Submitted to: Cucurbitaceae Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/1/2014
Publication Date: 10/16/2014
Citation: Weng, Y. 2014. Molecularly tagged genes and quantitative trait loci in cucumber. Cucurbitaceae Proceedings. Paper No. 48.
Technical Abstract: Since the release of the cucumber draft genome, significant progress has been made in molecular mapping, tagging or cloning of horticulturally important genes and quantitative trait loci (QTLs) in cucumber, which provides the foundation for practicing marker-assisted selection in cucumber breeding. In this paper, I reviewed genetic and applied genomics resources so far developed in cucumber, and summarized molecularly tagged genes and QTLs for traits in the following categories: disease resistances (for anthracnose, angular leaf spot, downy mildew, Fusarium wilt, powdery mildew, target leaf spot, and viral pathogens); traits for the hypocotyl, cotyledons and true leaves (size, shape, color, and hypocotyl length), plant architecture (lateral branch number, height, compact, internode length, trichomes, growth habit); traits related with flowers (flowering time and node positions, pistillate flower numbers, sex determination) and immature or mature fruits (size, shape, number, weight, skin color, flesh color, spine color/density/number, parthenocarpy, bitterness), and finally, seed-related traits (number, size and weight). For each trait, the associated markers and approximate chromosomal locations on a high-density linkage map were presented. The molecularly mapped genes and QTLs were predominantly located in chromosomes 5 and 6 with almost none in chromosome 7. Among the 145 genes documented in the 2010 Cucumber Gene Catalogue, ~50 have been tagged with molecular markers, more than 25 are in progress; and most of the remaining mutants are reported to have lost. Compared with many other specialty crops, available mutants in cucumber are very limited. Future directions are discussed in the context of advancing marker-assisted cucumber breeding.