Hawzen Bureau of Agriculture nursery site, and consisted of three combination ratios (2:1, 1:1, 1:2) in maize–potato row arrangements and maize–potato monocropping. The experiment was laid out in a randomised complete block design with three replications. ‘Melekasa II’ and ‘Gera’ varieties were used for maize and potato, respectively. Both crops were planted simultaneously in rows 75 cm apart with 30-cm intra-row spacing. Fertilisers were applied at rates of 50 kg urea and 100 kg DAP/ha for maize and 195 kg DAP/ha and 165 kg/ha urea for potato. Data were subjected to analysis of variance. Mean comparison was performed using Duncan's new multiple range test, and land equivalent ratio (LER) index was used to evaluate intercrop efficiencies with respect to single crops. The analysis of variance showed significant differences on plant height and yield of maize in all treatments (p>0.01). The highest mean plant height of 238 cm was recorded from maize only and the lowest height of 198 cm from 1:1 cropping ratio. The highest grain yield of 4.7 t/ha was obtained from single crop followed by two rows of maize intercropped with one row of potato (4.4 t/ha). Partial LER showed a significant difference among treatments where two rows of maize/one row of potato gave 94% of the single crop. Highest tuber yield (34.4 t/ha) was obtained from potato only, whilst the lowest (14.09 t/ha) potato yield was obtained from two rows of maize/one row of potato. Results revealed that both maize and potato are compatible for intercropping under different cropping intensities. Partial LERs for potato and maize grown in the intercropping systems are less than unity. The highest partial LER of potato (0.80) and the least (0.41) were obtained from 1 row of maize to 2 of potatoes and 2 rows of maize to 1 of potato, respectively. Two rows of maize to 1 of potato gave the highest maize equivalence and the lowest potato equivalence. Partial equivalence of maize increased as equivalence of potato decreased. The current inter-cropping systems implied that farmers could benefit by growing the companion crops with different cropping intensity in the dry lands of Tigray.
Beyenesh Z. KidaneMonday 3: Maize and potato intercropping: a technology to increase productivi...
Monday 3: Maize and potato intercropping: a technology to increase productivi...African Potato Association (APA)
Abstract
Farmers who produce sweetpotato in Ethiopia save planting material on farm during the long dry months. Water stress and virus and weevil pressure during this period are the main causes of both the loss of farm-saved sweetpotato planting material and the country’s shortage of planting material. In other African countries, “Triple S” is a newly emerging root-based sweetpotato planting material conservation technique that has enabled small-scale farmers to conserve planting material for up to 3 months in dry periods. The dry months in Ethiopia last 3–5 months in the Southern Nations, Nationalities, and Peoples' Region (SNNPR) and 7–9 months in Tigray region, where direct adoption of the original Triple S technique is not feasible. Therefore, the aim of this study is to modify and test root-based sweetpotato planting material conservation methods appropriate for Ethiopia. In SNNPR, 12 farmer research groups compared Triple S techniques with shade conservation and conventional methods. In Tigray, an on-station trial was conducted to test the sprouting potential of different sizes (small, medium, and large) of roots stored in sand-filled containers after different storage periods. Results show that roots stored in sand-filled containers start sprouting 4–6 weeks after first being stored. On average, 82% of roots stored could sprout after 3, 4, and 5 months and be transplanted for vine multiplication. Forty-five days after transplanting, each root gave above-ground fresh vine yields of 883 g, 656 g, 680 g, and 615 g in Dorebafana, Kedidagamela, Humbo, and Mirab-Abaya woredas, respectively. Storing only 40 roots using Triple S can produce enough planting material to plant 400 m2 of land. In addition, the quality of vine produced through Triple S is better than that from farm-saved planting material in terms of being free of viruses and weevil. In our separate experiments to adapt Triple S for 8–9 months during the dry period in Tigray, 61%, 62%, and 52% of roots sprouted after 6 months of storage. The present study confirmed the potential of Triple S to increase the security of sweetpotato planting material in drought-prone areas in Ethiopia. Additional studies are being conducted to refine factors such as age and size of roots and storage and transplanting time.
Mihiretu CherinetTheme 3: Testing “Triple S” in a new context: sweetpotato planting material c...
