ABSTRACT Waterlogging is severe abiotic stress during mung bean (Vigna radiata (L.) R. Wilczek var. radiata) production. Waterlogging impacts yield loss for the legume crop by around 40%-70%, depending on the severity and duration of the waterlogging. In total, 107 collected mung bean varieties were evaluated under managed waterlogging. The F2 population from crossing between waterlogging-tolerant and -susceptible mung bean varieties were screened under waterlogging conditions. Morphological responses to the waterlogging were recorded. Correlation and path coefficient analyses were used to identify essential traits for waterlogging tolerance and seed yield potential under water stress. Mung bean varieties in clusters 5 and 6 were high waterlogging tolerance with survival rates of 66.66% and 61.11%, respectively. Of 199 F2 lines from crossings between the Kamphaeng Sean2 and W162, 20 lines presented high waterlogging tolerance. The injury score was negatively correlated with the number of leaves at the final date of waterlogging (-0.845) and 1 wk after terminating the waterlogging (-0.885). At the final date of waterlogging condition, the number of leaves and leaf greenness stability index directly affected leaf injury at -0.5928 and -0.4385. One week after waterlogging termination, only the number of leaves affected the leaf injury at -0.8599. The number of leaves directly affected seed yield components at 0.6534 and higher than the direct effect of the other traits. Thus, the number of leaves was a suitable morphological parameter along with the injury score for selecting waterlogging tolerance. The number of leaves was a suitable parameter for selecting high seed yield potential under waterlogging conditions.

Abstract The Thailand governmental institutes play important roles in genetic improvement of sweet corn in Thailand. We assessed the genetic diversity of 268 sweet corn inbreds from three major institutes (NCSRC-KU, CNFCRC, and KKU) and three commercial hybrids using 20 SSR markers. The markers detected 224 alleles in total, with an average of 11.2 alleles per locus. Overall gene diversity was relatively high, being 0.7. Allelic richness, gene diversity, and heterozygosity in the inbreds among the three institutes were comparable. However, the inbreds from KKU possessed the greatest number of unique alleles and rare alleles, albeit they showed the highest percentage of genetic impurity. Neighbor-joining, principal coordinate, and STRUCTURE analyses showed that the inbreds were genetically different. Our findings provide insight into the breeding gene pool and population structures of the sweet corn germplasm of the public sector in Thailand, enhancing efficiency of sweet corn germplasm utilization for developing new varieties.