Author(s):

Valarmathi M, Muthukumar M, Rahman H, Sasikala R and M Raveendran

Abstract: Drought is one of the major constraints limiting rice production and most of popular mega varieties of Tamil Nadu are highly susceptible to drought. Developing drought resilient rice cultivars will help in sustaining rice productivity under marginal environments. With the view to develop early maturing, drought tolerant rice lines possessing superior grain quality, a RIL population was developed between popular drought susceptible rice genotype Improved White Ponni and drought tolerant rice genotype Apo. Genotyping in F2 population using SSR markers linked to mega effect QTLs of Apo resulted in the identification of progenies harboring various combinations of drought tolerant QTLs. Two early maturing progenies namely #76 and #110 possessing high yield potential and superior grain quality were found to harbor 2-3 mega effect QTLs of Apo. QTL positive lines were further advanced up to F6 generation. About 159 F6 progenies were evaluated during January’2015 under field conditions for earliness, yield and grain quality traits which resulted in the identification of superior single plants of # 76 (3 QTLs) # 110 (2 QTLs) possessing early duration (< 110 days), high yield and good grain quality. These progenies were named as CBMAS14076 and CBMAS14110. CBMAS14076 and CBMAS14110 were evaluated for their drought responses under both greenhouse and field conditions along with IWP and Apo. Both these lines were found to be early (100 – 110 days) and exhibited improved drought tolerance when compared to IWP. IWP showed 23.3% reduction in single plant yield under drought; whereas CBMAS14076 and CBMAS14110 showed only around 16% reduction in single plant yield.

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