Genetic diversity analysis of tropical sugar beet (Beta vulgaris L.) varieties in Bangladesh using RAPD markers

Knowledge on intra-specific genetic variation of an organism is important for its genetic improvement and conservation. In order to estimate genetic variation and relatedness in eleven tropical Sugar beet varieties we used randomly amplified polymorphic DNA (RAPD) markers. The RAPD analysis was performed using six decamer random primers, which amplified a total of 63 DNA fragments of which 43 (68.25%) were found polymorphic. The average polymorphic bands per primer was 7.17 and the overall gene diversity was 0.24. Among the 43 polymorphic loci studied, 2 were specific for 2K 310, 1 for Shubraha, 1 for Natura and 1 for HI-0473 varieties. Pair wise genetic distance and similarity indices were ranged from 0.12-0.51 and 66.73-92.91, respectively. Cauvery and 2K 310 were found to be the most distantly related with a higher genetic distance value (GD = 0.51) and lower similarity index (SI = 66.73), while Aranka and Serenada were the most closely related with their lower GD (0.12) and higher SI(92.91) values. In an unweighted pair group method of arithmetic mean dendrogram constructed on the basis of genetic distances, the eleven varieties grouped into two main clusters: 2K 310 alone was in one cluster whereas 10 other varieties grouped into a major cluster. This indicates that 2K 310 was distantly related with each of the other varieties. Distantly related varieties based on estimated genetic variation could be selected for future breeding program that could result in improvement of this crop