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Sugarcane Breeding lnstltuto (Indian Council of Agricultural Resemh) -I

~ t o r e - 6 4 l a n ~ ;, I

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 identifying resistant 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

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. Genotypes with 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

Drought tolcmt wlctles