Productivity potential, quality and economic viability of hybrid Bt cotton (Gossypium hirsutum)-based intercropping systems under irrigated conditions

A field experiment was conducted during the rainy (kharif) season of 2010 and 2011 at Ludhiana, Punjab, to study the effect of different intercrops and row ratio on the growth, yield and quality of hybrid Bt cotton (Gossypium hirsutum L.). The number of opened bolls and seed-cotton yield obtained by intercropping Bt cotton with fodder maize [Zea mays L., Saccharata), fodder cowpea [Vigna unguiculata (L.) Walp.], summer mungbean [Vigna radiata (L.) wilczek] and long melon [Cucumis melo L. var. utilissiumus Duth & Full.] was statistically at par with sole Bt cotton. However, Bt cotton intercropped with fodder pearlmillet or bajra [Pennisetum glaucum (L.) R. Br. emend. Stuntz] recorded significantly lower number of opened bolls and seed-cotton yield. The Bt cotton, when intercropped with fodder maize in a 1:1 row ratio recorded 43.4% increase in seed-cotton equivalent yield as compared to sole Bt cotton. The seed-cotton equivalent yield obtained from all other intercropping systems except Bt cotton intercropped with fodder pearlmillet in 1:1 and 1:2 row ratios and intercropping of Bt cotton with long melon in 1:2 row ratio recorded significantly higher seed-cotton equivalent yield than sole Bt cotton. Bt cotton when intercropped with long melon showed the highest values of land-equivalent ratio (LER), (1.80) in 1:2 row ratio and area time equivalent ratio (ATER), (1.29) in 1:1 row ratio. The cotton quality parameters like ginning outturn, seed index, lint index, oil percentage and micronaire value were not significantly influenced by intercropping in Bt cotton. However, the fibre strength was significantly reduced by intercropping Bt cotton with fodder maize in 1:1 and 1:2 row ratios, fodder cowpea in 1:1 row ratio and long melon in 1:1 row ratio. The maximum net returns of 54,060/ha were obtained when Bt cotton was intercropped with fodder maize 1:1 rows, being 68.6% higher than sole Bt cotton. It was followed by intercropping Bt cotton with fodder maize in1:2 row ratio, which recorded 53.4% higher returns than sole Bt cotton. Among the different intercropping systems, the maximum benefit: cost ratio (2.47) was also obtained by intercropping Bt cotton with fodder maize in 1:1 row ratio.