Theme 3: Testing “Triple S” in a new context: sweetpotato planting material c...African Potato Association (APA)
Abstract
Sweetpotato produces substantial yields of both roots and vines for food and fodder at the same time on the same plot of land, making them attractive food–feed crops. Vine harvesting from sweetpotato gardens to be used either as fresh fodder or processed into silage, however, might compromise the root yield at harvest. A study was conducted to determine the effect of vine harvesting (de-topping) on root and vine yield of different sweetpotato varieties in Uganda. Experiments were set up on-station on Uganda Martyrs University farm and on-farm in Kamuli and Masaka districts in 2015 and 2016. The experiments were established with four sweetpotato varieties (‘NASPOT 11’, ‘NASPOT 12 O’, ‘NASPOT 13 O’, and a local variety) laid out in a randomised complete block design with four replicates. Data were collected on fresh root and vine weight, dry vine weight at 2 and 4 months after planting, incidence and severity of sweetpotato virus disease (SPVD), Alternaria blight, and weevil damage at harvesting. Data were analysed using Genstat (12th ed.). ‘NASPOT 11’ had the highest yield, followed by the local variety. There was a significant difference in the root yields of the different varieties for the de-topped crop and the non-de-topped crop. The non-de-topped local variety yielded 8.0 t/ha compared with the de-topped (3.4 t/ha), whereas the non-de-topped ‘NASPOT 13 O’ yielded 6.3 t/ha compared with the de-topped (4.6 t/ha). ‘NASPOT 11’ and ‘NASPOT 12 O’ were generally less affected by de-topping. De-topping at 85 days after planting results in root yield loss; all varieties had moderate resistance to SPVD and Alternaria blight. ‘NASPOT 11’ and ‘NASPOT 12 O’ are responding better to vine harvesting and are potential candidates for making sweetpotato silage.
Elizabeth AkirorTheme 3: Effect of vine harvesting on root and vine yield of different sweetp...
Theme 3: Effect of vine harvesting on root and vine yield of different sweetp...African Potato Association (APA)
Abstract
In Lake Zone, Tanzania, the Sweetpotato Action for Security and Health in Africa Marando Bora project trained farmers to become specialised multipliers to produce and distribute sweetpotato seed. The objectives of the case study were to analyse (1) how farmers and trained multipliers characterised and managed quality in sweetpotato planting material; (2) changes in skills and practices as multiplication became a specialised task; and (3) what other transactions were happening as planting material was exchanged. The study used mixed methods to investigate the sweetpotato seed system as a social and technical configuration and the processes and interactions within it. A formal survey of 88 trained decentralised vine multipliers (DVMs) was conducted in March 2013. Detailed observations and semi-structured interviews were also carried out with 21 farmers and a sub-group of the DVMs. The survey results showed that 70% of DVMs were multiplying vines 9 months after the project finished; 34% were using close spacing in beds; 61% were using conventional plant spacing on ridges for roots and vines; and 5% were using both multiplication beds and ridges. Further, 97% of DVMs irrigated from wells, springs, lake, river, or dam water; 34% used pumps. During the life of the project, 89% of DVMs used fertilizer, and 26% continued to use it after the project finished. The in-depth interviews showed that farmers selected planting material not only on the basis of plant health, but also used cues to plant vigour. The use of own-saved seed involved a complex performance of managing seed and root production across different agro-ecologies according to inter- and intra-season characteristics. As the vine multiplication cycle became a specialised activity, vines were treated differently, depending on whether they were to be used for high root production or high vine production. The resilience and viability of the existing seed systems depended not only on individual knowledge and skills, but also management practices across agro-ecologies and negotiating social settlements at community level. As specialisation of seed production developed, the multiplication and root production cycles were separated and tasks became segregated. New knowledge and skills were formed in different ways; the trained multipliers adapted the new techniques into the existing system of shifting vine conservation and root production between different ecologies. Interventions aimed at building the capacity of specialised vine multipliers and scaling-up seed interventions should consider the implications of skills-building and segregation of tasks in the broader context of society choice of technologies and agrarian change.
Margaret A. McEwanTheme 3: Specialised sweetpotato vine multiplication in Lake Zone, Tanzania: ...
Theme 3: Specialised sweetpotato vine multiplication in Lake Zone, Tanzania: ...African Potato Association (APA)
Abstract
Limited accessibility to high-quality potato seed is a perennial problem for many farmers, and can be attributed partly to inefficiencies at various stages of the seed production system. In soilless culture like aeroponics, nutrient optimisation is the most critical factor to produce high-quality, high-yielding clean potato seed. Each crop has an optimum nutritional requirement; even each potato cultivar may require a specific nutrient solution in an aeroponics unit. A nutrient optimisation experiment was conducted at the Holetta Agricultural Research Center to study the effect of different nutrient composition levels on the physical quality and yield of potato mini-tubers (here, variety ‘Belete’). There were four treatments, each with different compositions of greenhouse-grade macro-nutrients, measured in grams for the preparation of 500-L volume of nutrient solution: A = 118 gm CaNO3, 252 gm KNO3, 68 gm KH2PO4, and 100 gm MgSO4; B = 59 gm CaNO3,126 gm KNO3, 68 gm KH2PO4, and 100 gm MgSO4; C = 118 gm CaNO3, 252 gm KNO3, 68 gm KH2PO4, and 100 gm MgSO4 until flowering and reduced by half after flowering; and D = 118 gm CaNO3, 252 gm KNO3, 136 gm KH2PO4, and 100 gm MgSO4. The same level of micro-nutrients was used for all treatments. Acclimatized plantlets were planted in alternative or sequential manner from one another in a completely randomised design with three replicates. The results showed that each treatment varied in nutrient consumption rate throughout the life span of the crop. Treatment A consumed the highest amount of nutrient (3.29 kg, 28%), treatments B and D consumed the same amount (3.1 kg, 27%), and treatment C consumed the smallest amount (2.0 kg, 17%). Root length was significantly affected by nutrient solution. Nutrient solution C produced the longest root (300.8 cm), whereas nutrient solutions A, B, and D produced root lengths of 135.5, 198.3, and 174.4 cm, respectively. Plant height was not significantly affected by nutrient treatments. Small tubers (<8>12 gm) were significantly affected by nutrient treatments both in number and weight. The maximum tuber number was obtained from treatment B, followed by C and D. On the basis of these results, different nutrient solution concentrations significantly affected root length and tuber size both in number and weight. Therefore, the experiment indicated that treatment B represents the optimum nutrient concentration rate to use in an aeroponics mini-tuber production system under Holetta conditions.
