MORPHO-PHYSIOLOGICAL ASPECTS OF MUNGBEAN (VIGNA RADIATA L.) IN RESPONSE TO WATER STRESS SHIHAB UDDIN 1 , SHAHNAJ PARVIN 2 & M. A. AWAL 3 1,2 Department of Agronomy, Bangladesh Agricultural University, Mymensigh, Bangladesh 3 Department of Crop Botany, Bangladesh Agricultural University, Mymensigh, Bangladesh ABSTRACT Water limitation may prove to be a critical constraint to crop growth. Mungbean is most susceptible in that respects neither tolerate deficiency nor the excess moisture. Therefore, the present experiment was conducted to assess water stress consequence on the morpho-physiological attributes of mungbean (Vigna radiata L.) cv. BINA mung 5 in Agronomy Field Laboratory, Bangladesh Agricultural University, Bangladesh during October 2011 to February 2012. The trial comprised seven treatments of irrigation in different growth stages. Results revealed that moisture stress hampered the mungbean growth significantly and reduced the growth rate. All morphological and physiological attributes showed the best performance under T 7 where three irrigations applied and the lowest performance showed under T 1 (no irrigation) due to moisture scarcity. Moisture scarcity resulted higher flower and pod abscission (53%) which enhanced early maturity of mungbean. The lowest values of assimilate partitioning were found from no irrigation might be the highest level of moisture stress compare to other treatments which changed the distribution of photosynthetic pattern. Flowering to maturity found the most critical stage where water scarcity reduced pod dry matter. Maintain adequate soil moisture during the period of flowering to pod maturity encouraged pod filling and ensure higher yield of mungbean. KEYWORDS: Water Stress, Mungbean, Irrigation, Growth Rate, Assimilate Partitioning, Moisture Sensitive Phase INTRODUCTION Pulses play a vital role to meet the protein demand of human diet. Pulses are considered as the poor people’s meat as it is the cheapest source of protein. In Bangladesh, per capita daily consumption of pulses is only 13.29 g day -1 (BBS, 2011). While the World Health Organization (WHO) suggests consuming 45 g day -1 per capita pulses in Bangladesh . To maintain the supply of this level, the Government of Bangladesh has to spend a huge amount of foreign currency each year. Annual import of pulses in Bangladesh is approximately 108000 m tons (BBS, 2011). Mungbean is highly adapted to the agro-climatic condition of Bangladesh. Though the agro-ecological condition of Bangladesh is favourable for mungbean cultivation, its area under cultivation and total production are low in this country. Soil moisture stress is an environmental condition which affects physiological processes of the plant. Mungbean is cultivated during dry season (October to April) in Bangladesh and during this period no rainfall causes depletion of soil moisture level resulting drought effect that impair the physiological aspect of dry matter accumulation. A common feature of the climate in Bangladesh is the uncertainty of rainfall, therefore probable significant soil water deficit leading to plant water deficit at various stages of growth. Drought is a widespread climatic event which frequently limits growth of mungbean. Mungbean response to water stress resulting in lower yields (Miah and Carangal, 2001). The decrease in crop biomass production is frequently observed International Journal of Agricultural Science and Research (IJASR) ISSN 2250-0057 Vol. 3, Issue 2, Jun 2013, 137-148 ©TJPRC Pvt. Ltd.