Molecular identification of Date palm (Phoenix dactylifera L.) "Deglet noor" pollinator through analysis of genetic diversity of Algerian male and female ecotypes using SSRs markers

Date palm (Phoenix dactylifera L.) "pollinator or dokkar" influences fruit's quality and quickness of maturity "metaxenia". This study characterizes the genetic diversity and the relationships between different Algerian ecotypes of dokkars. In addition, we report on the use of microsatellites to identify pollinators that are genetically the closest to "Deglet Noor" and "Ghars" cultivars. A total of 25 microsatellites were used on 50 accessions from Algeria, showed high genetic variability. The number of amplified alleles was 135 and ranged from 2 (PDCAT3) to 12 (DP 159), with an average of 5.44. The average of observed heterozygosity ranged between 0.026 (DP169) and 1.00 (PDCAT10, DP171, DP160, DP159, MPdCIR32 and MPdCIR10), with a mean of 0.688 indicating high diversity of date palm accessions. The average of expected heterozygosity was 0.436 and varied between 0.098 (PDCAT3) and 0.6 (PDCAT2). Almost Fis values were negative for markers except for DP 169. Unweighted Pair Group Method with Arithmetic Averages (UPGMA) clustering highlighted close genetic relationships between male and female genotypes for "Deglet Noor" accessions and showed case of homonymy and presence of clones. Principal Coordinate Analysis (PCoA) showed pattern that evidences the genetic diversity existing among pollinators that allowed distinguishing them easily. The combination of two SSR allowed to unambiguously distinguish six dokkars. Overall, UPGMA and PCoA showed that accessions of same type were clustered according to their origin (Oasis). Among the 28 private alleles scored in this study, nine were scored for "Deglet Noor". Bayesian analysis showed a conserved genetic structure mainly for "Deglet Noor". Our results suggest that specific SSR marker (MPDCIR35) that characterize both male and female individuals of "Deglet Noor", could be used as potential marker to select, at early stage of seedling, the closest pollinator to the female individual of this important commercial cultivar. In addition, MPdCIR25 represents potential marker to identify male individuals of "Ghars".