|HAUSBECK, MARY - Michigan State University|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2020
Publication Date: 11/17/2020
Citation: Naegele, R.P., Hausbeck, M. 2020. Phytophthora root rot resistance and its correlation with fruit rot resistance in Capsicum annuum. HortScience. 55(12):1931-1937. https://doi.org/10.21273/HORTSCI15362-20.
Interpretive Summary: The water mold Phythopthora capsici causes disease on a number of important vegetable crops. Disease management relies on chemical and cultural controls, but losses still occur under favorable conditions. Host resistance is one tool needed to help manage the pathogen. Resistant peppers have been identified previously, but few have been evaluated to multiple isolates individually, and no information is available about the correlation between fruit and root rot resistance. This study evaluated a diverse set of pepper plants for resistance to P. capsici, and compared these results with fruit rot resistance data.
Technical Abstract: Phytophthora capsici causes root and fruit rot and foliar blight of pepper. Multiple sources of resistance to Phytophthora root rot have previously been identified, but most display only partial resistance. One source, CM334, has broad spectrum resistance to multiple pathogen isolates, but has not been confirmed. This study evaluated previously identified pepper lines for resistance to two P. capsici isolates and compared root rot resistance to fruit rot resistance and genetic structure. CM334 was confirmed as a broad spectrum resistance genotype, while all other sources of resistance evaluated were susceptible to infection by one or both isolates evaluated. Though not completely resistant, PI 566811 displayed moderate resistance to fruit and root rot to both P. capsici isolates. Fruit rot resistance had a significant, but small to moderate positive correlation with root rot resistance depending on the isolate and length of exposure. Pepper accessions with resistance to Phytophthora root and fruit rot belonging to different genetic sub populations were identified and could serve as candidates for partial-resistance loci to incorporate into pepper breeding programs.