Molecular approaches for wheat improvement under drought and heat stress

Abstract

Novel molecular breeding selection strategies were implemented in breeding programs in India for wheat improvement under drought and heat stress. Elite Indian varieties HD2733 and GW322 were targeted for improvement to abiotic stresses through marker assisted backcross breeding approach. Backcross populations were advanced to BC1/BC2 F2 after tracking QTLs for foreground selection covering traits such as canopy temperature (CT), chlorophyll content, normalized difference vegetation index (NDVI), grain filling duration (GFD), thousand kernel weight, grain yield and a range of polymorphic microsatellite markers covering entire genome (4-5 SSR markers per chromosome) being used for tracking the recurrent parent genome. Marker assisted recurrent selection (MARS) involved estimation of marker effects for several small effect/major QTLs followed by two recombination cycles. Designed intermating among selected F5 families were carried out after conducting ANOVA and AMMI analysis on multi-location yield trials and polymorphic markers among the parents in two biparental base populations (F5). Inter-family intermating
among the best identified families carried out in different combinations to accumulate and recombine 4-8 QTLs per intermated progeny and confirmed in selfed homozygous lines.