In Vitro Somatic Embryogenesis from Stamens of ‘Trincadeira’, a Portuguese Vitis vinifera L. Cultivar

Stamens collected from vineyard-growing plants were used as starting material to induce in vitro somatic embryogenesis in ‘Trincadeira’, a Portuguese grapevine Vitis vinifera cultivar. Stamens filaments bearing anthers enclosing microspores in the binucleate stage were the most responsive for embryogenesis induction. Culture media with low concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) (5 µM) and 6- benzylaminopurine (BAP) (1 µM), presented the highest efficiency for embryogenic calluses formation. Calluses, formed at the stamen excision zone, with white to paleyellow colour and granular appearance, revealed embryogenic competence. Embryo formation was achieved in Nitsch and Nitsch (1969) basal medium supplemented with 1 or 5 µM α-naphtaleneacetic acid (NAA). Embryos were converted into plants true to type that were successfully acclimatized and field planted. Plant ploidy, evaluated by flow cytometry, revealed that all the plants tested presented 2n=2x=38 chromosomes