The effect of the orientation of stem segments of grapevine (Vitis vinifera) cv. Chardonnay on callus development in vitro

Callus induction and formation were successfully achieved using stem segments of grapevine cv. Chardonnay. Nodal stem segments from in vitro plantlets and internodal segments from field-grown plants of grapevine were used. The segments were placed in an inverted and upright position in hormone-free medium or in medium supplemented with 1. 1 mg/l naphthalene acetic acid and 0. 45 mg/l benzyladenine. Firm, compact callus with pro-meristematic clusters was induced on the inverted segments within 10-20 days, while only small calluses and roots appeared on the upright segments. Vascular cells (xylem and phloem) were differentiated and maintained for more than 2 years in consecutive subcultures. The results show that inverting the position of grapevine stem segments in vitro is a simple method for producing firm callus with pro-meristematic clusters.