Lemma Tessema GebrehannaMonday 3: Determination of nutrient solutions for potato (Solanum tuberosum L...
Monday 3: Determination of nutrient solutions for potato (Solanum tuberosum L...African Potato Association (APA)
Abstract
Pathogen-tested sweetpotato planting material is shown to provide a significant boost in yield and quality in the sweetpotato seed systems and value chains. In the absence of pathogen-tested planting material, negative selection has been shown to be effective in some cultivars and locations as well. Protective net tunnels allow decentralised vine multipliers to maintain and multiply limited quantities of clean planting material. Commercial demand for sweetpotato planting material is likely to be sustained if seed producers are able to provide evidence of the superiority of their product to their customers. The objective of this study was to evaluate the effects of net tunnel source and of pathogen-tested planting material on yield and health status (sweetpotato virus disease [SPVD] and weevil incidence) of crop. Studies were conducted in 2015, at locations in Ghana that varied with regard to SPVD and weevil pressure. Four varieties were used with pathogen-tested planting materials—‘Apomuden’, ‘Dadanyuie’, ‘Bohye’, and ‘Ligri’—and multiplied in net tunnels. ‘Apparently’ healthy (field-derived, negatively selected) material of the same varieties were also multiplied in adjacent field plots at one location in northern Ghana. For ‘Apomuden’, the apparently healthy planting material was multiplied in both net tunnel and open field at the same location. The trials were conducted at three sites in northern Ghana: Nyankpala, Navrongo, and Wa. At each site, 8 treatment combinations (4 varieties and 2 sources of planting material) were arranged in a trial design with three replicates. The 4 x 5.1 m plots were planted to 17 vine cuttings per row, spacing 0.30 m within rows and 1 m between rows, and no additional irrigation. Weeding, reshaping, and vine lifting were done at all locations. NPK (15:15:15) was applied at Navrongo and Wa, 4 weeks after planting, as recommended, due to natural poor soil fertility. Data were analysed using Genstat (12th edition). There were highly significant differences among varieties and trial sites for plant establishment, foliage yield, root yield, weevil damage, and SPVD rating; but source of planting material was not found to be significant. For SPVD, net tunnel source is better than open field (p<0.01).><0.04). The results indicate that apparently healthy planting material was as effective as pathogen-tested planting material. Net tunnels may have a distinct advantage for maintaining and multiplying planting material to produce healthy sweetpotato crops.
Putri E. AbidinMonday 3: Comparative studies on sources of sweetpotato planting material for...
Monday 3: Comparative studies on sources of sweetpotato planting material for...African Potato Association (APA)
Abstract
Production potential of sweetpotato is not realised in most regions experiencing dry spells after the growing season in sub-Saharan Africa due to lack of planting material at the beginning of the rainy season. Identifying cultivars with ability to survive a 4- to 7-month dry spell is worthwhile in improving the sweetpotato seed system in these regions. The objective of the study was to estimate survival of vines under drought stress in a collection of sweetpotato clones. Three treatments (different harvesting times set as 5, 9, and 11 months after planting) were established at Umbeluzi, Nwallate, and Gurué in February 2015. In each treatment, 37 sweetpotato clones (18 released varieties, 8 landraces, 2 check clones, and 9 foreign introductions) were evaluated in a randomised complete block design with two replications. Data collected on storage root and vine yield, virus infection, vine length, and number of sprouts were subjected to analysis of variance using SAS 1996. Clone performance varied significantly within treatments. There was a significant drop in vine yield as the harvesting period increased from 5 months at all sites. Introduced variety ‘Resisto’ had long stems but no vines remaining after 9 months at all sites. Length and thickness of vine in a clone could be traits responsible for drought tolerance in sweetpotato. Spatial soil differences affected survival of vines. Most clones could not survive after 7 months at Gurué where the soils are lighter in texture and have low capacity to retain water. At Gurué, the inability to survive for long periods was exacerbated by virus infection. Gurué is an important site for virus screening in the breeding programme. A 6–8% significant increase of storage root yield between the 5 and 9 months’ harvest was recorded at Umbeluzi and Nwallate, respectively. Vines partitioned photosynthates to storage roots during prolonged dry spells— another indication of survival. The ability of some clones to reach 9 and 11 months with few vines at Umbeluzi and Nwallate offers a source of planting material for the subsequent season. This planting material is also an important source of food for farmers since home storage of roots usually does not go beyond 3 months. The rates of sprouting were also significantly different among clones. The released varieties group sprouted earlier than others; ‘Melinda’ was the earliest. Total biomass and plant architecture are key to vine survival under long dry spells in sweetpotato.
