Fifty Thai aromatic rice landraces and one commercial cultivar (KDML 105) were subjected to proximate nutritional analysis to determine protein, fat, fiber, carbohydrate, ash, moisture, amylose and 2AP contents. Genetic diversity was characterized using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) markers. Fifty-one cultivars were clustered based on RAPD and ISSR markers. Various nutrient compositions of the fifty rice landrace cultivars and one commercial cultivar were checked. Among 100 RAPD primers tested, 15 showed high polymorphism (100%) with an average of 21.2 bands per primer. Fifteen ISSR primers out of 100 produced high polymorphism (99.74%) with an average of 26 bands per primer. The UPGMA dendrogram based on genetic similarity grouped the cultivars into two clusters and several sub-clusters. Clustering of aromatic rice using ISSR markers gave increased clarity and was more effective than using RAPD markers for both nutritional composition and polymorphism level. Findings will provide practical guidelines for nutritionists and plant breeders in selecting suitable cultivars and genetically diverse parents for plant breeding programs
