Genome-Wide Composite Interval Mapping Reveal Closely Linked Quantitative Genes Related to OJIP Test Parameters under Chilling Stress Condition in Barley

Abiotic stressors such as cold temperatures have intensified due to climate change. Cold stress is a crucial factor that restricts the growth of barley in tropical and subtropical regions. Fast chlorophyll a -fluorescence induction (OJIP test) parameters are also used as biological markers for screening cultivars tolerant to abiotic stresses. Therefore, an experiment was conducted over three growing seasons in the research farm of Gonbad Kavous University to identify closely linked quantitative trait loci (QTLs) controlling OJIP test parameters under chilling stress, in the Iranian barley RILs population. For this study, the genome-wide composite interval mapping method was utilized to identify closely linked QTLs associated with OJIP test parameters under chilling stress conditions. Combined analysis of variance showed that the lines had significant differences ( p < 0.05) in terms of OJIP test parameters, indicating genetic diversity among the lines. Also, Pearson correlation coefficients showed that grain yield had a significant positive correlation ( p < 0.05) with Fm, Fv, ABS/CSm, ETo/CSo, ETo/CSm, REo/CSo, REo/CSm, TRo/CSo and TRo/CSm parameters under chilling stress conditions. Cluster analysis using the WARD method identified 50 lines tolerant to chilling stress. A total of 48 stable and closely linked QTLs related to 12 OJIP test parameters were identified on seven barley chromosomes under chilling stress conditions.