Effect of different foliar sprays on biomass and yield of mungbean (Vigna radiata Wilczek) grown inderwater deficit

Foliar spraying is a known technique in fertilizer application, it involves direct entry of the nutrients through the stomatal opening of the leaves. Recent studies suggest that its application also helps in adaptation of plants on certain environmental stresses. In this study, the different effects of foliar sprays on drought tolerance of mungbean (Vigna radiata Wilczek) was conducted at the Institute of Plant Breeding. CAFS, UPLB [College of Agriculture and Food Science, University of the Philippines Los Baños] under screenhouse and field conditions. Foliar sprays included abscisic acid (ABA), gibberellic acid (GA sub 3), glutathione (GSH), potassium nitrate (KNO sub 3), carrageenan (Car) and salicylic acid (SA). Applications were made using suggested concentrations from different drought related studies: ABA and GA sub 3(1mum), SA, GSH and KNO sub 3 (50mum) 1:10 v/v carrageenan: water; and were applied via spraying 3 days after the initiation of drought, 30 days after planting. The greenhouse experiment was laid out in randomized complete block design with split-plot (mainplot,water regime; subplot, variety and sub-sub-plot, foliar spray). Under greenhouse conditions, significant differences in root dry matter were observed across treatments. It was observed that 'drought' plants treated with SA, GA sub 3 and KNO sub 3 had significantly higher root dry matter, however well-watered plants still showed the highest dry matter content. The field experiment was laid out in randomized complete block using 4 mungbean varieties (Pagasa 3, 7, 5 and 19) combined with water regime and foliar spray as one treatment. Under field conditions there was an increase in dry matter of 13-30% in 'drought' plants sprayed with GA sub 3, KNO sub 3 GSH and ABA. These same plants also had increased in seed yields under drought conditions. Results suggest that these foliar sprays have the potential to increase tolerance of mungbean plants to drought stress.