Stress management in rainfed Bt. cotton (Gossypium hirsutum) through foliar sprays

In India, Bt cotton is grown on 122 Lakh ha area with production of 361 lakh bales and productivity is of 501 kg lint/ha. In Maharashtra it is grown on 41 lakh ha area with productivity of 81 lakh bales and productivity is 334 kg lint/ha. Cotton is grown on large scale under rainfed condition in Marathwada region of Maharashtra State and is a preferred cash crop in Kharif season by marginal as well as large farmers. The productivity of rainfed cotton particularly in Marathwada region is uncertain due to occurrence of frequent dry spells particularly during July to September. Hence to overcome the moisture stress under such dry spells condition and to obtain the sustainability in productivity, the measures like foliar application of potassium nitrate, water spray and other micronutrients are essential for reducing the rate of evapotranspiration. The experiment was conducted during 2017 to 2019 on experimental farm of All India Coordinated Research Project on Dryland Agriculture, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani. Study resulted that application of foliar spray of KNO₃ (30 and 60 days after sowing) was significantly superior in respect of increase in cotton yield as well as Net Returns as compared to the other treatments. Similarly, application of foliar spray during dry spell was also found superior than application of foliar spray after release of dry spells. The chlorophyll content, percent RWC and NDVI were also found higher under application of foliar spray which reflected in enhancing Bt. cotton productivity.