Maria I. Andrade
Theme 3: Vine survival of sweetpotato [Ipomoea batatas (L.) Lam.] cultivars s...
Theme 3: Vine survival of sweetpotato [Ipomoea batatas (L.) Lam.] cultivars s...African Potato Association (APA)
Sweetpotato is cultivated in all regions of Côte d'Ivoire for consumption and as a source of income. Only varieties with white and yellow flesh are grown. Production of nutritious orange-fleshed sweetpotato (OFSP) is hampered by the lack of genetic resources and planting material. To evaluate and release OFSP varieties, on-farm demonstration tests were conducted with women farmer groups in Bondoukou, Nassian, Korhogo, and Bondiali in north and north-east Côte d’Ivoire. Six varieties—‘Kabode’, ‘Kakamega7’ (‘Irene’), ‘Tacha2’, ‘Bela Bela’, ‘Vita’, and TIB-440060—were evaluated in comparison with locally grown varieties. The on-farm demonstration was laid out in a randomised complete block design replicated three times per location. Assessments were made on yield; disease and pests; and consumer preference on attractiveness of skin colour and flesh of the root (fresh and boiled), taste, texture, and starchiness. Results showed that introduced varieties have generally recorded higher yields than the local varieties: Yields of about 25 t/ha have been recorded on the sites. The best average yield, about 15 t/ha, was recorded for TIB-440060 and ‘Kakamega7’ varieties. Farmers’ acceptance of OFSP varieties based on the attractiveness of their colour and taste was more than 90%. At the end of the sensory tests, ‘Kakamega7’, which achieved the best compromise between all observed and measured parameters, was most appreciated and was the farmers’ first choice, followed by varieties TIB-440060 and ‘Bela Bela’.
K.E. Brice DibiParticipatory selection of orange-fleshed sweetpotato varieties in north and ...
Participatory selection of orange-fleshed sweetpotato varieties in north and ...African Potato Association (APA)
Abstract
High temperatures are among the major stresses that affect potato production in the tropics. Climate change is already affecting weather patterns in traditional potato growing areas, where unpredictable rainfall and higher temperatures contribute to increased pressure from pests and diseases and put yield and quality at risk. High temperatures can lead to increased concentrations of glycoalkaloid, which is known to cause the bitter taste in potatoes and can have a negative effect on human health. Since 2004, the International Potato Center has sought to improve the heat tolerance of its late blight-resistant population B3 by developing the new “LBHT” sub-population. We determined the narrow-sense heritability of yield components, broad-sense heritability of glycoalkaloid concentrations, and correlations between these traits in LBHT in order to ensure the quality of heat-tolerant potato clones. Thirty-two LBHT clones were crossed in sets under North Carolina Design II to obtain 64 progenies. Progeny tests were conducted in three locations in Peru: San Ramon, La Molina, and Majes, where average night:day temperatures ranged 15.1°–22.6°C and 22.9°–27.5°C, respectively, using randomised complete block designs (RCBD) with four sets and three replications of 50 genotypes per progeny. Twenty LBHT clones were grown in the same locations using RCBD with three replications. At harvest, the number and weight of marketable and non-marketable tubers were recorded, samples of tubers of each clone were taken, and glycoalkaloid concentrations were determined by spectrophotometry. Narrow-sense heritability for tuber yield, tuber number, and average tuber weight were 0.41, 0.50, and 0.83, respectively. Correlation of tuber number and average tuber weight was highly significant with tuber yield: r=0.77 and 0.74, R²=0.59 and 0.54, respectively. The heritability and correlation values indicate that additive genetic variance was higher than non-additive genetic variance, and that yield components can be used as indirect selection criterion for tuber yield. Broad-sense heritability for glycoalkaloid concentrations on fresh weight was 0.63, and correlation between glycoalkaloid concentrations and tuber yield under high temperatures was low (r=0.33 and R²=0.11). High heritability and low correlation between yield and glycoalkaloid concentrations will allow the selection of clones with high tuber yield and low glycoalkaloid content under heat and virus pressure in humid tropical San Ramon. Eight clones that showed good tuber yield and low glycoalkaloid concentrations can serve as candidate varieties, and may be valuable parents in breeding programmes aimed at improving heat tolerance with minimum risk of glycoalkaloid accumulation under stress
Manuel GasteloHeritability for yield and glycoalkaloid content in potato breeding for heat ...
