Marker assisted stacking of drought tolerance QTL and rust resistance genes in an elite Indian wheat genotype

Abstract

Backcross population derived from a cross between Triticum aestivum advance breeding line PBW703 (PBW343+Lr24+Lr28+Yr10+Yr15) and Babax, a drought tolerant line from CIMMYT was used for introgression of drought tolerance QTL (quantitative trait loci) regions in a leaf and stripe rust resistant background. Out of 24 polymorphic SSR markers reported to be linked to drought tolerance in earlier studies and 15 markers showed introgression on different chromosomes with minimum of two and maximum of nine introgressed regions in different BC2F1 plants. For phenotypic analysis, 364 BC2F4 progenies from best performing selected BC2F1 plants were evaluated for rust reaction, chlorophyll content, canopy temperature, stay green, plant height, number of tillers per meter, number of spikelets per spike, number of grains per spike, 100 grain weight under restricted irrigated conditions. Correlation analysis showed that there was significant and positive correlation between these morphological traits. Transgressive segregants were observed for all the traits which were out performing the recipient parent PBW703. A total of 42 plants carrying the Babax specific alleles for drought tolerance QTL and all the four rust resistance genes Lr24, Lr28, Yr10 and Yr15 were finally selected for agronomic evaluation. Selected improved lines for drought tolerance are being evalauted in the wheat breeding programme.