Evaluation of diversity in selected populations of Iranian date palm (Phoenix dactylifera L.)  using ISSR markers

Abstract

Date palm (Phoenix dactylifera L.) is cultivated mainly in arid and semiarid regions of the south and southwest of Iran. Sixty-nine Iranian genotypes were selected from 13 populations. One Moroccan genotype was also included in the experiment. The genotypes were sampled in Azizabad agro-research station in Kerman province, Iran. The number of alleles per locus ranged from 5 to 10, totaling 65. Polymorphism information content (PIC) varied from 6 to 30%, averaging at 19.4%. The highest and lowest values of effective alleles were found in Kerman (Ne = 1.49) and Bushehr (Ne = 1.15), respectively. The highest value of the Shannon index (I = 40%) and polymorphic loci percentage (PL = 67.69%) were detected in the ‘Kerman’ population. A high degree of genetic diversity was found in the ‘Hormozgan’ population (He = 0.26). The highest correlation coefficient (r = 0.983) was observed between Kerman and Hormozgan. Based on Nei’s genetic identity, the first two principal coordinates (PCoA) showed that the populations of Fars, Morocco, and Bushehr were classified as three separate groups, unlike the Kerman, Hormozgan, Khuzestan, and Persian Gulf Basin (PGB) populations. In addition, bilateral charts and genetic relatedness among the genotypes were illustrated by STRUCTURE software, which divided the 70 date palm genotypes into seven groups. The grouping of genotypes did not correlate with their geographical distribution. Thus, the Q-values of the genotypes grouped most of them as mixed. It seems that a lack of clear separation among the genotypes was because of their shared genetic background. To assist in future crossing programs, our findings showed that ISSR markers prioritized several male stocks of date palm.