Physio-Agronomic Response of Mungbean [(Vigna radiata (L.) Wilczek] Genotypes to Waterlogging

Abstract

The extent of damage from waterlogging may vary with its timing and the type of genotypeexposed. Effects of week-long waterlogging during three phenological phases onphysiological, growth and yield parameters of two mungbean genotypes was examined in agreenhouse experiment. Aaverage losses in photosynthesis rate from waterloggingamounted to 42, 87 and 73% for the vegetative, flowering and seed filling phases,respectively. The corresponding drops for transpiration rate were 36, 84 and 64%. Effects onphotosynthesis and transpiration rates closely followed impacts of waterlogging on stomatalconductance. Genotype MH-97-6 had shown consistently greater rates for the physiologicalparameters during the terminal phase. Shoot dry matter decreased by 68% due towaterlogging at flowering while falls of 39 and 45% occurred under early and terminalwaterlogging, respectively. Root growth was resilient to early waterlogging while it suffered59 and 44% losses due to flowering and terminal waterlogging, respectively. Earlywaterlogging increased root-shoot ratio by 104% at the end of the stress period. The highestseed yield drop of 85% appeared due to waterlogging at flowering. The remaining twophases were less affected with falls amounting to half of that observed under midwaterlogging. In spite of its better root system and greater dry matter allocation to the root,genotype Sunaina has not shown superior tolerance to waterlogging. The significant yieldpenalty from early waterlogging indicated the crop's sensitivity to short term waterlogging.It would be worthwhile to screen more genotypes against waterlogging with incorporation ofadditional factors such as nutrient management and soil type.