Deciphering of Genotype × Environment Interaction to Identify Stable Heat-Tolerant Mung Bean Genotypes by GGE Biplot Analysis

Under the climate change scenario, high-temperature stress declines crop yields. The present study was designed with the objectives to identify the stable heat-tolerant genotypes for grain yield under normal and heat stress conditions at three locations. The 80 mung bean genotypes and 3 check varieties were sown in three agro-ecological zones of Pakistan, namely, Chakwal, Piplan, and Bhakkar. The experiments were planted in two sowing dates, i.e., the normal sowing and late sowing by using an augmented randomized block design with 6 blocks at each location. The plot size for each genotype was 2.4 m2 at all the locations. All cultural and agronomic practices were carried out as per recommendations. Ten randomly selected plants were used to record the yield-related traits. An infrared gas analyzer (IRGA) was used to measure physiological traits like photosynthesis rate and stomatal conductance. To study the nature of relationship among traits, Pearson correlation analysis was done using SPSS software (v. 16.0). The GGE biplots were constructed to graphically represent the genotype and GE interaction of multi-environment data using the software plant breeding tools. Three views of the GGE biplot were generated to display the comparative performance, rank, and stability of each genotype in the tested environments. Correlation and principal component analysis (PCA) revealed a positive interaction of grain yield with pods plant−1, seed pod−1, 100 grain weight, and harvest index, while days to flowering and maturity had a negative association under normal and heat-stressed conditions. The GGE biplot analysis efficiently explained 85.1% of the total variation and demonstrated that among 8 vertex genotypes of polygon biplot, the G14 and G38 were heat tolerant as these genotypes outclassed others in all the heat-stressed environments. In contrast, the genotypes G51 and G74 produced maximum yield under normal conditions (E3 and E5). Among all the genotypes, genetic diversity was observed for grain yield and other morpho-physiological traits. Significant G × E interaction was observed. The genotypes G14, G38, and G51 were identified as stable and heat tolerant in most of the environments. These findings will be helpful for development of heat-tolerant mung bean breeding material in the future.