ARS | Publication request: Screening the USDA watermelon germplasm collection for drought tolerance at the seedling stage

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 6, 2011
Publication Date: September 1, 2011
Citation: Zhang, H., Gong, G., Guo, S., Ren, Y., Xu, Y., Ling, K. 2011. Screening the USDA watermelon germplasm collection for drought tolerance at the seedling stage. HortScience. 46(9):1245-1248.

Interpretive Summary: Watermelon is an important vegetable fruit crop that is cultivated throughout tropical and subtropical regions around the world. China produces the most watermelon and the U.S. ranks fifth in production of this crop. Increasing drought stress which may be due to climate change has caused significant crop losses in western China, Africa and some parts of U.S. In the present study, scientists at the Beijing Academy of Agricultural Sciences in cooperation with an ARS scientist in Charleston, SC, screened over 820 plant introductions from the USDA collection and 246 Chinese breeding lines for drought tolerance, and they identified 25 wild watermelon accessions exhibiting the most drought tolerance. The wild watermelon germplasm with drought-tolerant properties should be useful genetic stocks for plant breeders to develop new drought–tolerant watermelon cultivars. The planting of drought tolerant cultivars may allow farmers to sustainably produce crops even under severe drought stress conditions.

Technical Abstract: Because of the growing threat of global warming, drought stress could severely affect the normal growth and development of crop plants. To alleviate such adverse effect, there is a need to screen watermelon germplasm collections to identify genetic sources for potential drought tolerance. In the present study, 820 accessions of USDA’s Citrullus plant introductions (PIs) and 246 watermelon breeding lines were evaluated for their drought tolerance at the seedling stage under the extreme water stress conditions in greenhouse. Significant variations in drought tolerance were observed in the Citrullus germplasm collections. Using fast clustering analysis, the tested watermelon materials could be assigned into four groups, including tolerant, intermediate tolerant, moderate sensitive and sensitive, respectively. The most drought tolerant Citrullus germplasm, including 13 Citrullus lanatus var. lanatus and 12 C. lanatus var. citroides accessions were originated from Africa. These genetic materials could be used for rootstock breeding or for developing drought tolerant watermelon cultivars.