Heritability for yield and glycoalkaloid content in potato breeding for heat ...African Potato Association (APA)
The Ethiopian potato research programme has released more than 30 new varieties, selected primarily for yield potential and late blight tolerance; however, the majority of farmers still choose to grow “local varieties”. Cognizant of this, the current study was aimed at identifying traits that farmers consider most important when deciding which varieties to grow. The study was conducted at two sites in North-west Ethiopia that represent two major agro-ecological zones in two distinct growing seasons, using a participatory variety selection approach. Disease-free seed tubers of nine local and three released varieties were planted. Twenty-three traits were found to influence the varieties that farmers selected, with the degree of importance of each trait differing by agro-ecological zone and gender. Of the 23 traits, 12 were considered very important and 6 determined the acceptance of a variety with their importance differing over seasons. The results showed that farmers’ selection criteria are very diverse, no variety possesses all desirable characteristics, and there is a need for selecting varieties adapted to different agro-ecologies and growing seasons. This study further suggests that taking farmers’ interests into account and the use of local varieties are important in potato breeding in Ethiopia.
Semagn Asredie Kolech;Participatory variety selection: a tool to understand farmers’ potato variety...
Participatory variety selection: a tool to understand farmers’ potato variety...African Potato Association (APA)
Abstract
The study examined preferences, perceived barriers, and factors influencing potato consumption by households in the Jos metropolis, Nigeria. The study used cross-sectional data from 180 households in 2007 and 2008 collected each year through structured questionnaire and by multistage and simple random sampling technique. The data were analysed using simple descriptive statistics, the logit model, and Kruskal-Wallis non-parametric test. The study found that potato fries (88.89%), potato porridge (81.67%), potato chips (71.11%), and potato boiled with water (68.89%), in that order, are the most familiar and frequently consumed potato food forms by households. The study revealed that 81.67% and 64.44% of households were hearing of potato flour and potato starch for the first time. Forty-four percent of the respondents reported eating raw potato for medicinal purposes. The maximum likelihood estimates of logistic regression model indicated that potato consumption pattern of households is influenced by location, health status, religion, meal time, taste, festival, and season of production (p<0.05).><0.05). The study recommended scaling up potato production and diversification of potato food forms as means to improve households’ supply of food and nutrient content. It also advocates increase nutritional education to households to correct poor food habits and barriers limiting potato consumption by households.
D.M. LenkaMonday 2: Analysis of preferences, perceived barriers, and factors influencin...
Monday 2: Analysis of preferences, perceived barriers, and factors influencin...African Potato Association (APA)
Abstract
Storage of sweetpotato roots for a prolonged period is a great challenge at the smallholder farmer level in Mozambique. Piecemeal harvesting allows a continuous supply of roots for household consumption for several months if weevil infestation is avoided. No systematic study has been done to look at the dynamic changes in yield and nutritional content among orange-fleshed sweetpotato (OFSP) cultivars harvested at different times in Mozambique. The objectives of the studies were to determine yield and changes in key macro- and micronutrients associated with early or late harvesting of OFSP cultivars in Mozambique. Four trials were established at Gurué in December 2015. The trials were classified into harvesting period, 3, 4, 5, and 6 months. Each trial had 30 OFSP cultivars laid in a randomised complete block design with three replications. Twenty-two of the cultivars are already released in Mozambique, 2 are elite clones, and 3 are common checks in 2016. Yield measurements were done in the field and samples were selected and sent to the quality laboratory in Maputo for determination of dry matter (%), β-carotene (mg/100g dry weight basis [dwb]), iron (mg/100g dwb), zinc (mg/100g dwb), and carbohydrate content, including starch, using near-infrared spectrometry. Data of the collected traits were analysed using R. The cultivars had significant differences in the measured traits within each harvesting period and among the harvesting dates. Yield and dry matter sharply rose as the harvesting period increased from the date of planting. Sweetpotato is perennial, hence partitioning of photosynthates to the storage roots is a continuous process. Dry matter, starch, iron, and β-carotene increased linearly in some cultivars as harvesting was prolonged; zinc was not affected by harvesting period. Genotype x environment interaction was small for the quality traits. Stability of micronutrients is essential for piecemeal harvesting. The study allowed accurate grouping of the cultivars tested into maturity groups as this was never done before
Abilio AlvaroTheme 2: Yield and nutrition quality stability of orange-fleshed sweetpotato ...
