Nitrate reductase activity of black rice (oryza sativa l.) cempo ireng cultivar strain 13 and 46 as the result of plant breeding using ⁶⁰Co gamma ray on drought stress variation

Black Rice (Oryza sativa L.) has been developed as a functional foodstuff due to its higher content of anthocyanins and nutrients. Black rice productivity is relatively low, while current drought stress phenomena may decline crop productivity. The breeding effort with gamma-ray irradiation is done to improve the plant's ability to be more tolerant against drought stress and increase productivity. Some researches mentioned the use of gamma-ray radiation could initiate morphological, physiological, and biochemical changes in plants. Nitrate reductase activity can be used as a method of crop yields estimation due to its positive correlation with crop productivity. The study aims to examine the nitrate reductase activity and growth responses of the M5 generation from Cempo Ireng Black Rice strain 13 and 46 results of 60Co gamma-ray irradiation compared to black rice without radiation on drought stress variation. The research was conducted with a completely random design factorial. Drought has become a factor I with 3 levels of spacious capacity (100%, 75%, and 50%). Factor II is the black rice strain (13, 46, and no radiation). The observed variables are growth parameters, nitrate reductase activity, and chlorophyll content. The data obtained were analyzed using ANOVA continued with Duncan test at a significance level of 5%. The results showed that there was a variation of growth, chlorophyll content, and nitrate reductase activities from black rice crops irradiated by gamma rays, which is also showed a different response to drought stress. The black rice strain of 46 is the rice, which more resistant to drought stress evaluated from the growth parameters, the content of chlorophyll, and its nitrate reductase activity is higher than black rice without radiation.