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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Publications at this Location » Publication #336939

Research Project: Genetic Enhancement of Allium, Cucumis, and Daucus Germplasm

Location: Vegetable Crops Research

Title: Spontaneous polyploidization in cucumber

Author
item Ramirez-madera, Axel
item Miller, Nathan
item Spalding, Edgar
item Weng, Yiqun
item Havey, Michael

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/30/2017
Publication Date: 4/13/2017
Publication URL: http://handle.nal.usda.gov/10113/5700717
Citation: Ramirez-Madera, A.O., Miller, N.D., Spalding, E.P., Weng, Y., Havey, M.J. 2017. Spontaneous polyploidization in cucumber. Theoretical and Applied Genetics. 130(7):1481-1490. doi: 10.1007/s00122-017-2903-7.

Interpretive Summary: Cucumber breeders and growers have observed off-type plants in hybrid cultivars with darker green leaves with pronounced serration, shorter stature, and misshaped fruits with non-viable seeds. Field-grown plants were identified showing these characteristics and flow cytometry revealed that these plants often had multiples of the normal chromosome number (polyploids). We produced seed of inbred lines of cucumber in different environments and used flow cytometry to establish the ploidies of field and greenhouse-grown plants. We identified individual plants that were mosaic (possessing nuclei of different ploidies in single leaves) and chimeric (on different parts of the same plant). Our results provide evidence of reduplication of chromosome numbers without cell division in cucumber, and that it is an ongoing and dynamic process. We measured the ploidy levels of multiple leaves on 1,422 plants and the overall relative frequency of spontaneous polyploidy was 2.2%. Seed and seedling traits were not accurate predictors of eventual polyploid plants, and we recommend that cucumber producers rogue plants based on stature and leaf serration to remove potential polyploids. These results will be of interest to breeders, seed industry, and growers of cucumber to avoid losses due to spontaneous polyploid plants.

Technical Abstract: Cucumber breeders and growers have observed off-type plants in hybrid cultivars with darker green leaves with pronounced serration, shorter stature, and misshaped fruits with non-viable seeds. Field-grown plants were identified with these characteristics and flow cytometry revealed that these plants were often polyploids. We produced seed of recombinant inbred lines (RILs) of cucumber in different environments and used flow cytometry to establish the ploidies of field and greenhouse-grown plants. We identified individual plants possessing nuclei of different ploidies in single leaves (mosaic) and on different parts of the same plant (chimeric). Our results provide evidence of endoreduplication and polysomaty in cucumber, and that it is an ongoing and dynamic process. We measured the ploidy levels of multiple leaves on 1,422 plants and the overall relative frequency of spontaneous polyploidy was 2.2%. Seed and seedling traits were not accurate predictors of eventual polyploid plants, and we recommend that cucumber producers rogue plants based on stature and leaf serration to remove potential polyploids.