DefinePK

Abstract

Cotton leaf curl disease (CLCuD) is one of the most destructive diseases significantly constraining the growth and output of cotton. Despite cultivation of resistant genotype against CLCuD is emphasized and is easily adoptable strategy for managing the disease in cotton crop throughout the world. But due to unavailability of resistant sources and resistant breaking potential of the virus there is need to consider alternate management approaches for CLCuD management. Therefore, the aim of this study was to determine the effects of various sowing times of different cotton genotypes on CLCuD intensity. In a two-year field study four cotton genotypes such as Bt. CRIS-671, Bt.CRIS-673, CRIS-585 and CRIS-613 were evaluated at different planting dated i-e, 1st April, 15th April 1st May and 15th May in split plot randomized complete block design. CLCuD incidence, severity and vector population were assessed at 30-day intervals after sowing (DAS). Disease index and Area Under the Disease Progress Curve (AUDPC) were computed and statistically analyzed using LSD at α = 0.05. Results indicated a significant difference among the various sowing dates during both year of the study. Infection due to CLCuD also varied significantly among genotypes. There was less disease incidence on 1st April planted cotton as compared to late sown cotton (1st & 15th May). Maximum CLCuD incidence 100% was recorded in late planting at 120 days after sowing in CRIS-613 and Bt. CRIS-713 both the year of study. Bt. CRIS-671 consistently exhibited lower disease severity and AUDPC values compared to other genotypes. The least severity was observed when Bt. CRIS-671 was sown on April 15th (S2). Significantly lower AUDPC values 360000 and 367550 were determined in Bt. CRIS-671 at 15th April (S2) during 2019 and 2020, respectively. In contrast, late sowing dates (May 15th, S4) resulted in higher disease severity and AUDPC values, especially in CRIS-613 and Bt. CRIS-673. Statistical analysis confirmed significant differences in disease progression across sowing dates and genotypes, highlighting the importance of optimal sowing dates for managing CLCuD. Whitefly populations were also lowest in Bt. CRIS-671 and Bt. CRIS-673 when sown early (April 1st and April 15th). From the present study it is concluded that early planting on 1st April resulted with minimum disease and is suggested for including in the disease management strategy.