Molecular variability and genetic relationships of date palm (Phoenix dactylifera L.) cultivars based on inter-primer binding site (iPBS) markers

Abstract

Date palm (Phoenix dactylifera L.) is an important fruit crop in many arid areas and understanding the relatedness among genotypes is important for effective date palm improvement. Inter-primer binding site (iPBS) markers were used to assess the molecular variation and genetic diversity of 54 and 12 date palm (Phoenix dactylifera L.) genotypes collected from Australia and Iraq, respectively. The main objectives were to survey genetic diversity and to determine varietal differences among the collected date palm germplasm. The PCR of five iPBS primers (dominant markers) selected from an initial 60 produced a total of 111 bands ranging from 180 to 3500 bp. The PIC value for these five primers ranged from 0.2135 to 0.3289 with a mean value 0.2816. The mean expected heterozygosity (0.218), mean unbiased expected heterozygosity (0.229) and Shannon’s information index (0.33) indicated a high level of inbreeding among the accessions tested. Ordination and cluster analysis showed that the genetic relationships among all accessions could be separated into geographic origin; specifically Iraqi female cultivars, exotic female cultivars collected in Australia and male accessions also collected in Australia, with a few exceptions. Date palm accessions collected in Australia and Iraq are highly divergent and the abundant genetic diversity observed provides a beginning platform for date palm improvement in Australia. The iPBS PCR-based genome fingerprinting technology used in this study is low-cost and effectively differentiated accessions of date palm and their related species.