Effect of Sowing Dates On Growth and Yield of Bt Cotton Hybrids (Gossypium Hirsutum L.)

Cotton, the king of fibres, is an industrial commodity of worldwide importance. It is also known as “White gold” because of its importance in national and international economy. In Punjab, Cotton is an important cash kharif crop and plays an important role in the agrarian economy of the state, particularly the south west districts. Productivity of cotton largely depends upon the availability of high yielding varieties and hybrids along with improved agronomic production technology e.g. optimum sowing time, planting density and proper method of planting etc. Few years back, cotton crop suffered a decline in productivity mainly due to non availability of high yielding varieties and information on planting dates respectively. Recently cultivation of Bt cotton hybrids have evoked a considerable enthusiasm in farming and scientific community for boosting cotton production. In Punjab, sowing is recommended in the month of April to mid May. But it is very difficult for the farmers to complete their sowing during this period due to delayed harvesting and threshing of wheat and cotton sowing in south-western region of Punjab continues till end May. The Bt cotton hybrids are comparatively fast growing and give better yield even under late sown conditions. However, little research work has been carried out under Punjab conditions, on suitability of Bt cotton hybrids under different sowing dates. A field experiment was conducted at Students’ Research Farm, Department of Agronomy, Punjab Agricultural University, Ludhiana, during Kharif 2009, to study the performance of Bt cotton hybrids (Gossypium hirsutum L.) under different sowing dates. Five sowing dates (April 20, April 30, May 10, May 20 and May 30) and three Bt cotton hybrids (RCH 134, RCH 314 and MRC 6304) with four replications were tested in a split plot design. The soil at experimental field was loamy sand with low organic carbon and available N while available P and K were medium. The crop sown on April 20 gave higher seed cotton yield (24.9 q ha-1) which was statistically at par with the crop sown on April 30 (23.5 q ha-1) but significantly more than the other three sowing dates. Among the three Bt cotton hybrids, RCH 134 produced significantly higher seed cotton yield (24.4 q ha-1) than the Bt cotton hybrids MRC 6304 (20.6 q ha-1) and RCH 314 (16.5 q ha-1).