Genetic effects on resistance to Phytophthora capsici in chile of agua

Abstract

Genotypes of chile de agua (Capsicum annuum L.) were evaluated under greenhouse conditions to identify resistance to Phytophthora capsici. The experiment was arranged as a randomized complete block design (RCBD) with two replications and two treatments (inoculated and non-inoculated). Twenty-one single-cross F1 hybrids were generated using Griffing’s diallel method II (parents and F1s). With the seven parents and 21 F1 crosses, a total of 28 genotypes were assessed. Disease severity was rated, and the Disease Index (DI) and the Area Under the Disease Progress Curve (AUDPC) were computed. Analysis of variance (ANOVA) revealed significant differences among genotypes. Crosses 1x5, 4x6, and 6x7 exhibited the lowest DI and AUDPC values. Diallel analysis indicated significant general combining ability (GCA) and specific combining ability (SCA) effects. Parents 3, 5, and 8, together with the crosses, are promising sources for breeding programs targeting resistance to P. capsici. El estudio se realizó en Saltillo, Coahuila, México, en 2024.