Status and genetic diversity in pigeonpea germplasm from Caribbean and Central American regions at ICRISAT genebank

The genebank at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, India holds a collection of 542 accessions from the Caribbean and Central American (CCA) regions, of which 424 were evaluated for eight qualitative and 17 quantitative traits at ICRISAT farm. A hierarchical cluster analysis was performed using the scores of the first nine principal components that resulted in four clusters. The accessions of these four clusters exhibited the following good characteristics: cluster 1 had high pod-bearing length and high seed protein content; those of cluster 2 had high degree of branching, large number of pods per plant and high seed yield per plant; those of cluster 3 had long pods; and those of cluster 4 had larger seeds. In the whole collection of accessions, diversity was found to be maximum (H' = 0.630 + 0.026) for plant height and minimum for tertiary branches per plant (H' = 0.259 + 0.026). The highest correlation coefficient was observed between racemes per plant and pods per plant (r = 0.914) followed by between pods per plant and seed yield per plant (r = 0.744), and between shelling percentage and the harvest index (r = 0.703). In view of the poor representation of the world collection of pigeonpea (13,771 accessions) from the CCA regions, launching of collection missions in these countries has been suggested to fill gaps and increase the variability. Multi-location evaluation of the collections for agronomic traits at potential locations in the CCA regions and systematic evaluation for nutritional traits and resistance to biotic and abiotic stress could result in the identification of useful genotypes, particularly vegetable types, for use in breeding programmes to develop high-yielding cultivars as well as to release as varieties in these regions.