Larry Bettiga*
*University of California Cooperative Extension, 1432 Abbott Street, Salinas, CA, 93901 (lbettiga@ucdavis.edu)

Plant material used can be a critical factor influencing early vine development and productivity. The objective of this study was to evaluate nursery stock for their potential to advance vine development and yield. In 2016, a trial was established in a Chardonnay vineyard in the Salinas Valley of California to compare standard, 30 cm-long dormant bench grafts to 90 cm-tall bench grafts. Vine growth and yield parameters were measured from 2016 to 2021. The treatments were: 1) field-grown dormant, 30 cm; 2) tall green-growing potted, 90 cm; 3) tall dormant-potted, 90 cm; 4) tall dormant field-grown, 90 cm; and 5) tall dormant field-grown, 90 cm, un­trimmed roots. Standard vines were trained to a single trunk in the first year. Cordon training started in the first year for all treatments where growth was adequate. The dormant tall field-grown bench grafts produced vines with larger-diameter trunks at the end of the first year, tall potted vines were intermediate, and the standard bench grafts were the smallest. The length of cordon development in the first year was greatest for tall dormant potted vines, intermediate for tall field-grown vines and not possible for most of the standard or tall green-growing vines. Yield in the second year was greatest for dormant tall vines, intermediate for standard vines, and not possi­ble for tall green-growing vines due to the lack of cordon development. In the third and fourth years, yield was greater for tall dormant bench grafts, intermediate for standard vines, and lowest for green-growing vines. By the fifth year, all plant material had similar yields. Higher yield of dormant tall vines was possible due to the greater development of the permanent structures of the vines, which increased the capacity to produce crop in the early production years.

Funding Support: Various donors