Discrimination of Mung Bean (Vigna Radiata L.) Genotypes Exposed to PEG-Induced Water Deficit Reveals the Selection Criteria for Improved Breeding from Germination to Seedling Development

Mung bean is a valuable pulse crop that faces a considerable water shortage during its growth period (March-May). Hence, the study was formulated to determine the variability and diversity of 33 mung bean genotypes from three institutes in Bangladesh. The mung bean genotypes were screened based on the genetic variation in germination and seedling growth traits induced by polyethylene glycol (PEG 6000) stress (-0.07,-0.1,-0.2, and-0.4 MPa). The results showed that the phenotypic coefficient of variation was significantly higher than the genotypic coefficient of variation for all the studied traits. The broad-sense heritability showed a wide range of moderate to high (24.26-99.19%) variability. Using D2 analysis, the tested genotypes were grouped into five clusters based on the genetic variability, where cluster III was the largest one consisting of 11 genotypes. The PCA analysis revealed the traits that contributed to 98.19% of the total variation and these included germination (GN), Coefficient of germination (CEG), Mean germination time (MGT), Speed of germination (SG), and Vigor Index (VI). The greater inter-cluster distance was found in Cluster III (16.50) with the highest intra-cluster distance observed in Cluster II (0.12). The genotypes BARI Mung-2, BARI Mung-8, BMX-01015, BMX-08009-7, and BMX-08010-2 under Cluster V gave a remarkable performance with the highest mean value in almost all observed traits. For this fact, parent selection under this cluster would provide higher heterosis if hybridized. Overall, the present study revealed the selection criteria useful for the development of drought-tolerant mung bean genotypes for improved breeding.