Assessment of salt tolerance potential at the germination and seedling stages in pigeonpea (Cajanus cajan L.)

Identification of salt-tolerant genotypes and their subsequent utilization in producing salt tolerant varieties would be the most appropriate and cost-effective strategy for improving the yield of pigeonpea (Cajanus cajan L.) in salt-affected areas of the country. The present study assessed fifty diverse pigeonpea genotypes for their responses to salt (NaCl) concentrations of 60, 80 and 100 mM at seed germination and seedling stage (21-days-old). The tested genotypes were assessed for their changes in 11 morpho-physiological traits under salt stress and the phenotypic scores of the genotypes were analyzed statistically. Statistically, significant variations were observed among the genotypes for all the morpho-physiological traits under study including the germination percentage and seedling survivability. The genotypic and phenotypic correlation among the traits and the Principal Component Analysis (PCA) revealed that the seedling stage of the crop and 80 mM Nacl concentration are optimum for identifying pigeonpea genotypes tolerant to salt stress under controlled conditions. Out of the 50 genotypes, 10, namely, BDN-708, AKTM 16-41, AKTE 16-09, JKM-7, TV-1, BDN-716, PT 0607-5-1, JKM-189, Phule Rajeshwary, BDN-711 and AKTE-12-04 were found to be tolerant to salt stress and rest were sensitive. The salt tolerant genotypes clustered together under UPGMA, indicating their genetic relatedness for the trait. The salt tolerant genotypes identified in this study would be useful in the development of a mapping population for mapping the salt stress, and breeding for high-yielding pigeonpea varieties with tolerance to salt stress.