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Sugarcane Breeding lnstltuto
(Indian Council of Agricultural Resemh) -I
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2. ugarcane (Saccharurn spp.) is an important crop globally not only for
sugar production, but also increasingly as a bioenergy crop due to its
phenomenal dry matter production capacity. Drought is one of the most
important environmental stress limiting sugarcane production worldwide. Due
to the erratic nature of rainfall, sugarcane growers rely heavily on irrigation to
meet production goals. However, water for irrigation is a limited and continuous
resource and its effective management is critical, not only in reducing wasteful
usage, but also in reducing production costs and sustaining productivity. In view
of the sugar requirement of 27 million tonnes by the year 2020 and scope for
further increase in area under sugarcane cultivation being limited the evolution
of drought resistant varieties has become a major research priority. Hence, each
year advanced breeders materials are being evaluated in field condition with the
objective of identifyingresistant genotypes to drought.
Critical phenological phase for water demand
In sugarcane, four distinct growth stages have been characterized,
namely: germination, tillering, grand growth and maturity. The tillering phase is
known as the formative phase and has been identified as the critical water
demand period, mainly because during this phase maximum number of shoots
are formed. In most of the sugarcane growing areas, the crop experiences
moisture stress during the formative phase, affecting germination and tillering.
As a result stalk population and stalk growth are reduced, resulting in 30-50%
yield loss. Varieties response to water deficit stress during this growth stage
could therefore be useful in identlfyrng drought tolerant genotypes.
Screening methodology fBt drought tolcmce: in field
Field experiments were conducted in split plot design with control and
moisture stress treatment as main plot and genotypes as sub plot (in replicated
.id) to evaluate the elite breeders materials (lVT/AVT genotypes) for drought
osed from 60 to 150 days of crop age
olding irrigation in treatment plots (Fig.1). The
lusion of border rows and a gap of 3 m
treatment blocks (to minimize seepage effect). Soil

3. Rating for drought tolerance
The harvest index proposed by Donald was used as one of the criteria to
assess the potential yield and stability in different environments. The relative
performance of the genotypes in terms of cane yield and sugar yield was
assessed by plotting the cane yield under drought treatment against yield under
normal condition. Similarly, for sugar yield also relative performance was
worked out. The graph was constructed in such a way that the plot area of the
graph was divided into four quadrants by dividing the X axis at the point of mean
cane yield under normal condition and Y axis at the point of mean cane yield
under drought condition. Genotypeswith better cane and sugar yield in normal
as well as drought treatment falling in quadrant- I were considered as tolerant
types; genotypes falling in quadrant I1 & 111 were considered as moderately
tolerant, while genotypes falling in N quadrant were considered as susceptible
types.
Sugarcane genotypes tolerant to drought
Varieties CoC 671, Co 8208, Co 85007, Co 85004, Co 86032, Co 85019
and Co 87263 are suitable for 'water limited condition. AVT clones screened
during 2004 (Co 99004- Damodar) and 2006 (Co 2001-13 (Sulabh) and Co
2001-15 (Mangal) were recently released for peninsular zone (Fig. 2). New
promising drought tolerant genotypes also have been identified (Table 1).
Table 1. Drought tolerant aenatvws
VSI

4. Drought tolcmt wlctles