Linkage analysis of potyvirus resistance alleles in cucumber

Abstract

The cucumber (Cucumis sativus L.) line TMG-1 is resistant to at least four related potyviruses including zucchini yellow mosaic virus (ZYMV), watermelon mosaic virus (WMV), and the watermelon strain of papaya ringspot virus (PRSV-W). Resistance to ZYMV is due to a single recessive gene (zym), PRSV-W to a single dominant gene (Prsv-2), and WMV to two separable factors. One WMV resistance factor (wmv-2) is expressed in the cotyledon and throughout the plant. The second, which results from an epistatic interaction between two genes (wmv-3, Wmv-4), is expressed only in true leaves. We tested for linkage relationships between these virus resistance loci and an array of morphological, isozyme, and fungal disease resistance loci. Linkages were detected between resistance to WMV and ZYMV, between the cotyledon-expressed resistance to WMV (wmv-2) end the F locus for gynoecious sex expression (linkage group I), and between resistances to PRSV-W (Prsv-2) and ZYMV (zym) and bitterfree cotyledon (bi; linkage group I). The proposed sequence and map distances on linkage group I are Prsv-2/zym - 28 cM - bi - 34 cM - F - 33 cM - wmv-2.