Morphological and physiological aspects of Vitis spp. Flower for breeding purposes

Flowers of 6 species of Vitis (V. candicans Engelm., V. champinii Planch., V. coriacea Shuttew., V.palmata-rubra Vahl., V. rupestris 'du Lot' Scheele, V. solonis Prince) were examined for morphology of gynoecium and androecium in the physiologically female or male entities. These species, indigenous of America, are interesting for resistance to some parasites (i.e. Oidium, phylloxera, vine mildew) and to pedoclimatic conditions. Observations were carried on pollen grains and pistils by LM and SEM. Pollen of physiologically male species (V. candicans and V. rupestris 'du Lot') was prolate and tricolpate and showed high germinability (about 80%) while pistils were not well developed. Pollen grains of physiologically female species were subprolate, inaperturate and did not germinate, while pistils were well developed. The examined entities are a genetic resource useful for crossings and the constitution, for example, of new root-stocks.