Theme 2: Yield and nutrition quality stability of orange-fleshed sweetpotato ...African Potato Association (APA)
Abstract
Biofortification, which is the development and dissemination of micronutrient-dense staple crops such as orange-fleshed sweetpotato (OFSP), is an effective approach to provide rural households with a low-cost source of vitamin A-rich food. Given that sweetpotato is cultivated twice a year in Western Kenya, high OFSP uptake should increase the frequency of intake of vitamin A among young children and women. The current study aimed to understand the influence of OFSP adoption and its intensity (i.e. share of OFSP in sweetpotato area) in improving women and children’s dietary diversity and intake of vitamin A-rich food. Data were analysed from the endline study of a 5-year, integrated agriculture–health project in Western Kenya. The project linked access to OFSP vines to public health services for pregnant women. In total, 1,924 mother–child pairs (children <2 years of age) were randomly selected in four intervention areas and four control areas. Two-stage instrumental variable and ordered logit regression models were employed to test the effect of adoption. Diagnostic tests for endogeneity and misspecification were conducted to confirm model validity. Two indices were identified: first, a dietary diversity index (9 food groups consumed in the previous 24 hr); second, an index of the frequency of consumption of vitamin A-rich foods during the 7 days prior to the interview. Not surprising, staple foods are the dominant food group, with less frequent consumption of nutrient-rich fruits and vegetables. The surveyed households reported consuming starchy staples (91%), dark green leafy vegetables (80%), fruits and vegetables rich in vitamin A (26%), other fruits and vegetables (58%), organ meat (2%), meat and fish (32%), egg (11%), legumes (31%), and milk products (80%). Women and children in households growing OFSP had 15% and 18% higher dietary diversity index scores, respectively, than those not growing OFSP. Similarly, the index capturing frequency of intakes of vitamin A-rich food was 10% and 20%, higher for women and children in OFSP growing households, respectively, than those who do not grow. Age of household head, mother’s education, wealth index, and the sweetpotato plots have a positive effect on the dietary diversity and frequency of vitamin A intake. Households with limited access to a health facility, larger household size, and mother engaged in casual labour have less diversified diets and consume vitamin A-rich food less frequently. Both OFSP adoption and the share of OFSP area have positive influence on dietary diversity and vitamin A intake for both women and children under 2 years in Western Kenya
Temesgen F. BocherMonday 2: Orange-fleshed sweetpotato adoption improved dietary quality: evide...
Monday 2: Orange-fleshed sweetpotato adoption improved dietary quality: evide...African Potato Association (APA)
Abstract
Biofortification is a well-known strategy for breeding to increase the nutritional value of staple crops in essential micronutrients such as vitamin A, Fe, and Zn. Biofortification differs from ordinary fortification because it focuses on making plant foods more nutritious, rather than having nutrients added to the foods when they are processed. The World Health Organisation estimated that biofortification could help cure the 2 billion people worldwide suffering from Fe deficiency-induced anaemia. Potato biofortification to increase Fe and Zn concentrations was initiated at the International Potato Center (CIP) in 2004, from a base population of Andean landraces selected for both their outstanding culinary attributes and Fe and Zn concentrations above mean levels found in extensive germplasm evaluation. After three cycles of recurrent selection, the concentrations of Fe and Zn exceeded twice those of the base population (28–40 mg/kg dry weight basis and 27–35 mg/kg dry weight basis for Fe and Zn, respectively). These are the first-ever genetic gains reported for mineral content of potato. Considering the high potato consumption (300–500 g/day) of our target populations of the African highlands, consumption of these potatoes can cover 30–75% of the Estimated Average Requirement of Fe and Zn for women of childbearing age. CIP is carrying out strategic interploid crossing with top tetraploid parental lines leading to higher yielding, disease-resistant populations of biofortified potatoes. The programme has introduced significant amounts of enhanced germplasm to Africa and built capacity for potato tuber sampling and sample preparation for mineral evaluation through on-the-job training in Ethiopia and Rwanda. It has developed an African quality evaluation network for potato using X-ray fluorescent and near-infrared spectrometry technologies. Statutory and participatory evaluation of novel potato populations have assessed user preferences for new potato types and identified elite clones for variety release. Collection of gender-disaggregated preference data is supported by CIP’s ontology-based data dictionary for technical and preference/sensory traits. CIP and partners recently demonstrated the high bioaccessibility of Fe from potato with respect to that of other staple crops. Some 63–79% of the Fe in potato is released from the food matrix during in-vitro gastro-intestinal digestion and is therefore available at the intestinal level. This compares favourably with, for example, pearl millet which is considered a success among biofortified crops, and for which the in-vitro bioaccessibility of Fe varies 10–24%, whereas it is only 5% for wheat.
