Development and Characterization of Molecular Markers Associated with Female Plants in Muscadine Grape

Abstract

<jats:p>Muscadine (<jats:italic>Vitis rotundifolia</jats:italic> Michx.) vines may be male (M), female (F), or hermaphroditic (H). Male flowers have only filaments and anthers, whereas female and hermaphroditic flowers are morphologically perfect. Female flowers are distinguished from hermaphroditic flowers by their reflexed stamens (as opposed to upright) and nonfunctional pollen. Primers derived from previously identified candidate genes located at the sex locus of <jats:italic>Vitis vinifera</jats:italic> L. were used to generate amplicons from M, F, and H muscadine cultivars. Sequence analysis of the amplicons revealed insertion/deletion (indel) polymorphisms in a trehalose-6-phosphate phosphatase (TPP) gene (VR006) and a WRKY transcription factor 21 gene (VR009). Primers were designed to create diagnostic markers for each indel polymorphism. Associations between the marker alleles and the plant sex trait were examined in a wide range of muscadine germplasm and in segregating populations derived from F × H, F × M, and H × H crosses. VR006 produced a codominant marker that was able to differentiate the female-associated allele from the male- and hermaphroditic-associated alleles. The marker was able to detect female plants and will be suitable for screening breeding program progenies. VR009 was able to detect the presence of the female allele in most germplasm, but a crossover event appears to have separated the marker from the sex locus in some germplasm. As shown in previous muscadine genetic studies, H × H-derived populations produced male seedlings. Marker analysis of these populations indicates that male flowers only occur in seedlings which are heterozygous for F- and H-associated marker alleles and inheritance of flower type in muscadine remains unclear.</jats:p>

Haplotyping the Vitis collinear core genome with rhAmpSeq improves marker transferability in a diverse genus

“…vinifera is hermaphroditic 32 . The region around 5Mbp on chromosome 2 has been identified in several linkage mapping and population genetic studies, and the boundary of the sex locus and the sex determining genes were proposed but are still under debate [32][33][34][35][36] . Here, we used the sex locus to assess the performance of our rhAmpSeq markers in genetic mapping.…”

Glutathione S-transferase: A Candidate Gene for Berry Color in Muscadine Grapes (Vitis rotundifolia)

“…The most common challenge for muscadine breeding programs is to increase fruit quality while retaining disease resistance and vine vigor. Breeding efforts are currently focused on selection for seedlessness, hermaphroditism, and stable berry color during processing (Lu et al 1993;Conner and MacLean 2013;Xu et al 2014;Conner et al 2017;Lewter et al 2019). Berry color of muscadine grapes is very important especially for wine and juice industry as poor color stability can result in reduced quality of processed products (Morris and Brady 2004;Vasanthaiah et al 2011).…”

Muscadine (Vitis rotundifolia Michx., syn. Muscandinia rotundifolia (Michx.) Small): The Resilient, Native Grape of the Southeastern U.S

“…While the muscadine sex locus mapped to a region on chromosome 2 associated with the sex locus of V. vinifera subsp. sylvestris [42], genetic control of the sex expression in some backgrounds of muscadine differ from V. vinifera [43].…”