Field Screening of Cotton Genotypes for Resistance to Cotton Leaf Curl Disease (CLCuD) in Sindh

Cotton leaf curl disease (CLCuD) caused by Begomovirus(s) is economically important disease of cotton in Pakistan. Management of CLCuD using natural sources of resistance has great significance and is recognized as long term management strategy. In present study, we evaluated resistant potential of 33 cotton genotypes in agro-ecosystem of Sindh, Pakistan within thrice repeated experiments. Observations were taken at interval of 30 days after sowing on incidence and severity of CLCuD under field conditions. Then the disease index was calculated from values of initial observations on incidence and severity of the disease at each time point and finally Area Under the Disease Progress Curve (AUDPC) was calculate for the disease index and presented as semi-quantitative estimate of the disease. Results showed that there was significant difference among AUDPC values of the disease index of tested genotype (LSD=41666, P=0,0000 and LSD=70297, P= 0.0000) during 2018 and 2019, respectively. Significantly highest AUDPC value was recorded in BT.CIM-678 (664109) followed by CRIS-585 (277732) and CRIS-613 (133917) and CRIS-522 (159272) during 2018. The remaining genotypes gave significantly lower AUDPC values. Similar results were obtained during next year of experiment. Therefore, it is concluded that cultivation of BT.CIM-678, CRIS-585, CRIS-613 and CRIS-522 should be avoided in agro-ecosystem of Sindh. Further studies should be conducted for eco-friendly management of the disease.