Biodiversity of date palms (Phoenix dactylifera L.) in Sudan: chemical, morphological and DNA polymorphisms of selected cultivars

Date palm fruits of 15 cultivars were collected at harvest (Tamr stage) from the Nori Horticultural Orchard in the Northern State of Sudan for morphological and chemical characterization. Morphological and DNA polymorphisms of the mother trees were also investigated. Significant (P , 0.001) differentiation of cultivars in relation to tree height, and number and length of pinnae and spines was observed. Fruit weight, flesh weight and fruit and seed sizes expressed a wide range of diversity among cultivars. Significant differences were also observed among cultivars for all tested sugars (P , 0.001). Titratable acidity was found to be a characteristic feature of almost every cultivar. The results of DNA genotyping indicated high genetic diversity among cultivars with Nei’s genetic distances ranging from 0.693 to 3.496, and expected and observed heterozygosity equalling 0.837 and 0.950, respectively. This study highlights the diversity of date palms in Sudan, as represented by apparent morphological characters, chemical composition of fruits as well as DNA polymorphism. The employment of different techniques for data analyses gave conclusive ideas on some interrelationships among a large set of characters; the knowledge of such relationships can be utilized for screening date palm cultivars for possible descriptors.