Cheap and rigorous method of screening soybean cultivars for drought tolerance

Environmental stresses cost plants in a variety of ways, starting from altered gene expression through modified cellular metabolism to changes in growth rates and crop yields. One of the major environmental stresses is drought, which drastically affect the crop productivity. Current study screened 69 soybean cultivars on the basis of their drought tolerance ability by devising an easy, rapid, reliable, and inexpensive screening technique. Growth, biomass and physiological parameters of the selected cultivars were measured after growing them for 42 days in hydroponics. Inter-cultivar variations in the selected parameters of the control and stressed plants were analyzed to group the soybean cultivars in tolerant (T), susceptible (S), and highly susceptible (HS) cultivars. In fact, polyethylene glycol as drought stress has significantly affected the roots and shoots length, roots and shoots weight, nodule weight, photosynthesis and chlorophyll contents in the majority of the soy cultivars. Moreover, few cultivars have retained the above mentioned growth parameters under the drought stress conditions, but changes in transpiration rate (TR) was insignificant in Seoul only. Based upon overall performance, 13 cultivars were found tolerant, 13 cultivars were susceptible and 43 cultivars were highly susceptible to drought stress among the 69 tested cultivars of soybean.