Genetic and environmental variation among Qatari date palm cultivars assessed by DNA markers

Abstract

Date palms are generally propagated by separating the offshoots produced by individual trees. This method maintains the genetic integrity of date palm cultivars. However, well known date palm cultivars that are grown in different environments show little differences in fruit morphology and quality such as color and sweetness. The objective of the present research project is to analyze the genetic diversity among most common cultivars of Qatari date palms as well as the genetic variation within each cultivar grown in different environments in Qatar. Samples of the five most common date palm cultivars in Qatar; Khalas, Sheshy, Rezezy, Barhee and Khanezy were collected at three locations with different environments Al-Shamal, Al-Khour and Al-Rayan, Qatar. For each cultivar, samples were collected from three trees that showed little variation in their fruit morphology and quality. Genetic similarity or diversity among and within these cultivars was then analyzed using Inter Simple Sequence Repeat (ISSR) markers. A total of 18 ISSR single primers were used to amplify DNA bands using genomic DNA from the date palm samples. All of the primers used have amplified polymorphic bands in the studied cultivars either among the cultivars or within each cultivar in different cultivated environments. The results indicate the existence of genetic variations among the studied cultivars. Moreover, trees of the same cultivar that are grown in different environments show different DNA banding patterns explaining the variation in morphological and quality characters within each cultivar.