Currently, the identification and characterization of date palm varieties rely on a small number of morphological traits, mainly of fruit, which are complex and greatly influenced by the environment. As a result, different varietal names may actually refer to the same variety while different varieties may have the same name. Therefore, new descriptors like molecular markers are required to identify, characterize, and estimate genetic diversity in this crop. Here we used amplified fragment length polymorphism (AFLP) markers to discriminate 18 Iraqi date palm varieties and to estimate the genetic relationship among the varieties. A total of 122 polymorphic AFLP loci were scored, with an average of 17.4 polymorphic loci per primer combination. The use of any one of the four combinations, P101(aacg)/M95(aaaa), P74(ggt)/M95(aaaa), P73(ggg)/M95(aaaa), or P100(aacc)/M95(aaaa), was sufficient to uniquely identify all the varieties. Jaccard's genetic similarity index ranged from 0.108 to 0.756, indicating moderate to diverse relationships. Estimation of average proportion of fixed recessive AFLP loci indicated that most of the loci in variety `Chipchab' were fixed, whereas most of the loci in `Jamal Al-Dean' could be heterozygous and in-between in other varieties. Unweighted pair group method with arithmatic mean (UPGMA) analysis ordered the date palm varieties first into two broad groups at 27% similarity levels. One group consisted of seven varieties and the second group consisted of the remaining 11 varieties of date palm. These results showed that the AFLP technique is an efficient method for varietal identification and estimating genetic relationships in date palm.
Jaladet M.S. Jubrael, Sripada M. Udupa and Michael Baum
Hussam S.M. Khierallah, Saleh M. Bader, Michael Baum and Alladin Hamwieh
Genetic diversity in 30 date palm (Phoenix dactylifera L.) cultivars in Iraq representing 24 female and six male cultivars was investigated using 22 microsatellite [simple sequence repeat (SSR)] primers. The tested SSR markers showed a high level of polymorphism. A total of 188 alleles were detected at the 22 loci ranging from three to 21 with an average of 8.54 alleles per locus. The average of heterozygosity for all cultivars was 0.503; genetic distance among cultivars varied from 0.171 to 0.938 indicating diverse relationships. The cultivar Ghanami Akhder was highly divergent from ‘Ghnami Ahmer’, whereas ‘Jamal Al-Dean’ was very closely related to ‘Qitaz’. Unweighted pair group method arithmetic average ordered date palm cultivars into two main clusters. Principal coordinate analysis exhibited the similar clusters of cultivars as in the dendrogram.