Merideth BonierbaleTheme 2: Development of mineral-biofortified potato to help overcome micronut...
Theme 2: Development of mineral-biofortified potato to help overcome micronut...African Potato Association (APA)
Demese Chnayalew,
Abstract
The crop development policies and strategies of the Federal Democratic Republic of Ethiopia focus on three major categories: food, industrial, and export crops. Among the food crops, potatoes and sweetpotatoes are valuable for food and nutrition security at household level, providing highly nutritious quality protein, vitamins, and micronutrients. Recently, potato has come to be viewed as an alternative crop for climate change adaptation, too. Despite this, the crop development policies and strategies are biased towards grain. This bias, along with related policies and strategies, has partly contributed to the low levels of cultivated area and production of root and tubers in general and potato and sweetpotato in particular. Within an agricultural research and development environment dominated by grain development policies and strategies, however, research and extension institutions never quit generating, developing, multiplying, and distributing improved potato and sweetpotato technologies, including varieties and agronomic practices. This paper assesses the technology generation and adoption in different parts of the country; it analyses existing policies, strategies, and institutional arrangements. Information generated through documentation review and discussions with selected and targeted key informants provided adoption levels of improved potato and sweetpotato varieties, and helps to explain existing constraints and plausible solutions for increased productivity and production. Comparative analysis is also made with other developing countries, specifically those in the East Africa region as a whole
Food security, nutrition-sensitive agriculture, and technology adoption: the ...
Food security, nutrition-sensitive agriculture, and technology adoption: the ...African Potato Association (APA)
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- 1. Carbohydrate composition, viscosity, solubility and sensory acceptability of sweetpotato‐ and maize‐based complementary foods Francis Kweku Amagloh*, Anthony N. Mutukumira, Louise Brough, Janet L. Weber, Allan Hardacre and Jane Coad *fkamagloh@uds.edu.gh Citation: Amagloh, F. K., Mutukumira, A. N., Brough, L., Weber, J. L., Hardacre, A. and Coad, J. 2013. Carbohydrate composition, viscosity, solubility, and sensory acceptance of sweetpotato‐ and maize‐based complementary foods. Food and Nutrition Research, 57, 1871
- 2. Outline • Background • Methods • Results & Discussion • Limitation • Conclusion • Recommendation Awesome scenery, Queenstown, NZ
- 3. Background, the gloomy picture Bhutta Z A et al. Evidence‐based interventions for improvement of maternal and child nutrition: what can be done and at what cost? The Lancet, 2013, Epub ahead of print
- 4. Background Contd • “Deficiencies of vitamin A and zinc result in deaths; deficiencies of iodine and iron, together with stunting, can contribute to children not reaching their developmental potential.” Black R E et al. Maternal and child undernutrition and overweight in low‐income and middle‐ income countries. The Lancet, 2013: Epub ahead of print • “However, evidence of the nutritional effect of agricultural programmes is inconclusive—except for vitamin A from biofortification of orange sweet potatoes—largely because of poor quality evaluations.” Ruel M T et al. Nutrition‐sensitive interventions and programmes: how can they help to accelerate progress in improving maternal and child nutrition? The Lancet, 2013, Epub ahead of print
- 5. Background Contd. • To address VAD, the ComFa complementary food blends‐ cream‐fleshed sweetpotato, soyabean, oil, fish powder/skimmed milk were developed as alternative to maize‐ soyabean‐groundnut blend (Weanimix)* • Both the sweetpotato‐ and maize‐based met the energy (1670 kJ/100 g) and fat (10‐25 g/100 g) stipulated levels in the Codex Standard * Amagloh F K et al. Sweet potato‐based complementary food for infants in low‐ income countries. Food Nutr. Bull., 2012, 33: 3‐10
- 6. Background Contd. • Extrusion‐cooked ComFa and roller‐dried ComFa containing skimmed milk (industrial‐ level product) contained 83% of the recommended protein content of 15 g/100 g in complementary food in the Codex standard • But oven‐toasted ComFa containing fish powder and Weanimix met 100% the protein requirement
- 7. Background Contd. • Nutritional advantages of ComFa over Weanimix – Relatively low in phytate (a quarter of level in Weanimix)♣ – Phytate: mineral molar ratios for Ca, Fe and Zn predicted that the ComFa formulations may not adversely affect absorption of these minerals♣ – High in retinol activity equivalent (28 vs. 2 RAE/100 kcal)∗ ♣ Amagloh F K et al. Sweetpotato‐based complementary food would be less inhibitory on mineral absorption than a maize‐based infant food assessed by compositional analysis. Int. J. Food Sci. Nutr., 2012, 63: 957‐963 ∗ Amagloh F K et al. A household‐level sweet potato‐based infant food to complement vitamin A supplementation initiatives. Matern. Child Nutr., 2012, 8: 512‐521
- 8. Background Contd. • Cereal‐based complementary foods from non‐ malted ingredients form a relatively high viscous porridge • Therefore, excessive dilution, usually with water, is required to reduce the viscosity to be appropriate for infant feeding • The dilution invariably leads to “energy and nutrient thinning”, that is, the reduction of energy and nutrient densities
- 9. Objectives • To compare the sweetpotato‐based complementary foods (extrusion‐cooked ComFa, roller‐dried ComFa and oven‐toasted ComFa) and enriched Weanimix (maize‐based formulation) regarding their: • Carbohydrate composition; • Viscosity; • Water solubility index; and • Sensory acceptability evaluated by sub‐Sahara African women as model caregivers.
