Downy mildew (DM) is an important disease of cucumber and other cucurbits. Many quantitative trait loci (QTL) have been identified from different resistant resources but very few have been fine mapped or cloned. CucCAP researchers in USDA-ARS and the University of Wisconsin Madison reported identification and functional characterization of the candidate gene for the major-effect QTL, dm5.3, for DM resistance from the plant introduction line PI 197088. This gene, which can enhance plant disease signaling, is currently being used to breed for disease resistance in cucumber.
Featured Articles
The CucCAP website features recently published articles from the four crop teams, (Cucumber, Melon, Squash, and Watermelon) and the Bioinformatics, Breeding, & Genomics group. Integtated crop and disease management activities, articles and reports are also featured.
CucCAP scientists use genomic approaches to facilitate breeding for PRSV-W resistance in squash
Papaya ringspot virus-W (PRSV-W) causes severe yield losses in squash production. The Meru laboratory at the University of Florida identified a single QTL for resistance on Chromosome 09 of the C. moschata genome. Subsequent testing identified two SNP markers as potential targets for marker-assisted selection. The findings of this study will facilitate breeding for resistance against PRSV-W in commercial squash cultivars.
CucCAP scientist examines economic impacts of reduced fungicide efficacy against downy mildew
Resistance to fungicides is a concern with cucumber downy mildew, Pseudoperonospora cubensis clade 2. These fungicides still suppressed downy mildew well enough that yields of marketable-sized fruit of a susceptible slicing cucumber were much better than not spraying.
CucCAP researchers evaluate disease control options for downy mildew on pickling cucumber
Cucurbit downy mildew (CDM), is an economically significant disease of cucurbitaceous crops in the Eastern United States (US). Cucumbers are particularly susceptible and as a result, disease management of this pathogen relies heavily on fungicide use.
CucCAP scientists examine mechanisms of watermelon resistance to viral infection
Watermelon production in the U.S. and around the world faces serious threats by viral diseases, including aphid-transmitted potyviruses: papaya ringspot virus (PRSV) and zucchini yellow mosaic virus (ZYMV). In a recent study, a CucCAP team examined expression of anti-microbial/anti-viral, ribosome-inactivating proteins (RIPs) in watermelons in response to inoculation with PRSV. The PRSV-resistant citron watermelon (Citrullus amarus) exhibited high RIP expression, versus low expression in plants of the susceptible, cultivated “Charleston Gray” watermelon. This finding may offer additional genetic and genomic resources for improving potyvirus-resistance in watermelon cultivars.
CucCAP researchers review producers’ willingness to pay for new varieties
Stated preference surveys are a relatively new approach to measuring specialty crop producers’ valuation of breeding traits.
CucCAP scientists map QTL for resistance to powdery mildew in melon
Powdery mildew is one of the most important diseases of melon. CucCAP researchers used a densely genotyped melon population to identify QTL associated with resistance in multiple plant tissues.
CucCAP researchers identify QTL for Phytophthora resistance in squash
Scientists at the University of Florida led by Geoffrey Meru characterized resistance to Phytophthora crown rot in PI 181761 and identified a major QTL on chromsome 13. Several SNP markers were designed to target this QTL for marker-assisted selection.
