Association analysis for yield and plant characteristics in Iranian flax genotypes (Linum usitatissimum L.) using IRAP and REMAP markers

The identification of polymorphic markers associated with various quantitative traits allows us to test their performance for the exploitation of the extensive quantitative variation maintained in gene banks. In the current investigation, 7 IRAP and 13 REMAP primers and mixed linear model (MLM)-based association analysis was used to identify molecular markers associated with 20 agro-morphological traits in cultivated flax (Linum usitatissimum L.). Agro-morphological traits studied, were plant height, primary stem weight, secondary stem weight, number of primary branches, number of secondary branches, number of capsules per primary stem, number of capsules per secondary stem, weight of primary stem capsules, weight of secondary stem capsules, leaf weight, thousand seed weight, grain yield, biological yield, harvest index, days to growing, days to flowering, days to capsuling, oil, protein, and nitrogen percentages. Analysis of population structure revealed two possible subgroups (K=2) in the studied population. Fst mean values of the groups were relatively high, indicating remarkable differentiation among the groups. Association analysis using mixed linear model (MLM) identified 21 loci significantly (p < 0.01) associated with agro-morphological traits. The maximum number of associated loci was identified for leaf weight. LTR1833-LTR1868-3 marker was associated with harvest index, protein and nitrogen percentage. The results of the current study could be as a starting point for using MAS in flax breeding programs.