Nitrogen Fertilization and Rootstock Effects on Wood Maturation and Dormant Bud Cold Hardiness of cv. Chardonnay Grapevines

¹ Virginia Agricultural Experiment Station-Winchester, VPI and SU, 2500 Valley Ave., Winchester, VA 22601
² Department of Horticultural Sciences, Cornell University, NYSAES, Geneva, NY 14456.

Two rootstocks and three nitrogen fertilization rates were evaluated for their effects on wood maturation, bud survival, and bud cold hardiness of cv. Chardonnay grapevines. Nitrogen fertilizer, applied at up to 84 kg/ha/ year, had little or no effect on those responses. Vines grafted to cv. Elvira rootstock demonstrated more complete wood maturation than vines grafted to cv. Couderc-3309 rootstock. The degree of wood maturation was apparently an indirect consequence of rootstock effects on vine size and canopy density. Bud mortality due to low temperature exposure in the field was slightly greater for vines grafted to Couderc-3309 than for vines grafted to Elvira. Artificial freezing assays did not reveal consistent rootstock effects on scion bud cold hardiness when buds were collected from visually mature nodes.

Key words: nitrogen, rootstock, cold hardiness, wood maturation

Submitted on February 16, 1988