Abstract
Date palms are now grown extensively around the world. There are many cultivars such as Ajwa, Nabtet Ali, Rothanah, Barhi, and Sokkari dates, known for their superior quality. The Ajwa cultivar, however, has particular religious and medicinal significance. The aim of the study was to determine the sugar content of dates from five cultivars in Saudi Arabia. Also, genetic relationship of Ajwa cultivar collected from different locations to Ajwa cultivar from Madinah location. The results of sugar content proved that the dates of five cultivars were rich in sugar (56.60 - 83.75 % dry weight). Cultivar "Barhi" showed only monosaccharides. However, cultivars "Sukkari and Nabat Ali" contained the highest sucrose, a disaccharide, (47.7 and 33.3%). Cultivars "Ajwa and Rothans" showed lower content of disaccharide (22.94 and 10.5%) but higher level of monosaccharides (51.69 and 53.6%), respectively. Analysis of genetic relationships among the samples of Ajwa cultivar collected from different locations was studied using ISSR markers. On the basis of UPGMA analysis the samples were clustered into three clusters. The sample of cultivar Ajwa collected from location 'Al-meznib' did not markedly diverge from Ajwa cultivar (AL-madinah). Therefore, the polymorphism detected suggested that ISSR markers are reliable for date palm germplasm characterization.