Evaluation of seed germination responses of diverse brinjal (Solanum melongena L.) genotypes under cadmium stress

Abstract

Cadmium (Cd) is one of the most toxic, highly mobile, and widely distributed heavy metal contaminants found in the environment. The present investigation was conducted to assess the genotypic variation in seed germination and early seedling growth of 30 brinjal genotypes under Cd stress at concentrations of 1.5, 3, and 6 ppm. It was observed that cadmium stress reduces the germination and early growth attributes including root length, shoot length, and seedling length of brinjal in a dose-dependent manner. Mean germination time and speed of germination were also found decrease with increased Cd level. Similarly, seedling dry weight, seedling vigour index I (SVI-I), seedling vigour index II (SVI-II), and metal tolerance index were significantly reduced under Cd stress. Pearson’s correlation analysis and principal component analysis (PCA) identified speed of germination, metal tolerance index, and SVI-I as important traits associated with Cd tolerance during the germination and early seedling stages. Hierarchical clustering based on germination and growth-related traits under the highest Cd concentration (6 ppm) identified IVBR-23, IVBL-22, IVBR-21, IVBR-20, IVBL-25, IVBR-24, IVBHR-19, and IVBHL-27 as Cd-tolerant genotypes that may be further used for breeding and development of Cd-tolerant brinjal cultivars suitable for cultivation in Cd-contaminated environments.