Abstract
Phytophthora capsici causes fruit, root, and foliar blight on pepper (Capsicum annuum) in field production. Breeding for disease-resistant commercial pepper cultivars is essential to long-term management of P. capsici. In this study, the severity of Phytophthora fruit rot was evaluated in an F6 recombinant inbred line population between CM334, a landrace from Mexico, and the commercial ‘Early Jalapeño’. The two parents and 67 progeny lines were evaluated for fruit rot resistance at 3 and 5 days post inoculation (dpi) using three P. capsici isolates. Fruit shape was also evaluated for each line, and the correlation between shape and disease symptoms was investigated. Significant differences were detected among lines in lesion area measured 3 and 5 dpi, and in phenotypic traits (fruit length, width, and shape index). Of the fruit phenotypic traits measured, only fruit shape index had a significant, albeit weak (r = 0.2892, P = 0.02), correlation with lesion area when inoculated, and with only one of the three isolates of P. capsici evaluated. These results suggest that breeding for fruit rot resistance in pepper will have minimal linkage with fruit shape in the CM334 background.
