Advanced backcross-quantitative trait loci mapping of grain yield, heading date, and their stability parameters in barley across multienvironmental trials in Egypt

Exploring the relationship between grain yield and heading date traits and their stability parameters at phenotypic, genetic, and molecular levels is the milestone for improving yield and adaptation in barley. We evaluated a mapping population comprising 298 doubled haploid lines in multienvironmental trials in Egypt. Composite interval mapping revealed 35 quantitative trait loci (QTLs) with four pleiotropic QTLs. A major QTL bPb-9110 (140.3 cM on 3H) with a peak LOD greater than 24 was found to be associated with the stability statistics b(i) and R-2 of heading date. Additionally, the marker bPb-1213 on 1H was correlated to heading date, grain yield, and the statistic b(i) (GYP). We also found that the gene HvFT4 (2H, 66 cM) had a significant impact on the heading date due to the presence of exotic alleles. This gene was closely linked to the photoperiod Ppd-H1 gene by 24.9 cM, and both genes play a major role in regulating flowering time in barley. Our results provide evidence that stability statistics pinpoint genetic control and appear promising for marker-assisted selection.

Automated summary

By evaluating a mapping population of 298 doubled haploid lines in multienvironmental trials, our study identified 35 QTLs related to heading date and grain yield traits, with four of them being pleiotropic loci. The results demonstrated that several key QTLs and genes play crucial roles in barley yield and adaptation.