Genetic diversity in palmyrah genotypes using morphological and molecular markers

Palms are woody monocotyledons in the family Arecaceae which is placed in the order Arecales. Slow and tall growing, hardy and non branching, dioecious and perennial in nature, palmyrah palm has no distinguishing features to identify sex, stature and high neera yielding types until flowering age of about 12 to 15 years. Under these circumstances molecular markers can be effectively utilized to diagnose and select a genotype. Twenty palmyrah accessions were analysed using RAPD and ISSR markers. In RAPD analysis, a total of 57 bands were obtained, among them 43 were polymorphic and rest of them were monomorphic. Amplification size ranged between 250 and 3200 bp. UPGMA based cluster diagram showed that all 20 different genotypes were grouped into four different clusters based on the stature, sex and high neera yielding types. The distance matrix between genotypes showed an average distance range from 0.54 to 0.91 with a mean of 0.70. A total of 130 ISSR markers were scored, of which 65 were polymorphic, equivalent to 47.94% polymorphism. These markers were used to estimate the genetic similarity among accessions using Jaccard’s similarity coefficient, with similarity values ranging from 71.6 to 95.7%. The average number of markers produced per primer was 6.11. For each of the 21 ISSR primers PIC value ranged between 0 and 0.46. Cluster analysis based on ISSR data grouped the 20 palmyrah accessions into two major clusters. PCA based on ISSR data clearly distinguished genotypes similar to the results of cluster analysis.