Breeding Salt and Drought Tolerant Rootstocks Andy Walker
Acknowledgements California Grape Rootstock Improvement Commission / California Grape Rootstock Research Foundation CDFA NT, FT, GV Improvement Advisory Board California Table Grape Commission American Vineyard Foundation E&J Gallo Winery Louis P. Martini Endowed Chair in Viticulture Mark Lyons
Rootstock Origin First developed to address grape phylloxera in the late 1800s The French came to the US to collect species resistant to phylloxera Took back cuttings of many, but only V. riparia and V. rupestris rooted well from dormant cuttings Later added V. berlandieri for lime tolerance berl x rup 110R, 1103P and 140Ru
V. riparia Missouri River
V. rupestris Jack Fork River, MO
V. berlandieri Fredericksburg, TX
History of rootstock use in California Most vineyards dry-farmed or with limited irrigation vinifera x rupestris rootstocks thrived AXR#1, 1202C, 93-5C St. George did well too
Which rootstock to choose? riparia based shallow roots, water sensitive, low vigor, very early maturity: 5C, 101-14, 16161C (3309C) rupestris based broadly distributed roots, relatively drought tolerant, mod to high vigor, midseason maturity: St. George, AXR#1, 1202C, 1103P
Which rootstock to choose? berlandieri based deeper roots, drought tolerant, higher vigor, delayed maturity: 110R, 140Ru (420A, 5BB) Site trumps all soil depth, rainfall, soil texture, water table
Why not just use St. George? Easy to propagate Expansive roots somewhat drought tolerant Roots exclude salt Tolerates virus diminishes expression But very susceptible to most nematodes; supports high phylloxera numbers on root tips (nodosities); no lime tolerance
What is needed? Understanding drought adaption vs drought tolerance Can we uncouple rooting depth from drought adaptation/tolerance? What is the relationship of seasonality to rooting depth and rootstock parentage?
Root architecture The root system of rootstocks can be both deeply penetrating and shallow reflects its water needs and utilization The density of roots in the soil profile also varies Evenly distributed Primarily deep Primarily shallow
420 A 110 R depth (cm) depth (cm) 20 40 * * 20 40 * * 60 80 60 80 * * + * 100 120 140 160 180 100 120 140 160 180 * * 200 * + = < 2 mm = > 2 and < 5 mm = > 5 and < 12 mm = > 12 mm 200 * + = < 2 mm = > 2 and < 5 mm = > 5 and < 12 mm = > 12 mm
Root architecture The root architecture and density of the deep and surface roots relates directly to nutrient and water uptake Some plants hydraulically lift water from deep in the soil profile to keep the surface roots active These characters vary and allow rootstocks to be more or less drought tolerant and impacts their ability to take up nutrients
Root architecture differences Mostly deep roots: Ramsey, 140Ru, 1103P, 110R Broadly distributed roots: 1103P, Freedom, Harmony, St. George, O39-16, 5BB, 420A Mgt Primarily shallow roots: 101-14 Mgt, Schwarzmann, 101-14 Mgt, 5C, 420A, 16161C
Breeding Rootstocks to Tolerate Drought, and Control Growth and Phenology In collaboration with Andrew McElrone Root architecture shallow to deep rooting angles Root density two tiered to even distributions Hydraulic lift Water use efficiency / productivity Mike Anderson and Jim Wolpert s trials associate characters with drought tolerance Control of vigor and leaf longevity New campus plot: 7 rootstocks, 2 scions, 5 irrigation levels
Salt and Drought Tolerance Salt and drought tolerant rootstocks exist Need better forms of tolerance and a means of uncoupling root architecture Understand exclusion vs. avoidance Salt tolerance assay successfully modified to match Australian field data
A fritted-clay based assay
Root angle / Root architecture Assay: Background V. riparia V. riparia x V. rupestris V. rupestris Guillon 1905
Ramsey Riparia Gloire
Ramsey Riparia Thompson from hydroponics
Root architecture Parallel rooting patterns in grapevine rootstocks SSR map completed for segregating population; ready for DNA marker identification Riparia Ramsey
Drought Tolerance What anatomical traits influence drought tolerance? Root angle Xylem diameter / distribution Storage capacity Stomatal distribution
Drought Tolerance Vessel Area Ratios Cortex Anatomical Differences Ramsey Riparia Ramsey Riparia Ramsey Riparia
V. riparia V. rupestris V. berlandieri
Germplasm Discovery Sourcing raw material for further evaluation Wild grapevines in southwest U.S. May be adapted to hot, dry, saline conditions Many promising individuals already found Very diverse, complicated group we need more information to efficiently select material for breeding
Salt Tolerant Germplasm Salt flat NW of Las Vegas, NV V. arizonica in Arizona
Germplasm Discovery Genetic / Geographic Analyses - Good Salt Excluder - Poor Salt Excluder Overall characterization of the population for targeted collection and effective germplasm selection
The Eco-Genetics of Chloride Exclusion Spatial Genetics Use GIS tools to correlate phenotypic, taxonomic, and geographic data Define natural ranges and hybrid zones Locate possible hotspots for chloride exclusion or other traits Principal Component Analysis If the GIS tools point to specific soil or climate characteristics, we will collect more specific data in those areas to perform a PCA
Impact of rootstocks on phenology There is an impact of rootstocks on crop ripening which is more pronounced under limited irrigation or on shallow soils. Some studies have found differences of 7 to 10 days Late maturing rootstocks: 420A, 140Ru Early rootstocks: 5C, 101-14, 1616C, Riparia Gloire Lots of variation in between
Thanks!