Studies on genetic divergence in cowpea (Vigna unguiculata) by using D2 statistics

The field experiment was carried out by using the 40 genotypes of cowpea during summer season, 2022 at the Department of seed technology, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar. Based on D2 analysis, these genotypes were grouped into 12 clusters. The material was evaluated in a randomized block design with four replications. The observations were recorded on 11 characters viz., leaf width, leaf length, time of flowering, days to maturity, pod length, number of pod per plant, number of seed per pod, number of primary branch, plant height and petiole length. Cluster pattern revealed that cluster I (11 genotypes) and II (10 genotypes) were the largest groups, followed by cluster 3 (4 genotypes), cluster 4 and cluster 5 (3 genotypes) and cluster 8 and 9 (2 genotypes). All other five clusters were composed by single genotype, indicating wide diversity from rest and also from each other. The maximum intra-cluster D2 value was shown by cluster V (19.14) followed by cluster IV (18.52), cluster IX (18.30) and cluster VIII (17.98). The maximum inter- cluster D2 values among genotypes existed between clusters IX and XII (144.23) followed by clusters X and XII (143.42), clusters X and XI (135.41). The genotypes belonging to clusters VIII recorded the high value for pod length, seed yield per plant and number of pod per plant.