Field Screening for Leaf Curl Disease Resistance in Sunflower (Helianthus annuus L.) Genotypes

In India, sunflower cultivation is increasingly constrained by leaf curl disease, primarily caused by begomoviruses transmitted by whiteflies. This study aimed to evaluate the resistance of 48 sunflower genotypes to leaf curl disease during the rabi season of 2024–25 at the Regional Agricultural Research Station, Nandyal. Disease severity was assessed at four growth stages using the Percent Disease Incidence (PDI). Significant genotypic variation was observed across all stages. Statistical analysis, including ANOVA and heritability estimates, indicated that environmental influence was minimal, with high heritability and genetic advance suggesting additive gene action in resistance expression. Disease progression parameters such as apparent infection rate and area under the disease progress curve supported these findings. The genotype NDLA-2 × NDI-51 showed consistently low disease incidence. These results highlight potential genotypes for use in breeding programs aimed at improving resistance to leaf curl disease in sunflower, contributing to the development of more resilient hybrids suited for Indian agro-climatic conditions.