Submitted to: Slovenian Genetics Society Meeting
Publication Type: Proceedings
Publication Acceptance Date: November 15, 2000
Publication Date: N/A
Interpretive Summary: Genetic variation is present in crop species because plants differ in their DNA constitution [i.e., they carry different forms of the same trait (e.g., small vs. large plants)]. Broad genetic variation in crop species is important because it allows plant breeders to improve plants through selection. Theoretically, the larger the genetic variation in a species the more amendable a species is for improvement. Although melon has many commercial market classes (e.g., muskmelon, honeydew), there is limited genetic variation within a market class. Therefore, it would be important to define the extent of the genetic variation in the market classes of melon, compare the genetic variation among market classes, and compare the genetic variation between commercial melon and exotic forms of African melon at the crop's center of origin. We made these comparisons using commercial melon varieties from the U.S., Europe and Japan, and exotic African varieties from northern and central-southern Africa. We used biotechnological tools to assay the genetic diversity. These tools are called molecular markers since they allow for the detection of genetic variation at the molecular (DNA) level. Genetic diversity data suggest that there are distinct differences among commercial market classes of melon and between these market types and African exotic melons. These differences are available to the melon breeder for the enhancement of genetic diversity in melon. The plant breeder can use the data from our study to strategically improve melon and thus increase the economic value of melons for the consuming public.
Technical Abstract: Cultivated melon (Cucumis melo L.) is a member of the family Cucurbitaceae. Based on differences in leaf, vine, plant and fruit characters, the C. melo subsp. melo (x = n = 12) has been further subdivided into seven horticulturally important melon groups. Two of these groups, Cantalupensis [Galia, Ogen, Charentais, U.S. fresh market, Japanese (Oriental, Earl's, and House) and Shipper (European and U.S.) types] and Inodorus [Cassaba (e.g., Piel de Sapo and Rochet market types) and Honeydew types], are of commercial interest worldwide. Molecular markers have been shown to be useful for diversity assessment among accessions in five melon groups (Cantalupensis, Conomon, Flexuosus, Inodorus, and Momordica), and elite breeding lines and cultivars. Experiments were designed to compare the genetic variation among a broad array of commerical market types (Europe, U.S., Japan) and this variation to genetic variation in the crop's center of origin (Africa). Genetic diversity data suggest that there are distinct gene pools available to the melon breeder. Since all melon groups are cross-compatible, accessions from these gene pools can be used strategically to broaden the genetic diversity of any group that has a narrow genetic base. It would be useful to identify accessions among groups that differ in phenotype. These accessions could then be random-mated to form a synthetic population that could be selected for horticultural market type. These selections could be used as donor parents in backcross introgression programs or alternatively, be subjected to recurrent selection to develop market types with a broad genetic background.