Genetic structure of population and association analysis of some morpho-physiological traits of bread wheat under salinity stress using Simple Sequence Repeats (SSR)

Association analysis of 105 bread wheat (Triticum aestivum L.) genotypes was carried out using 12 SSR markers. For this purpose, wheat seeds were planted in pots in a randomized complete block design with three replications under normal (10 mM NaCl) and saline (120 mM NaCl) conditions and the activity of catalase (CAT), ascorbate peroxidase (APX), and total protein contents were measured. The results of combined analysis of variance showed that the activity of catalase, ascorbate peroxidase, and total protein contents were significantly different in the bread wheat cultivars under study. The results of multiple regression analysis showed that gwm67b and gwm282d markers under salinity conditions were more correlated with catalase activity in the studied species. Also, gwm291a, wmc73a, and barc124a markers were the most effective markers in association with APX enzyme. Analysis of the population structure and the resulting plot showed that the K Index and the Average Likelihood Logarithm had the highest value at K =2 (57.38), thus the population under study has most probably 2 subpopulations. Tassel analysis of SSR markers under normal irrigation and salinity irrigation conditions obtained 54 loci related to the traits under study in control condition and 61 loci in salinity condition based on the general linear model (GLM) and also 35 related loci in control condition and 20 loci in salinity condition based on the mixed linear model (MLM)