Gene actions of resistance to anthracnose (Colletotrichum acutatum) of six F₁ hybrid chili cultivars at the mature green fruit stage

Anthracnose is an economically important fungal disease affecting the yield and fruit quality of chili in the tropics. This study aimed to assess the anthracnose disease reaction in six hybrid chili pepper cultivars compared with their parental lines. Two male resistant lines were crossed with three commercial female parents by North Carolina mating design II. All chili genotypes were grown in the greenhouse in a randomized complete block design with three replications, 10 plants each. Five mature green fruit plant^‑1 were harvested and inoculated with C. acutatum by using the microinjection method. ANT4 had smaller lesions than ANT10. Additionally, the F₁-hybrids derived from ANT4 showed smaller disease lesions (7.47-9.82 mm) than on those derived from ANT10 (9.40-11.04 mm). However, the percentage heterosis of anthracnose disease traits in ‘Jindanil 80’ (JD) and ANT4 gave the lowest value to other parents. Hybrid JD × ANT4 showed the lowest anthracnose lesion size. However, the heterosis of cross the NM × ANT10 was the most negative at -43.68. The mode of gene action was found to be additive rather than involving dominant effects, with a narrow-sense heritability of 50.9% and broad sense heritability of 70.1%. Therefore, the resistant parent ANT4 cultivar is crucial for use as a resistant elite line for producing good F₁ hybrid tolerance to anthracnose disease.