Somatic embryogenesis from leaves and anthers of grapevine

Abstract

Leaves less than 5 mm long from greenhouse-grown and in vitro-grown plants of Vitis vinifera cultivar ‘Cabernet Sauvignon’ and greenhouse-grown V. rupestris ‘St. George’ (synonym ‘du Lot’) and PI 200692 produced somatic embryos when cultured on Nitsch and Nitsch (NN)- and Murashige and Skoog (MS)-based media. Similarly, translucent-pale green anthers from greenhouse-grown and vineyard-grown plants of V. vinifera ‘Cabernet Sauvignon’, ‘Cardinal’, ‘Grenache’, ‘Sauvignon Blanc’, ‘Thompson Seedless’ (synonyms ‘Sultanina’, ‘Sultana’) and ‘White Riesling’, V. rupestris ‘St. George’ and PI 200692 and V. vinifera × rupestris ‘Ganzin No. 1’ also produced somatic embryos on NN or MS media. Only those leaves cultured on solid media exhibited embryogenic competence, and this occurred preferentially when explants were buried beneath the medium surface. Anthers initiated somatic embryos on solid medium and also when transferred from liquid to solid. Several growth-regulator combinations stimulated somatic embryogenesis from both leaf and anther tissues and one, NN supplemented with 1.0 mg l −1 2-naphthoxyacetic acid and 0.2 mg l −1 6-benzylaminopurine, was effective with explants of all genotypes which proved embryogenically competent, but was not always associated with the optimal response. Genotype, explant type and source, culture procedure and culture medium composition all influenced the embryogenic response, as did the condition of the donor plants. Proliferation of embryogenic tissue occurred when pieces were cultured on fresh medium of the same formulation as that which induced somatic embryogenesis from explants. With regular transfers, such tissue maintained its embryogenically competent state for over 1 year. Isolation and incubation of somatic embryos on media with and without growth regulators stimulated apical root and shoot axis growth, resulting in plant development. Plants were readily transferred to soil and appeared morphologically normal.