Issue link: http://winesandvines.uberflip.com/i/63937
GRAPE GRO WING eric Wada finds v. arizonica in the chiricahua mountains of arizona. and it was hybridized with V. riparia and V. rupestris in Europe to produce hybrids that were lime tolerant and easy to propagate. rootstock use in california Vinifera moved from Mexico into California (and New Mexico) in the 1700s and later from Europe via the eastern United States. Phyl- loxera was present on European and eastern American vines. Devastated by phylloxera, California growers began trials with European rootstocks by the 1890s. They tested about 60 rootstocks for adaptation to a large array of sites and ability to produce vigorous vines with good crops, but they didn't establish controls for phylloxera resistance. In those days, most vineyards used limited flood irrigation or were dry-farmed. Growers used a limited range of rootstocks from an initial set of about 60. AxR1 and St. George predominated, but Freedom and Harmony, 5C, 3309C and 110R also were planted. Vinifera x rupestris rootstocks like AxR1, 1202C and 93-5C thrived, as did St. George. Today there are many more rootstocks to choose from. About 20 are available, but Walker said that 101-14Mgt and 1103P predominate. The close-spacing trend continues, and 420A, 3309C, Riparia Gloire and 1616C are used in those cases. As interest in drought adaptation grows, 110R, 1103P and 420A are suitable, while Freedom and Harmony are popular in the San Joaquin Valley. Walker said that 5C and 5BB are underutilized. V. berlandieri x V. rupestris rootstocks were developed for drought and lime tolerance in warmer, drier parts of Europe. Most are shrubby mother vines that produce short canes and many laterals. They have deeper root systems to avoid drought as well as good phylloxera resistance but limited nematode resis- tance. Some are difficult to root and graft. 110R is an example of a V. berlandieri x V. rupestris hybrid. It is a brushy mother vine with short canes and abundant laterals. It is moderate to high in vigor, yet the lowest of the berlandieri x rupes- tris group. It is susceptible to nematodes and slow to establish, but 110R shows more vigorous growth after four to five years. It does best on low-vigor sites and exhibits moderate rooting and grafting success. It is intolerant of the viruses that induce graft failure. Another V. berlandieri x V. rupestris hybrid, 1103P, has relatively high vigor—between 110R and 140Ru—moderate nematode resistance and good salt tolerance. It is widely used in California because it roots and grafts well, and 1103P produces more graftable canes. It is adaptable but performs better on low- vigor sites or large canopy trellis and spacing systems. 140Ru, another V. berlandieri x V. rupestris hybrid, has the highest vigor of the group but is susceptible to nematodes. It is rarely used in California but is good for shallow limestone soils in drought-prone areas where high vigor is needed. It has brushy Wines & Vines MAY 2012 73