QTL mapping of grain yield and its components under normal and drought stress conditions in barley (Hordeum vulgare L.)

Abstract

A population comprising of 118 double haploids of barley derived from a cross, Nure x Tremois was evaluated for different traits for yield and its components under normal and drought stress conditions. Using a genetic map of 543 markers (DArT, SSR, SNP and AFLP), we identified 33 additive quantitative traits loci (QTLs) for phenological and morphological traits. All of these Qtls had additive and digenic effects. Five out of 67 epistatic Qtls exhibited significant Q×T interactions. The majorities of main effects were detected on chromosome 5H and affected primarily plant height (PH), number of spikes /plant (Ns/P), kernels per spike (KS), thousand kernel weight (TKW), main spike length (MSL) and harvest index (HI). We identified additive QTLs for plant height on most the chromosomes, except 4H. Five pairs of epistatic QTLs for plant height without interaction with environments were also detected. However, we did not find any additive QTLs for grain yield, but detected nine epistatic QTLs on all of the barley chromosomes. None of them had interaction with environments.