Effect of sowing dates on different cotton varieties by Cotton Leaf Curl Virus (CLCuV) At CCRI, Sakrand

Abstract

Four cotton varieties viz; CRIS-134, CRIS-342, CRIS-486 and CRIS-494 were studied under the field conditions during cotton crop season 2011 at CCRI-Sakrand farm for the effect of sowing dates on the incidence of Cotton leaf curl virus disease (CLCuV).  The mentioned varieties were sown on 15th April, 1st May, 15th May, and 1st June and the incidence was recorded. All the varieties were found to be statistically different in their response towards CLCuV. However, among these varieties, maximum disease incidence (27.4%) was noted on CRIS-134 in 1st June sowing followed by CRIS-486 (24.2%) and CRIS-342 (13.6%). However, the minimum disease incidence (10.7%) was recorded on CRIS-494 in 1st June sowing. On an average minimum disease incidence % was recorded in all the varieties sown on 15th April and the incidence ranged from 0.8%- 4.5%. The maximum seed cotton yield was obtained from 15th April sown crop ranged from 1729- 2253 kg ha-1. The minimum seed cotton yield (726 - 1446 kg ha-1) was produced in 1st June sown varieties. From the studies, it was concluded that early sowing condensed the incidence of CLCuV as compared to late sowing crop.Population of whitefly adults were also counted on all these varieties. The maximum population of white fly was recorded in CRIS-486 (0.77/leaf) followed by CRIS-342 (0.72/leaf), CRIS-134 (0.63/leaf) and CRIS-494(0.58/leaf). Maximum temperature average ranged 39.0-470C and R.H. 42.3-66.3 were recorded in month of May 38.0-49.00C and 29.3-69.3 in the month of June, respectively. The trend of increasing temperature and R.H % also helps to raise the incidence of CLCuV.