Identification of genomic regions associated with net blotch resistance in barley

Barley net blotch caused by the fungus Pyrenophora teres is a major barley disease in Iran. Identification of genomic regions associated with net blotch resistance could accelerate the process of producing new resistance cultivars. For this study, a population of 142 two-row spring barley cultivars was used for association mapping analysis using 407 SSR and AFLP markers. Phenotypic data were also obtained from disease evaluation in two seedlings and adult plant stages. Seedling (with an isolate of spot form net blotch) and adult plant stage evaluation respectively, under control conditions of Mashhad Agricultural Research Station (Toroq), and the field of Araqi Mahale Agricultural Research Station (Gorgan) during 2016-17 and 2017-18 cropping seasons. Results showed that respectively 83 and 80% of cultivars were semi-susceptible to susceptible in seedling and adult plant stage. Population structure analysis subdivided the studied cultivars into two subpopulations (K=2). The results of association mapping analysis for seedling and adult plant stages revealed that six and 13 QTLs associated with disease resistance were identified, respectively, that accounting for 2.9 (QRpts6H) -18% (QRpta4H) of the genetic variation. Four markers––E38M50-119, E38M50-355, E38M50-390, E35M54-163––were common in both growth stages. Detection of these markers could help in more detail understanding on the genetic architecture of resistance to net blotch and development of diagnostic molecular markers and be a prelude for more detail understanding of research into the candidate regions identified in the barley genome.