Evaluation of molecular diversity of durum wheat genotypes using RAPD and ISSR markers

Knowledge of the amount of genetic diversity in germplasms provides plant breeders with valuable information for the effective preservation of genetic resources and their use. More knowledge about genetic diversity and genetic factors of diversity is very beneficial for exploring new genes. Maintaining such diversity and using it in breeding programs is one of the main principles of biological conservation and genetic breeding of crop plants.

This research was conducted to evaluate the genetic diversity in 20 different durum wheat genotypes, including landraces, improved cultivars, and breeding lines using RAPD and ISSR molecular markers. In this research, 31 RAPD primers and 13 ISSR primers were used to evaluate the genetic diversity in durum wheat genotypes.

Based on the results, the studied genotypes had significant diversity based on both molecular markers. In RAPD analysis, 31 primers amplified 319 bands, of which 204 bands were polymorphic and the percentage of polymorphic bands was estimated at 63.94%. In ISSR markers, 13 primers produced 125 bands, of which 88 bands were polymorphic and the total percentage of polymorphic bands was estimated at 70.4%. Genetic similarity and cluster analysis of RAPD and ISSR were estimated using the Jaccard coefficient. For RAPD, the similarity index values ​​ranged from 0.22 to 0.90, and for ISSR from 0.22 to 0.94, which indicated the presence of high genetic diversity at the molecular level for the studied genotypes. The results of cluster analysis and principal coordinate analysis based on each of the RAPD and ISSR markers grouped genotypes into four groups. The results of the research showed that RAPD and ISSR markers are suitable markers for genetic diversity studies in durum wheat. But the ISSR marker is preferable due to its greater compatibility with the geographical origin, high reproducibility, and the similar cost as RAPD. The results showed that the grouping patterns of durum wheat genotypes are not mainly due to their geographical origins. The results indicated that the grouping of populations in different geographical regions in similar groups is probably due to the gene flow between regions through the gradual exchange of grains between farmers. This could also be due to the previous selection for sum agronomical traits in the populations for tolerance to environmental stresses.

Based on both markers, genotype # 20 (Stj3//Bcr/lks4) showed a different response from the other genotypes, so it was placed in a separate group in the analysis based on each of the markers. Therefore, this genotype can be used as one of the parents in crossing with other genotypes in subsequent studies.