Somatic embryogenesis from stigmas and styles of grapevine

Summary An in vitro protocol has been developed for callus indiction, somatic embryogenesis, and plant regeneration from stigma-style culture of grapevine. Four different grapevine cultivars (Vitis vinifera L.: cvs. ‘Bombino Nero’, ‘Greco di Tufo’, ‘Merlot’, and ‘Sangiovese’) were tested. Exlants were cultured on Nitsch and Nitsch medium (NN) supplemented with various combinations of 6-benzylaminopurine (BA: 4.5 and 9.0 μM) and β-naphthoxyacetic acid (NOA; 5.0 and 9.9 μM). Sucrose (88 mM) was used as the carbon source. Somatic embryogenesis was induced within 3–7 mo. after culture initiation. Even though explants of different origin (unfertilized ovules and anthers) regenerated somatic embryos, the higher embryogenic potential was observed in stigma and style explants, with the exception of ‘Merlot’, which regenerated somatic embryos only from unfertilized ovules. The percentages of stigma-style explants producing somatic embryos was 7% in ‘Bombino Nero’ (cultured on NN medium supplemented 9.0 μM BA and 9.9 μM NOA). 14% in ‘Greco di Tufo’ (4.5 μM BA and 9.9 μM NOA), and 8% in ‘Sangiovese’ (9.0 μM BA and 9.9 μM NOA). The presence of growth regulators (BA and NOA) in the medium was essential for induction of somatic embryogenesis. Plants were regenerated on hormone-free NN medium containing 88 mM sucrose.