Growth and Yield Response of Mungbean (Vigna radiata L. Wilczek) Genotypes to Wet Puddling, Flooding and Saturated Soil Culture

Abstract

Anoxia and hypoxia, caused by excessive rainfall and inadequate drainage are the most common environmental stresses in upland crops after wetland rice in many regions of Asia. Such stresses and/or puddling of soil in rice culture often reduce the growth and yield of post-rice upland crops. This study examined the growth and yield responses of three mungbean genotypes viz. VC3950-88, VC6173A and BARI Mung-5 to three different environmental stresses viz. wet puddling, soil flooding and saturated soil culture. Wet puddling significantly reduced the field emergence and vigor index of seedlings. Height of plants was also adversely affected due to the stresses, although recovery was comparatively better in flooded situation. Irrespective of growing conditions, leaf chlorophyll index reduced significantly and recovered almost completely. The extraordinary responses of plants to all the stresses were the damaging of roots and/or impairing of root and shoot growth. The subsequent recovery of root and shoot growth significantly varied depending on the types of stresses. The development of numerous adventitious roots and the production of greater amount of root nodules were the most important recovery mechanisms of plants to withstand flooding situation and saturated soil culture, respectively. As a result, seed production was less affected under these two conditions. In contrast, wet puddling situation performed the worst, showing depressed plant growth throughout the growing period and thus seed production was affected the most. Among the genotypes, VC6173A was best adapted under the three stresses, giving the highest seed yield by producing higher amount of pods, increased seed size and longer pod.