Wheat conventional breeding method by heterosis

1. Cairo University
Faculty of Agriculture
Agronomy Dept.
Hybrid wheat: quantitative genetic parameters
and heterosis for quality and rheological traits
as well as baking volume
Theoretical and Applied Genetics (2022)
2022-2023 1
Presented by: Mohamed Hesham Elhefnawy
Under Supervision of :
Prof.Dr. Ahmed Medhat Elnaggar
Prof.Dr. Mohamed Reda Shabana
Prof.Dr. Ahmed Monged Soliman

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Introduction
Bread wheat varieties, scientifically known as
Triticum aestivum spp. aestivum, are cultivated to
meet several requirements throughout the supply
chain (Thorwarth et al., 2018).
Apart from high grain yield and disease resistance,
bread making quality is a crucial factor to consider
(Godin, 2007).
While grain yield can be measured using combine
harvesters, assessing bread making quality involves
various properties that require time-consuming test
methods (Thanhaeuser et al., 2014).
Therefore, protein content is often used as a quick
and easy measurement to predict wheat baking
quality, and it also forms the basis for the farmer
payment system in many countries (Thorwarth et al.,
2018; Boeven and Longin, 2019).

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• Hybrid wheat breeding has gained significant interest in the public and private sector (Boeven
and Longin, 2019).
• Well-established in many outcrossing species, hybrid breeding is still under development in
wheat (Gupta et al., 2019).
• Mid-parent heterosis of approximately 10% has been reported for hybrid bread and durum
wheat in terms of grain yield (Gowda et al., 2010; Thorwarth et al., 2018).
• Negative heterosis values have been observed for protein content
(Oury and Godin, 2007; Thorwarth et al., 2018, 2019; Boeven and Longin, 2019).
• Recent studies indicate the potential of hybrid bread and durum wheat to combine good
sedimentation values, acceptable protein content, and high grain yield (Thorwarth et al., 2018;
Akel et al., 2019; Boeven and Longin, 2019).
However, there is a lack of research investigating other bread making quality traits across a
large number of bread wheat hybrids and their parental lines.

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Objectives
 Our objectives were to:
(1) evaluate variance components, trait correlations and heritabilities for the
examined quality traits
(2) estimate the extend of mid- and better-parent heterosis
(3) assess the association between mid-parent value, line per se performance and
GCA effects with hybrid performance and
(4) evaluate the potential of hybrids to combine good bread making quality with
high grain yield.

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Materials & Methods:
Plant Material: The initial study included 236 elite winter bread wheat lines and their 1744
single-cross hybrid progenies. These lines were selected based on their representation of
Central European diversity. The lines were categorized into two groups: 40 males and 196
females, considering traits like pollination ability, flowering time, and plant height.
Check Varieties: In addition to the elite lines and their hybrids, 11 check varieties were
included in the study. These check varieties were named Colonia, Elixer, Hystar, Hybred,
JBAsano, Julius, KWSLoft, LGAlpha, RGTReform, Rumor, and Tobak.
Experimental Design: The hybrids were crossed in an incomplete factorial mating design.
The initial experimental setup was described in a previous study by Zhao et al. (2021). The
subsequent selection of plant material for the presented data was based on various criteria
such as agronomic traits, protein content, sedimentation value, and diversity in glutenin
bands.

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9. Single/Simple Cross

10. Hybridization:
1- plants planted as single plants as possible
2-Parents should be planted in three sucessive sowing days (15)
3-Suitable Spike must be taken

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Phenotypic Data Analysis:
• As suggested by Bernal-Vasquez et al. (2016) an outlier
detection was performed before analyzing the phenotypic
data following the method 4 ‘‘Bonferroni-Holm with re-
scaled median absolute deviation standardized residuals.”
The best linear unbiased estimators (BLUEs) were then
cal- culated based on the following mixed model (1):

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Phenotypic Data Analysis:

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Results:
No significant differences (p < 0.05) were found in the mean comparisons of males, females and hybrids,
except for higher grain yield and lower protein content in the hybrids.
Mid-parent and better-parent heterosis values were close to zero and slightly negative, respectively, for
baking volume and extensograph traits.
However, the majority of heterosis values resulted in the finding that hybrids had higher grain yield
(Average better-parent heterosis was positive only for grain yield
Trait values showed a wide range within male lines, female lines, and hybrids, except for protein content,
which was slightly higher in parental lines.
The low variance due to specific combining ability effects for most quality traits

14. The large variation in parental lines and hybrids within the individual traits, however,
allows for selection of “outliers” from that negative correlation having high yield and good
quality.

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Results:
Boxplots for different traits grouped by checks, males, females and hybrids.
Means between groups with a common letter for a given trait do not differ
significantly from each other based on Tukey’s test

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Results:
Baking volume plotted against grain yield of lines (filled symbols) and hybrids
(empty symbols) belonging to the 20% best (circles), 20% worst (triangles)
genotypes regarding sedimentation value and check varieties (red crosses)

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Conclusion
• Heterosis effects for dough quality and baking volume were close to zero. However,
hybrids have a higher grain yield at a given level of bread making quality compared to
their parental lines.
• The almost additive gene action for quality traits requires quality selection in both
heterotic groups.
• The importance of these findings on the effectiveness of hybrid versus line breeding in
wheat depends on advancements in hybrid seed production technologies and the
acceleration of hybrid programs using genomic selection and other predictive tools.

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