Effects of refuge crops and sowing dates on the growth and yield performance of Bollgard II variety of cotton (Gossypium hirsutum L.) in Allahabad condition

Abstract

Extensive use of pesticides and insecticides to control various kinds of pests and bollworms in Bt (Bacillus thuringiensis) cotton to create ecological imbalance in the environment. For managing that natural refuge crops helps to delay resistance in Bt cotton. An experiment was conducted to estimate the effect of refuge crop and sowing dates on growth and yield performance of Bollgard II variety of Bt cotton in two different Departmental Fields at Sam Higginbottom University of Agriculture, Technology and Sciences, Allahabad (Uttar Pradesh) during 2016. When alternatively sown 50% Bt with 50% refuge nBt cotton, significantly early planting cotton of first field gave more number of monopodial branches plant-1(2.55) sympodial branches plant-1 (17.00) than the refuge nBt cotton whereas plant height (cm) was found maximum in 50% refuge nBt cotton (139.33) and yield attributes was found maximum in 50% Bt than 50% nBt. In case of planting date, early planting cotton during mid march gave significantly more plant height (130.44 cm), monopodial branches plant-1 (2.50), sympodial (fruiting) branches plant-1 (26.00), bolls plant-1 (27.55), Average weight of bolls plant-1 (3.38), No. of seeds plant-1 (511.55) and lint weight (g) plant-1 (19.07) than late sowing during mid May under different cultivars.