Analysis of molecular marker-based characterization and genetic variation in date palm ('Phoenix dactylifera' L.)

Abstract

Date palm breeding is challenging because of its long juvenility and dioecity. Genetic variation between cultivars is a pre-requisite to develop improved varieties. DNA fingerprinting is an effective method for date palm cultivar identification, examining genetic diversity and phylogenetic analysis. This review discusses the different markers used in DNA fingerprinting and phylogeny analysis of date palm varieties and the advances achieved. The date palm fingerprint analyses reported so far are neither comprehensive nor particularly clear because of variable variety nomenclature, a large number of uninvestigated new introductions, and uneven geographic sampling, which itself leads to inconsistent nomenclature. Most of the molecular markers utilized such as RAPD, RFLP, AFLP, ISSR and SSR have some limitations related to their cost, ease of use, robustness, dominance/co dominance and polymorphism level. Nuclear Microsatellite or (SSR) markers seem to fulfill most of the requirements to achieve accurate analysis of date palm fingerprints and phylogeny. The need for coordinated international, or at least regional, efforts to establish a comprehensive DNA fingerprint data set and phylogeny of all date palm cultivars is discussed in this review.