Genetic diversity of flax genotypes (Linum usitatissimum L.) by using agro-morphological properties and molecular markers

Flax is one of the significant crops owing to oilseed and fibre attributes, exhibiting a wide distribution in many parts of the world. In this regard, we collected 29 genotypes of the flax from the different sources including agricultural institutes and research centers in Türkiye. We, for the first time, screened the genetic diversity and population structure of 29 flax genotypes using both 12 inter-primer binding sites (iPBS) and 33 inter simple sequence repeats (ISSR). In addition, some morphological traits of the genotypes were also determined. According to the unweighted pair group method with arithmetic mean (UPGMA)-based dendrogram, genotypes of the flax were classified into the two major groups (A and B). Group B was composed of two sub-groups (B1 and B2) according to the six phenotypic attributes considered for analysis. Concerning molecular relationships of the genotypes, individual and combined UPGMA-based dendograms were constructed with respect to the ISSR and iPBS markers. According to the Jaccard similarity coefficients for ISSR data, flax genotypes were divided into two main groups (A and B) and the “Van-1” genotype was in group A alone. Also, group B was divided into two separate subgroups. “Afyon-1” and “İzmir-Kemeraltı” genotypes were located in group B1, while all the remaining genotypes were located in group B2. In addition, the average genetic similarity was 0.755 regarding the findings of iPBS-retrotsposon markers, flax genotypes were classified into two main groups (A and B), and these main groups formed two subgroups among themselves. While “Konya-1” is located alone in A1 subgroup, “Iğdır”, “İzmir-Kemeraltı”, “Mardin”, “Bitlis” and “Afyon-1” genotypes were located in A2 subgroup. While “Van-1” genotype was located in the B2 subgroup alone, other genotypes were found in the B2 subgroup. The average genetic similarity was determined as 0.578 according to Jaccard binary similarity coefficient. According to the combined data of two markers, two separate groups (A and B) were revealed, similar to the dendrogram constructed with ISSR data. “Van-1” genotype was located in group A alone. Group B was divided into two subgroups (B1 and B2). The average genetic similarity was 0.722 according to the Jaccard similarity coefficient of matrix. Concerning the values of agro-morphological traits, the values of the parameters ranged as follows: technical stem length (19.32–45.39 cm), technical stem fresh weight (0.13–0.82 g), root length (4.07–7.84 cm), and root fresh weight (0.03–0.13 g). These variations were statistically significant between the genotypes. As being characterized with fibre use; specifically, the highest technical stem length was observed for "Ankara-Çankaya", while the lowest height was recorded for “Royal”. Overall, regarding discrimination of genotypes; agro-morphological attributes were consistent with the genetic diversity and population structure obtained with iPBS-ISSR markers. Furthermore, Mantel analysis revealed that the correlation coefficients between ISSR and iPBS were high and significant. However, the correlation between phenotypic characteristics and those two marker systems was low and this correlation was significant for ISSR marker.