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Research Project: Characterization, Etiology, and Disease Management for Vegetable Crops

Location: Vegetable Research

Title: Quantitative trait loci mapping of resistance to Fusarium oxysporum f. sp. niveum race 2 in Citrullus lanatus var. citroides using genotyping-by-sequencing

Author
item Branham, Sandra
item Levi, Amnon
item Farnham, Mark
item Wechter, William - Pat

Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/28/2016
Publication Date: 1/15/2017
Citation: Branham, S., Levi, A., Farnham, M.W., Wechter, W.P. 2017. Quantitative trait loci mapping of resistance to Fusarium oxysporum f. sp. niveum race 2 in Citrullus lanatus var. citroides using genotyping-by-sequencing (GBS). Plant and Animal Genome Conference. W234.

Interpretive Summary: N/A

Technical Abstract: One of the most devastating watermelon diseases worldwide, Fusarium wilt, is caused by Fusarium oxysporum f. sp. niveum (Fon). Spread of the particularly virulent Fon race 2 in the United States, coupled with the lack of resistance in edible cultivars of the sweet cultivated watermelon Citrullus lanatus var. lanatus (Cll) poses a serious problem. Years of selection for desirable horiticultural traits in Cll has eroded genetic diversity, including the loss of many disease resistance genes. The wild subspecies of watermelon, C. lanatus var. citroides (Clc), harbors a wealth of genetic diversity including resistance to many diseases and is, therefore, essential to continued watermelon improvement. We used genotyping-by-sequencing (GBS) to generate the first intra-variety Clc genetic map with an F2:3 population (N=173) segregating for Fon race 2 resistance. A total of 2,495 binned SNPs formed 11 linkage groups with an average distance of 0.7 centiMorgans (cM) between SNPs and a total map length of 1,798.9 cM. One major and four minor QTL explained 69.3% of the variation in resistance. The major QTL was delimited to a 1.2Mb interval of chromosome 9, which collocated with one putative disease resistance gene.