|WEHNER, TODD - North Carolina State University|
Submitted to: SpringerPlus
Publication Type: Book / Chapter
Publication Acceptance Date: 10/15/2016
Publication Date: 12/22/2016
Citation: Wehner, T.C., Naegele, R.P. 2016. Genetics and genomics of the Cucurbitaceae: genetic resources of cucumber. SpringerPlus. Available: https://link.springer.com/chapter/10.1007/7397_2016_15.
Interpretive Summary: The Cucurbitaceae or vine crop family includes many important vegetables collectively referred to as cucurbits. Cucurbit plants are trailing or vining, tendril-bearing, frost-sensitive annuals. The fruit are variously shaped and multiseeded. Cucumber, melon, and watermelon are major cucurbit species originally from the Old World (cucumber from India; melon and watermelon from Africa) and currently grown worldwide. Cucumber, the most widely grown cucurbit, is thought to have originated in India, where it is found wild and cultivated in many diverse forms. Secondary centers of diversity for cucumber exist in China and the Near East. Cucumber was likely domesticated in Asia, and introduced into Europe, where the first cultivars were selected in the 1700s. Cucumbers were brought to the Americas by Christopher Columbus, and Native Americans were growing cucumbers from Florida to Canada by the early sixteenth century. During this period, cucumber has lost much of its genetic and morphological variation. Related species are Cucumis hystrix from China, and the African Cucumis species, such as melon (Cucumis melo), gherkin (Cucumis anguria), and their wild relatives. Wild relatives can harbour useful traits, such as disease resistance, which are useful for breeding improved cultivars. In cucumbers, more than 150 traits controlled by a single gene have been described, and individuals with these traits have been identified as sources for breeding.
Technical Abstract: The Cucurbitaceae or vine crop family includes many important vegetables collectively referred to as cucurbits. Within Cucurbitacae, the genus Cucumis includes cultivated species C. sativus (cucumber) and C. melo (melon), as well as wild species including C. hystrix, C. callosus, and C. sativus var. hardwickii. More than 50 species have been identified in Cucumis with high levels of phenotypic and genetic diversity found in centers of diversity in Africa, Asia, and India. During domestication, cucumber and melon underwent severe bottlenecks, which resulted in low genetic diversity despite high phenotypic diversity. Primary and secondary centers of diversity can serve as useful sources of variation, and have been widely used to incorporate traits such as disease resistance into cultivated materials. Since its domestication, approximately 3000 years ago, cucumber has undergone significant morphological changes from its small-fruited, black spined, seedy progenitor. More than 150 single gene traits have been described in C. sativus, including powdery mildew and virus resistance, leaf morphology, and parthenocarpy, though molecular markers are available for few.