BEJING, CHINA--Watermelon is an important crop in China, where 68.2 million tons of the fruit were produced in 2009. China is the world's largest producer of watermelon, accounting for 67.7% of global production. Most watermelon varieties grown in China were bred and selected for their good performance under irrigated field conditions, but in recent years drought conditions have challenged China's watermelon growers. For example, production in China's Gansu province alone has declined 50% as a result of severe drought. To alleviate the stresses of drought-stricken regions, researchers are looking to the United States for drought-tolerant watermelon varieties.
A number of drought-tolerant varieties have been developed for other crops, but only limited information is available for watermelon. According to the authors of a study published in HortScience, identification of watermelon germplasm with drought tolerance properties is vital. Global climatic conditions have created a critical need to identify genetic sources for potential drought tolerance.
Researchers from the National Engineering Research Center for Vegetables, Beijing Academy of Agricultural and Forestry Sciences, and the U.S. Department of Agriculture–Agricultural Research Service (USDA–ARS) published the results of their evaluation of 820 accessions of USDA watermelon breeding lines in HortScience. The varieties were studied under extreme water stress conditions in a greenhouse and evaluated for drought tolerance.
Using fast clustering analysis, the scientists assigned watermelon to four groups: tolerant, intermediate tolerant, moderately sensitive, and sensitive. Though significant variations in drought tolerance were observed in the Citrullus germplasm collections, the researchers identified 25 accessions as potential sources of tolerance to drought. They noted that the most drought tolerant Citrullus germplasm, including 13 Citrullus lanatus var.lanatus and 12 Citrullus lanatus var.citroides accessions, originated from Africa.
These genetic materials could be used for rootstock breeding or for developing drought tolerant watermelon cultivars. "Once developed, these cultivars would be readily accepted by the resource poor, rain-fed, and small holder farmers in China," the researchers said.
The complete study and abstract are available on the ASHS HortScience electronic journal web site: http://hortsci.ashspublications.org/content/46/9/1245.abstract
Founded in 1903, the American Society for Horticultural Science (ASHS) is the largest organization dedicated to advancing all facets of horticultural research, education, and application. More information at ashs.org
Screening the USDA Watermelon Germplasm Collection for Drought Tolerance at the Seedling Stage
Haiying Zhang, Guoyi Gong, Shaogui Guo, Yi Ren, Yong Xu, and Kai-Shu Ling
HortScience 46:1245–1248. [Abstract][Full Text][PDF]