A Grape Rootstock Trial in the Napa Valley a Nine-Year Progress Report of Three Stocks on Bale Loam Soil

¹ Department of Viticulture and Enology University of California, Davis

An experimental planting of 22 fruiting varieties of wine grapes was established on three phylloxera-resistant rootstocks in the Napa Valley, near Oakville, California. The trial was located on Bale loam soil, which is representative of the more fertile grape-growing soils of the north coastal grape-growing region of this state.

This is a report of progress on observations made after nine years of growth, the block having been planted in the spring of 1948. Records for three years on vigor, yield, and fruit quality show distinct differences between the performance of the scion varieties on the three rootstock varieties Rupestris St. George, Aramon x Rupestris Ganzin #1, and Berlandieri x Rupestris 99-R.

Their behavior at this early age is not a measure of their ultimate performance but still can be used as a tentative measure of their suitability for this important wine grape area of California.