Identification of novel and stable genomic regions associated with barley resistance to spot form net blotch disease under different temperature conditions during the reproductive stage

Spot form net blotch (SFNB) is one of the most important barley diseases in the world; abiotic stresses caused by climate change are also a problem for cultivation of cereals, including barley, on a global level. Identifying stable genomic regions associated with resistance to SFNB in different temperature conditions at the reproductive stage can accelerate the process of producing new cultivars resistant to this disease. In this study, 103 F-8 lines, resulting from the cross of cultivars Kavir and Badia, were cultivated in three years on three different dates. After artificial inoculation with Pyrenophora teres f. maculata Gonbad Kavous isolate, the plants were evaluated at the adult stage. The planting dates were chosen so that during early, conventional and delayed planting dates, the reproductive stage of the lines coincided with cold, non-thermal and heat stress conditions, respectively. A genome-wide composite interval mapping method was used to identify quantitative trait loci (QTLs) controlling SFNB and estimate the effect of each of them. In the cold, non-thermal and heat stress conditions at the reproductive stage, three (three major), four (two major) and six (one major) stable resistance QTLs against SFNB were detected, respectively. The stable QTLs of resistance including QRPtma-2H, QRPtma-3H and QRPtma-7H were located on chromosomes 2H, 3H and 7H, respectively. After flanking markers confirm the resistance of QTLs to SFNB, the SCoT7-C, ISJ17-B and Bmac0144k markers can be used in the screening resistance of cultivars under non-thermal and heat stress conditions. Moreover, the Bmac0282b and Ebmatc0016 markers can be used for screening resistance of cultivars under cold stress conditions in marker-assisted selection projects.

Automated summary

This study identified stable genomic regions associated with resistance to spot form net blotch (SFNB) under different temperature conditions. The QTLs for SFNB resistance were detected in cold, non-thermal, and heat stress conditions, with three, four, and six stable QTLs respectively. Flanking markers SCoT7-C, ISJ17-B, and Bmac0144k can be used for screening resistance to SFNB under non-thermal and heat stress conditions, while markers Bmac0282b and Ebmatc0016 can be used for screening resistance to SFNB under cold stress conditions.