Cane and Bud Hardiness of Selected Grapevine Rootstocks

¹ Department of Horticulture, Michigan State University, East Lansing, MI 48824.

Controlled freezing tests were used to evaluate the cold hardiness of cane and bud tissues of the grapevine rootstocks Kober 5BB (5BB), Couderc 3309 (C-3309), and Selection Oppenheim No. 4 (SO4) for three dormant seasons. T₅₀ values were compared for each sampling date. Bud hardiness differences between rootstocks were variable. Cane hardiness for all rootstocks was similar through November, with C-3309 acclimating more rapidly in two of the three dormant seasons. C-3309 was more hardy than 5BB on a number of dates throughout the study. From December through March, C-3309 always had the most hardy and 5BB the least hardy canes in all three dormant seasons.

Key words: rootstocks, cold hardiness, controlled freezing, Couderc 3309, Kober 5BB, Selection Oppenheim No. 4, freezing stress

Submitted on February 5, 1987