Flowering in Vitis: Conversion of Tendrils into Inflorescences and Bunches of Grapes

Inflorescences and fruits with viable seeds were produced in place of tendrils in plants of Vitis vinifera L. cv. "Muscat of Alexandria" and in a staminate hybrid grapevine (Vitis vinifera × V. rupestris Scheele) following repeated applications of 10—20 μl of 50—200 μM 6-(benzylamino)-9-(2-tetrahydropyranyl)-9H-purine (PBA) to apices. Young leaves, shoot tips and axillary buds were removed before the PBA treatments were commenced. The number and weight of berries produced by inflorescences derived from tendrils was closely correlated with the number and area of leaves retained. When application of PBA was continued after floral initiation there was formation of fused flowers and cleistogamous pollination.