- 12. Physicochemical and sensory evaluation • Simple sugars: spectrophotometry (Megazyme assay kit) • Total dietary fibre by enzymatic‐gravimetric method (Megazyme assay kit) • Total carbohydrate and starch levels: by calculation • Apparent viscosity: A Rapid Visco™ Analyser • Water solubility Index: Gravimetrically. • Sensory evaluation: consumer sensory evaluation was used to evaluate the product acceptance of the roller‐ dried ComFa, oven‐toasted ComFa and enriched Weanimix.
- 13. Results & Discussion‐Carbohydrate composition* Complementary food Maltose Sucrose Free glucose Free fructose Starch§ Total dietary fibre Total available carbohydrate Sweetpotato-based Extrusion-cooked ComFa 27.50 (2.45)a 10.20 (0.31)a 1.24 (0.04)b 3.07 (0.37)a 11.32 (1.87)b 10.25 (2.29)a 56.07 (1.97)a Roller-dried ComFa 30.85 (3.84)a 10.53 (1.06)a 1.34 (0.03)a 2.94 (1.04)a 10.53 (3.70)b 10.57 (1.21)a 58.92 (0.83)a Oven-toasted ComFa 25.43 (1.17)a 10.08 (0.43)a 1.40 (0.05)a 2.61 (0.46)a 13.75 (0.72)b 8.16 (0.77)a,b 53.28 (0.94)a,b Maize-based Enriched Weanimix 1.06 (0.18)b 2.01 (0.12)b 0.07 (0.02)c 0.39 (0.13)b 46.72 (0.64)a 6.08 (0.44)b 50.25 (0.75)b P-value <0.0001 <0.0001 <0.0001 0.002 <0.0001 0.01 <0.0001 §Starch=total available carbohydrate minus sum of maltose, sucrose, free glucose and free fructose; the starch content for extrusion‐cooked ComFa and roller‐dried ComFa was corrected for approximately 3 g/100 g of lactose from skim milk powder used as an ingredient *Value is mean (standard deviation) of triplicate; values with the same superscript letter in a column are not significantly different (P >0.05)
- 14. Results & Discussion‐ Apparent Viscosity 0 200 400 600 800 1000 1200 1400 1600 1800 Extrusion‐cooked ComFa Roller‐dried ComFa Oven‐toasted ComFa Enriched Weanimix Viscosity (cP) Complementary food Peak viscosity "Consume viscosity" Final viscosity b b b c c bc b,c a a a Bar with different letter per each variable for the complementary foods was significantly different (P <0.0001)
- 16. Results & Discussion‐ Product liking 1 2 3 4 5 6 7 8 9 Overall Acceptability Colour Smell Texture Taste Given as baby food Roller-dried ComFa Oven-toasted ComFa Enriched Weanimix Sensory attribute with P<0.05 indicates that significant difference among the complementary A 9‐point hedonic scale was used (1=least acceptable/dislike extremely; 5=Neutral; 9=highly acceptable/like extremely) for all attributes except for willingness to give product to babies (1=Not likely; 5=Neutral; 9=Very likely). P= 0.03 P= 0.06 P= 0.01 P= 0.12 P= 0.02 P= 0.03
- 17. Limitations • Cream‐fleshed sweetpotato is lower in β‐ carotene compared to the orange‐fleshed varieties • The flour preparation significantly increases the processing time of the ComFa products as sweetpotato has low dry matter • Ascorbic acid totally degraded during processing of the sweetpotato flour
- 18. Conclusion • The sweetpotato‐based formulations had a higher sugar to starch ratio than the maize‐based complementary food – lower apparent viscosity – higher WSI – less “energy and nutrient thinning” • The scores of the consumer preference given by the infant caregivers indicated highest liking for roller‐dried ComFa, followed by the oven‐toasted ComFa, and lastly, the enriched Weanimix
- 19. Concluding remarks • These findings, combined with the relatively low phytate and high vitamin A levels, and the low phytate: mineral ratio suggest that the use of sweetpotato in complementary food should be encouraged as it has potential to have significant nutritional benefit in low‐income countries • BUT there is a need for efficacy trial
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