Isoflavone characters of three soybean varieties under drought stress with application of nitrogen sources

Abstract

Human interest in soybean greathyincreasedin recent years due to the positive effects of secondary metabolites in soybean such as isoflavones for human health. Isoflavones are phytoestrogens worked as the antioxidant and chemopreventive agents for estrogenic compounds that can inhibit cell proliferation. Isoflvones also serves to prevent heart damage, osteoporosis and manaupose syndrome, prevent prostate, colon cancer and breast cancer. Daidzein, genistein and glycitein are the major isoflavones in soybean. A research about isoflavone characters of three soybean varieties under drought stress with application of Nitrogen sources was conducted in green house, Faculty of Agriculture,University of Sumatera Utara. The aim of the research was to study the effect of Nitrogen sources under drought stress on isoflavone characters of three soybean varieties. The experiment used a Factorial Randomized Block Design with three factors and three replications. The first factor was soybean varieties consisted of Anjsmoro, Wilis and Sinabung. The second factor was Nitrogen sources consisted of without N fertilizer application; Urea 50 kg/ha, Bradyrhizobium sp., cow manure 10 t/ha, rice straw compost 10 t/ha. The third factor was soil water content condition namely 50%, 60%, 70 and 80% of field capacity. The parameters observed were isoflavone characters consisted of genistein, daidzein, glycitein and isoflavone total. The result showed that Anjasmoro variety had the genistein, daidzein, glycitein and isoflavone total contents of soybean higher than Wilis and Sinabung. The Application of Nitrogen sources increased the genistein, daidzein, glycitein and isoflavone total contents of soybean compared without application of Nitrogen sources. There is a distinct pattern in the increase in the isoflavone total content in Anjasmoro, Wilis and Sinabung with increasing the drought stress, At Anjasmoro variety, increasing drought stress caused the lower of isoflavone total content, while the varieties Sinabung and Wilis are opposite pattern.