Identification of genomic loci controlling phenologic and morphologic traits in barley (Hordeum vulgare L.) genotypes using association analysis

Association mapping is a technique with high resolution for QTL mapping based on linkage disequilibrium and has shown more promising for describing genetically complex traits. In addition, it is a powerful tool for describing complex agronomic traits and identifying alleles that can contribute to enhance the desired traits. In this study, whole genome association mapping was used in a set of 148 spring barley cultivars. Phenotypic evaluation was conducted at Zahak Agricultural Research Station, Iran, using alpha-lattice design with two replications, for two croppinhg cycle (2014-2015 and 2015-2016). Traits such as days to anthesis, days to physiological maturity, grain filling period, flag leaf length, flag leaf width, grain number per main spike, thousand grain weight and grain yield were measured. Association analysis between the markers and phenotypic traits was performed with a mixed linear model (MLM with K+Q). In total 28 QTLs were identified which were related to the measured traits. A stable QTL was detected on chromosome 5H (74.76 cM) for days to anthesis. Three QTLs were detected on chromosomes 4H (125.08 cM and 120.64 cM) and 5H (74.76 cM) for grain filling period. One QTL on chromosome 2H (10.87 cM) was associated with days to anthesis, grain filling period and 1000 grain weight. One QTL on chromosome 4H (125.08 cM) was also associated with days to anthesis, grain filling period as well as flag leaf length and 1000 grain weight. Common genetic locations for these traits could be due to pleiotropic effects or genetic linkage.