Harnessing potential grain traits from pre-breeding backcross introgression lines of wild emmer wheat

Grain size and grain weight are key productivity traits in wheat. The evolutionary lineage of cultivated wheat harbours haplotypes with fixed allele diversity leaving a limited genetic diversity for agronomic traits in modern wheat. But enormous variations for grain traits present in wild emmer wheat are unrealized and underutilized. The present investigation was planned to introgress novel alleles governing better alleles for traits of thousand grain weight (TGW), grain length (GL) and grain width (GW) from thirteen tetraploid accessions of wild emmer wheat (WEW) Triticum dicoccoides into five cultivated bread wheat varieties. The 196 backcross introgression lines (BILs) generated in current study had undergone intensive selection cycles for grain traits and yield performance for two backcross and 6 selfing generations. As a result, the distribution curve of BILs for traits was positively skewed and high mean for GL (6.7 mm), GW (3.1 mm) and TGW (36.25 g) was observed in BILs. TGW was significantly positively correlated with GL (0.60, p < 0.001) and GW (0.66, p < 0.001). The 196 BILs were genotyped with SSR markers and introgression of WEW genome in different BILs varied from 4 to 40%. A total of 8 BILs were finally selected from different crosses based on their consistence performance for high GL, GW and TGW in hexaploid background over years. The pre-breeding material generated in the present study houses huge amount of diversity from WEW and will be instrumental in wheat breeding programmes aimed at improving yield.