Genomic-assisted breeding for disease resistance in cucurbit cultivars
Cucurbit growers and processors consistently identify fungal/oomycete pathogens and insect-transmitted viral diseases as major production constraints causing severe reductions in yield, loss of fruit quality, and increased labor and expense for control. Disease-resistant cultivars are the most cost-effective and environmentally desirable solution to these problems. Since acceptance and value of new cultivars depends on a combination of yield and ease of production for the producer, and price and desirability for the consumer, breeding programs must combine multiple disease resistances without sacrificing yield or quality.
Cucurbit breeders must find sources of resistance, identify loci conferring resistance, incorporate new resistances into elite cultivars, and combine resistances to multiple diseases. Sequencing and bioinformatics tools can facilitate more rapid and accurate identification of relevant genomic regions, and development of molecular markers for marker assisted selection (MAS). MAS, which allows for direct DNA screening in early generations or growth stages, is of particular value for disease resistance as screening for one resistance may preclude screening for another, and disease response can be strongly influenced by environment.
CucCAP breeding objectives are to map resistance loci for key cucurbit diseases; develop and verify molecular markers for efficient trait selection and gene pyramiding, and to introgress resistances into advanced breeding lines. For each of the priority crop-disease combinations, as well as several additional combinations, screening methods have been developed and sources of resistance have been identified. The current status of breeding for the priority cucurbit diseases varies with crop/disease combination.
Cucurbit Breeding Links
Cornell’s list of resistant varieties
Information about vegetable varieties available in recent seed catalogs including seed companies marketing them, whether organic seed is available, variety resistance to disorders,
and a link to download disease-resistant variety spreadsheets.
Cucurbit Genetics Cooperative
The Cucurbit Genetics Cooperative website is an organizational vehicle for scientists to share the results of their research and development efforts in the genetics and breeding of species of the Cucurbitaceae crop family. The cooperative emphasizes the free exchange of information and germplasm among members, both public and private.
Cucurbit Genomics Database (CuGenDB)
The Cucurbit Genomics Database (CuGenDB) serves as a central portal of Phenotypic data for cucurbit comparative and functional genomics.
Melon Powdery Mildew Database at UC Riverside
This website provides instructions for inoculum production procedures, collection of conidia for cryopreservation, and maintenance & sub-culturing strains of melon powdery mildew on squash leaves.
NC State Cucurbit Breeding
Cucumber Breeding and Watermelon breeding research in the cucurbit breeding program at NC State focuses on collection and evaluation of germplasm, qualitative genetics of important traits, quantitative genetics, selection methods, yield improvement, induced mutation, and resistance to cold, insects, and disease.