Characterization of released and elite genotypes of guar [Cyamopsis tetragonoloba (L.) Taub.] from India proves unrelated to geographical origin

Twenty-three released and elite genotypes of guar [Cyamopsis tetragonoloba (L.) Taub.] from different parts of India were subjected to morphological, biochemical and molecular characterization. The major objective was to study the extent of genetic variability amongst different genotypes of guar, their grouping and identification using combination of phenotypic, biochemical and molecular markers. Phenotypic characters revealed the presence of ample amount of variation in cotyledon size, root length, hypocotyl length, epicotyl length, pubescence, plant height, leaf margin, branching habit, growth habit, days to 50 % flowering, days to maturity, flower colour, pod size, number of pods per cluster and number of clusters per plant for all the 23 genotypes. Biochemical studies including peroxidase activity along with phenol, potassium hydroxide and gibberellic acid tests also produced significant variability among the genotypes. A total of 180 amplified bands were detected using 21 RAPD primers, out of which 178 were polymorphic. The genotypes revealed high genetic divergence with similarity indices ranged from 0.59 to 0.85. A clear relationship between genetic diversity and geographical location was not observed. Fingerprints generated in the present study, using morphological, biochemical and molecular markers, successfully categorize the different guar genotypes into various groups and also establish relatedness among them based on the genetic diversity. This work will help the breeders working in the country for crop improvement of guar in characterization, identification, determination of seed purity and parental selection.