Anthers and ovaries of Vitis longii 'Microsperma' produced embryogenic callus when cultured on solidified Murashige and Skoog medium with 5/~M 2,4-dichlorophenoxyacetic acid (2,4-D) and 1 #M benzyladenine (BA). The initial callus was short-lived. However, long-term embryogenesis from callus was maintained through serial transfers by careful selection of clustered embryos with subtending callus. Alternatively, long term culture maintenance was through secondary embryogenesis which occurred directly from previously formed embryos on medium lacking growth regulators. Somatic embryos were white, exhibited frequent pluricotyly and tended to be larger than zygotic embryos. Histology of embryogenic callus demonstrated the presence of lipidlike substances and abundant starch. Somatic embryos were attached to callus by narrow to wide suspensor-like structures and possessed typical epidermal, cortical, and vascular tissue. Embryo cells contained abundant lipid-like accumulations but no starch. Embryos germinated when placed on medium containing 1 #M BA and produced plants of normal appearance.

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Ovules of seedless bunch grapes (Vitis spp.) fertilized by controlled pollination increased in size during berry development. More ovules cultured 10 days or 60 to 70 days after pollination became brown compared to those cultured at 20 to 40 days. Cultured ovules developed with and without endosperm. Globular to torpedo stage embryos were recovered. More embryos and plants were recovered from ovules cultured at 40 or 60 days than at 10 or 20 days after pollination. Pollen parent significantly affected both embryo and plant recovery at certain sampling times. BA incorporated into medium significantly increased embryo germination percentage. Electrophoretic analysis of glucosephosphate isomerase in progeny showed that 67% to 88% were hybrids of controlled crosses. Of four vines that fruited thus far, two were seedless. Seedless progeny had smaller seed traces than either parent. Chemical name used: N-(phenylmethyl) -1H-purin-6-amine (BA).

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Under conditions favoring Pierce’s disease (PD) infection in the vineyards at Leesburg, Florida, 222 Euvitis scion clones, 60 Muscadinia clones, and 49 Euvitis rootstock clones were grown and observed for PD symptoms for 8 or more years. There were 21 PD-resistant scion clones, 20 of which derived their resistance from 1 or more of 4 species: Vitis smalliana Bailey, V. simpsoni Munson, V. shuttleworthi House, and V. aestivalis Michx. There were 22 PD-resistant Muscadinia clones, predominantly of V. rotundifolia Michx. background. There were 15 Euvitis rootstock clones with resistance derived from one of six native species: V. candicans Engelm., V. champini Planch., V. cordifolia Michx., V. shuttleworthi, V. simpsoni, and V. smalliana.