Phenotypic and genotypic evaluation of Hordeum spontaneum derived lines for adaptation to drought stress conditions: an international collaboration between ICARDA and Australia

Barley is one of the most important crops in many developing and some developed countries, such as Australia. In these countries, barley yield is largely affected by drought, which can be as severe as to cause crop failures. Wild barley is a potential source of useful genes for the development of improved varieties with good adaptation to drought stress. The objective of this work was to test the hypothesis whether specific chromosomal regions of H. spontaneum are responsible for the adaptation to drought. Fifty-nine barley lines carrying various levels of introgression from H. spontaneum were tested in replicated field trials, under low rainfall conditions in Syria, and genotyped with 50 simple sequence repeats (SSRs). The amount of variability between the wild barley derived lines and improved varieties was relatively high for important developmental and yield related traits. The best performing wild barley derivatives out yielded the Syrian improved landrace variety Tadmor by 7.2-23.8% and the Australian feed barley varieties Keel and Barque by 5.2-17.1% in the location (Breda) where drought stress was most severe. The molecular analysis using SSR markers revealed that chromosomes 1H, 2H, 3H, 4H and 7H had the highest percentage of shared alleles with H. spontaneum, linked to important yield and developmental traits. SSR markers 14079 (55.9%) followed by Bmac0581 (54.2%) and Bmac0213 (49.2%) contributed the highest percentage of shared alleles. The performance of wild barley derived lines suggests that H. spontaneum is a useful source of genes for the improvement of cultivars better adapted to low rainfall environments.