UC Davis

The accumulation of salts in plant rootzones, known as “salinization,” is often a gradual process that can degrade soil structure and cause permanent plant damage. Salinization caused by ever increasing water demands and an increasingly dry climate is becoming problematic for agriculture in semi-arid to arid regions, including California’s Central Valley, which produces about one-quarter of the United States' food supply and almost half of its nuts and fruits, including grapes, according to the USGS California website (https://ca.water.usgs.gov). While grapevines are considered moderately salt tolerant (Walker et al. 2002), the current rate of salinization in many of California's vineyards is contributing to reduced crop yields and lower fruit quality (Keller 2020). Once symptoms of salt toxicity appear on the leaves, vine growth and crop yield may already be in serious decline (Fort and Walker 2011). To prevent salt toxicity from occurring in grapevines, the Walker Lab at UC Davis is applying traditional plant breeding techniques to some of the native population of wild North American grapevine species to improve the salt tolerance of commercial rootstocks (Fort et al. 2013). In recent years, the Walker Lab discovered a wild grapevine species called Vitis acerifolia 9018, which has consistently proven to be more salt tolerant than the most salt tolerant commercial rootstocks (Chen 2021). These physiological traits could be bred into existing popular commercial rootstocks to improve their salt tolerance. The research for this thesis was performed to observe the stress response and compare the salt tolerance of the recently discovered salt tolerant wild rootstock V. acerifolia 9018, against commercial rootstocks widely planted in California and other salinization-affected places, including Ramsey, 1103 Paulson and 140 Ruggeri.