Occurrence of cotton leaf curl disease on American cotton under changing climate context in Punjab

摘要

Cotton is one of the most important cash crops in India grown in 12.7 m ha area with lint productivity of 523 kg/ ha. In Punjab, cotton is being cultivated in about 0.45 m hectares area with a total production of 11.5 lakh bales and productivity of 529 kg/ ha (Anonymous, 2014). Cotton leaf curl disease (CLCuD) is the major factor for the low productivity especially in north India. In Punjab, cotton leaf curl disease was first reported from Ferozepur district bordering Pakistan in 1994 and has causedsubstantial reduction in yield for the last ten years. Depending upon the stage of crop and intensity of disease, the loss in seed cotton yield varied from 10.5 to 92.2 per cent in susceptible varieties of upland cotton (Singh etal, 1995; Monga et. ah, 1998). The malady caused 68.1-79.2 per cent reduction of seed cotton yield in India (Monga et. al, 1999). Further Singh (2006) found there was 50.4% reduction in number of bolls and 42.9% reduction in boll weight of plants due to CLCuD infection in variety F 846. This malady reduced the fibre length by 5.2%, strength by 5.4% , elongation by 10.0%, uniformity by 2.2% and miconarie value by 4.1 % in diseased plants over the grade 0 ( healthy) plants in variety F 846. Most of the cotton hybrids (including undescripts) grown in Punjab are susceptible to this disease. Considering the importance of the disease, the present investigations were undertaken from Kharif 2005 to Kharif '2012, with the objective to study the time of its first appearance, pattern ofoccurrence and its further spread on various varieties/hybrids in the main cotton growing belts of the Punjab state.