Watermelon is affected several pathogens and pests that are frequently controlled by SDHI compounds. Scientists from North Carolina State University compared the sensitivity of the different pathogens to various SDHIs.
Phytophthora fruit rot is a major disease impacting pickling cucumber production for which there are no resistant varieties. Genomic approaches were performed on the cucumber core collection leading to identification and verification of several quantitative trait loci associated with resistance. The results from this work can be applied to future disease resistance studies and to assist marker-assisted selection in breeding programs.
Scientists at the USDA, ARS, U.S. Vegetable Laboratory in Charleston, SC evaluated the USDA, ARS citron watermelon germplasm collection for flowering time and fruit yield traits under field conditions over two years. They used a “genome-wide association study (GWAS)” to detect genomic regions and molecular (DNA) markers associated with flowering time and fruit yield traits. The new molecular markers will be useful in improving watermelon varieties for early flowering and maturity and yield performance via marker-assisted breeding.
Cucurbit downy mildew is a major threat for pickling cucumber production requiring frequent fungicide applications.
A super-pangenome was constructed to represent the entire watermelon gene repertoire, uncovering several disease resistance genes that are present in wild watermelons while completely lost in watermelon cultivars.
The gummy stem blight fungus, Stagonosporopsis citrulli, is now resistant to fungicides in four chemical classes. The newest resistance is to fungicides in FRAC Code 3.
Citrullus amarus was screened for resistance to Pseudomonas leaf spot. Genetic markers associated with resistance to P. syringae and other diseases were identified. The results will facilitate breeding for resistance to PLS in watermelon.
The compact (cp) phenotype in cucumber is an important plant architecture-related trait with potential for breeding short-vining cucumber plants for high density planting and mechanized harvest.