SUNFLOWER HYBRIDS EVALUATION FOR CHARCOAL ROT RESISTANCE

Sunflowers (Helianthus annuus) play a vital role as a global oilseed crop, but biotic and abiotic factors threaten their yield, especially in the context of climate change. One significant challenge is charcoal rot, a disease prevalent in tropical and subtropical climates. This disease causes stem lesions, leading to wilting and premature lodging, resulting in severe yield losses, ranging from 20% to 50%. Combating this issue led to introducing disease-resistant genes as a primary strategy. This study investigates the outcomes of incorporating charcoal-resistant lines into a breeding program. Four resistant inbred lines-'B-208', 'B-124', 'B-224', and 'B-112'-reached crossing with male fertility restorer lines, creating 16 half-sib cross combinations. These crosses showed varied levels of resistance to charcoal rot. Notably, the combinations 'C.112' x 'RSIN.82' and 'C.208' x 'RH.344' exhibited minor infestations and displayed negative heterosis, indicating a tendency toward complete to overdominance in resistance traits. The estimates of heterosis were modest, with a significant dominance variance relative to additive variance for disease resistance. Lines 'B-112', 'B-208', and 'RSIN.82' demonstrated strong general combining ability effects, suggesting their potential usefulness in breeding programs.