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  • Author or Editor: Gunawati Gunawan x
  • Journal of the American Society for Horticultural Science x
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Muscadine grape (Vitis rotundifolia) is the first native North American grape to be domesticated. During the past century, breeding programs have created a large collection of muscadine cultivars. Muscadine cultivars are usually identified by evaluating morphological traits and checking breeding records, which can be ambiguous and unauthentic. During this study, simple sequence repeat (SSR) markers were used to generate DNA fingerprinting profiles to identify muscadine cultivars and verify their reported pedigrees. Eighty-nine Vitis accessions were genotyped using 20 SSRs from 13 linkage groups. From these, 81 unique subgenus Muscadinia accessions were identified, and a core set of five SSR markers was able to distinguish all of them. Eighteen misidentifications were found, and five previously unknown accessions were matched with cultivars in the dataset. The profiles of 12 cultivars were not consistent with their reported parentage–progeny relationships. Genetic diversity was analyzed at four levels: all V. rotundifolia cultivars (N = 67); current cultivars (N = 39); historical cultivars (N = 28); and wild V. rotundifolia accessions (N = 9). There was substantial genetic diversity in both wild and historically cultivated muscadines. The principle coordinate analysis (PCoA) showed clear separation among subgenus Vitis cultivars, wild muscadine accessions, and cultivated muscadines, with PCoA1 and PCoA2 explaining 11.0% and 9.3% of the total variation, respectively.

Open Access

Stenospermocarpic seedlessness from Vitis vinifera L. is being introgressed into muscadine grape (Vitis rotundifolia Michx.) germplasm through the use of a cross-fertile hybrid of the two species. Recently, a sequence-tagged site (STS) molecular marker, p3_VvAGL11, has been developed which enables detection of the dominant allele controlling stenospermocarpic seedlessness in V. vinifera. This marker was evaluated in six Euvitis Planch. × Muscadinia Planch. hybrid progenies to determine its association with seedlessness in this material. The presence of the 214-bp seedlessness-associated p3_VvAGL11 allele in seedling vines resulted in a nearly 3-fold reduction in mean seed fresh weight (MSFW) and significantly reduced mean seed weight per berry (MSWB), percent berry weight composed of seed (BWCS), and mean berry weight (MBW). When the lack of lignified seed was used as the determinant of seedlessness, the p3_VvAGL11 marker was able to correctly judge seedlessness in ≈85% of the progeny. Analysis of seedlessness in the progenies was hampered by poor vigor and fruiting ability of the hybrid seedlings. The p3_VvAGL11 marker shows potential to speed the introduction of the stenospermocarpic seedlessness into Muscadinia germplasm by identifying seedless progeny at the seedling stage.

Free access