Molecular and morphological diversity among the cluster bean [Cyamopsis tetragonoloba (L.) Taub.] genotypes

Cluster bean [Cyamopsis tetragonoloba (L.) Taub.] is an important vegetable crop of industrial importance known as gaur, it is a self-pollinating and deep rooting crop, thus it is well adapted to semi-arid and arid rainfall areas. This legume crop is being grown for wider uses like human food, animal feed as well as fodder, and also for industrial uses for galactomannan gum extraction from a commercial perspective. In the crop genetic improvement is being limited, which could be due to insufficient diversity, or lack of exploitation of genetic resources. Therefore, we collected 70 gaur genotypes and were employed to estimate the genetic diversity along with four varieties using simple sequence repeat (SSR) markers. The PIC value ranged from 0.05 to 0.62, with an average of 0.38, while SSR marker amplification with 23 polymorphic primers detected 99 alleles with a mean of 4.30 alleles per SSR marker. Three separate groups emerged from the clustering analysis. Furthermore, twenty-four morphological traits were studied for the analysis of morphological diversity, and the genotypes and varieties were divided into eight subgroups based on standardized morphological data based on Mahalanobis D-2 statistics. Cluster IV had the greatest intracluster distance (D-2 = 7698.63), and clusters IV and VIII had the greatest intercluster distance (D-2 = 195,694.80). Thus, the study revealed that collected genotypes contain a wide range of diversity, and the molecular markers can be utilized in conjunction with morphological characterization for a better description of the level and pattern of genetic diversity, as well as for the cluster bean breeding and improvement programs.

Automated summary

In this study, genetic diversity and morphological diversity of 70 cluster bean genotypes were evaluated using SSR markers and morphological traits analysis. The results showed that the collected genotypes contained a wide range of genetic diversity. Molecular markers and morphological traits could be used to better describe the level and pattern of genetic diversity, and provide a basis for cluster bean breeding and improvement programs.