NFLUENCE OF GREENHOUSE MAINTENACE TREATMENTS ON GROWTH OF SEEDLING GRAPEVINES (Vitis spp.)

Vegetative clonal propagation of scions and rootstocks represent the commercial method of grapevine production; currently, techniques such as hardwood rooting, grafting, and tissue culture are readily exploited by the nursery and grapevine industries. Seedlings of highly heterozygous grapevines are not true to type, as a result they are not utilized in the mass production of planting stock for commercial grape vineyards. However, seedling growth and quality is key for plant breeding programs initiating thousands of unique seedlings each year. To investigate treatments for their impact on diverse interspecific cold-hardy grapevines, seedlings were grown under greenhouse conditions. Four weeks after transplant, seedlings were cut back to one true node (CUT), leaf thinned (LT), or left as untreated control vines (Control). Eight weeks after treatment, plants were analyzed for total node number, periderm encompassed nodes, lateral shoot number, and total number of base stems. Control and LT vines had more periderm encompassed nodes and total nodes than CUT vines, while CUT vines had the highest number of shoots arising from the base nodes of the vine.