Effect of nutrient management on FUE, red leaf, fibre properties of Bt hybrid cotton (Gossypium hirsutum)

A field experiment was conducted during 2008, 2009 to study the effect of nutrient management on fertilizer use efficiency (FUE), red leaves and fibre quality in multiple pickings of Bt hybrid cotton (Gossypium hirsutum L.) at Central Institute for Cotton Research, Nagpur (21° 09′ N, 79° 09′ E). Senescence was faster in Bt hybrid cotton in mid-October, 2008 with deficient rainfall in shallow soils. Soil application of MgSO₄ @ 25 kg/ha/3year in shallow soils significantly reduced the formation of red leaves in October. Cell sap sucking jassids and thrips on Bt hybrid cotton (Bunny) leaves caused N deficiency and accumulation of anthocyanin in August month. Higher FUE was observed in non Bt hybrid cotton compared to Bt hybrid cotton. Fertilizer response, FUE and profitability was significantly improved by application of 150% RDF or ZnSO₄ @ 25 kg/ha/3year + MgSO₄ @ 25 kg/ha/3year + borax @10 kg/ha/3year + sulphur @ 20 kg/ha/2 year together. Bt hybrid cotton was significantly not profitable with lesser returns and lower yields than non Bt isogenic line of NCS 145 under adverse weather conditions and resurgence of sucking pests. Bundle strength tenacity (g/tex) at 3.2 mm guage and fineness were not significantly affected across pickings, both were 15%-18% shortage of spinning norms.