Genetic variance between some Egyptian Date Palm cultivars using PCR-based markers with emphasis on the prevalence of Al wijam disease

Abstract

Date Palm is one of the most important crops in Egypt. At present, Egypt ranked second in world date production. The objectives of this study are the identification the genetic variance between some local varieties of Date Palm, in line with the establishment of a molecular diagnostic method to study the aetiology and the prevalence of Al Wijam disease. Date palm plantations have been suffering from number of pests and diseases infestation, mainly due to Dubas Bug, Red Palm Weevil, Lesser Date moth, and Al Wijam disease. Genomic DNAs were extracted from 18 Date Palm cultivars collected from Date Palm Research Institute, ARC using three different extraction methods. Nine common cultivars (Zaghlool, Hayani, Oraibi, Samani, Sultan, Bent-Aisha, Amrey, Aglani, and Barhee) and nine Siwi cultivars (Siwi, Fryhee, Taktakt, Quaipe, Karama Ghazally, Helw Ghanem, Gorm Agazal, and Oshbeigel,) were used in this study. In order to determine the genetic polymorphism and discriminate between each of these cultivars, RAPD and ISSR analysis were conducted on the isolated DNA samples from each cultivar. DNA fingerprints of the studied cultivars were conducted using 10 RAPD and eight ISSR primers. Dendrograms representing genetic relationships as well as genetic similarity matrices were performed for the studied cultivars using the UPGMA (Unweighted Pair Group Method with Arithmetic Average). Furthermore, 40 date palm trees representing the studied cultivars were collected from El-Marazik, El-Badrasheen, El-Wahat, and Demiate Governorates to study the prevalence of Al-Wijam disease using the DNA hybridisation technique. Symptoms including retardation in terminal bud growth, whole crown of leaves (rosetting symptoms), and yellow longitudinal lines on the midribs were observed. Non-radioactive Dig-labeled probes specific for 16s rDNA region of virus like agents were used to detect the infected trees.