Detection of exotic alleles for important agronomical traits introgressed from Hordeum vulgare ssp. spontaneum under drought stress

Drought stress is a major constraint for barley production and yield stability in rainfed ecosystems. An advanced backcross breeding strategy was used to identify quantitative trait loci (QTLs) associated with yield and yield components in a BC3 population derived from an interspecific cross between six-rowed spring barley (H. vulgare) ‘Azhul’ and wild barley (H. spontaneum) line ‘Spontaneum I’، under drought stress. The linkage map constructed by 170 SSR molecular markers covered a total length of about 1008. 7 cM. For ten agronomical characteristics، 27 QTLs were determined. The phenotypic variation explained by individual QTLs ranged from 5. 7% to 34. 8% and the LOD scores ranged between 3 and 12. 4. A total of 12 new QTLs were identified، where at ten QTLs the exotic introgression caused an improved trait performance، under drought stress. Four QTLs contributed by ‘Spontaneum I’ on chromosomes 1H، 2H، 3H and 7H were found to significantly increase chlorophyll content، days to maturity، flag leaf length and number of tillers per spike، respectively. In conclusion، the results of this study showed that Hordeum spontaneum، the wild progenitor of barley، is a potential source of useful genetic variation for barley breeding programs.