Rootstock Tolerance to Soil Salinity: Impact of Salinity on Popular Grape Rootstocks Grown in Contrasting Soil Types

Summary (by Objective): To date, we have accomplished several major goals: Objective 1: Soil Characterization; Monitor the impact of salt accumulation on soil solution chemistry and nutrient balance. The two vineyard sites were selected based on preliminary soil analyses during Year 1. During Years 2 and 3, we performed additional, detailed chemical and physical analyses of the two contrasting soils. The results of these analyses confirmed the differences in morphology and texture between the two soils, and also revealed differences in cation exchange capacity, hydraulic conductivity, and plant available water. In year 4, we applied a saline solution to the soil through the drip system and sampled the soil solution after the salt application. In Year 5, two additional salt applications will be performed; plant tissue and soil solution will be monitored concurrently in order to determine the relationship between soil properties and plant growth and nutrition. Objective 2: Determine the tolerance of a panel of ten rootstocks to irrigation water containing four different salinity levels. (a) Grafting and planting of 10 rootstocks and own-rooted controls at each of the two vineyard sites. The planting scheme was described in section IV above, and a map of one of the vineyard sites is provided in Appendix A. (b) Monitoring of the plants. As expected, some losses among the grafted rootstocks occurred during the first winter. Missing plants were replaced during Year 2 using additional grafted vines provided by the nursery, which had been designated for this purpose. During the warmest weeks of the summer, supplemental irrigation was given to the developing vines to prevent further losses. Subsequent losses, which were minimal, have not been replaced due to the larger size and maturity of the plants. (c) Application of saline irrigation solution. During Year 4, the irrigation system was locally modified to allow the application of solutions with a salinity level of 1.75 mS, 3.5 mS and 4.5 mS. The saline solution was applied using water-powered non-electric chemical injectors coupled with the drip line, during a single, 30-hour irrigation event that was coordinated with the vineyard management staff. The soil solution was sampled following the irrigation event using suction lysimeters buried at depths of 6 and 12 inches, and the chemical analysis of these solutions is ongoing. Leaves and petioles were again sampled at 2, 4 and 6 weeks after the saline solution was applied. The blade tissues are currently being analyzed for chloride ion (Cl-) content, as a marker for salt uptake by the plant tissue. The samples from week 4 are also being analyzed for other macro and micronutrients, as was done for the bloom and veraison samples. Results of these analyses are anticipated in Spring, 2012. In Year 5, two additional applications of saline solution will be performed and the results intensively monitored.

Physiological Role of Rootstocks in Determining Grapevine Vigor

We have made substantial progress in understanding at least one mechanism involved in determining why grapevines achieve such high vigor in deep fertile soils, even when irrigation water is withheld. This mechanism can be generally defined as hydraulic redistribution and involves the passive movement of water from roots in moist soil zones, under the drip irrigation emitter or from groundwater, to roots in dry surface or subsurface soils outside the emitter zone. We achieved this result by labeling water with 2{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23} deuterium oxide, D2O. We then applied the labeled water through a drip emitter on one side of each of three 5-7 yr-old 420A rootstocks (Vitis berlandieri X V. riparia). We extracted roots and soil from both the labeled side and the dry side of the vine. Using the quantity of isotope found in roots we estimated that nearly 6 to 8{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23} of the water in roots on the dry side of the vine came from the labeled water in the emitter zone. This water was conducted through the grapevine trunk and into roots on the dry side almost immediately (36 h). These observations suggest that the establishment of an extensive root system may contribute to over vigorous vines more than any single physiological trait like nutrient absorption because total root system size probably has more to do with total capacity for nutrient and water absorption than any other single factor. Hydraulic redistribution probably allows vines to sustain roots even during adverse conditions for growth. We are proposing further experiments in this area.

Rootstock Interaction with Cultural Practices

of rootstock affected total vegetative growth and higher pruning formulae resulted in reduced shoot vigor on all rootstocks. Total leaf area per vine averaged 28.1, 16.7, 14.6, 11.0, 9.6, and 4.2 m2 on 1103P, 110R, 3309C, S04, 101-14, and 420A respectively. Shoot lengths averaged 150, 120, 98, and 84 cm at the 4, 8, 12, and 16 bud formulae. Under the extreme pruning formulae and rootstock capacities used in this study, rootstock/pruning interactions were noted for all aspects of vegetative growth except final pruning weight. At low pruning formulae, higher capacity rootstocks produced larger shoots (176cm on 1103P and 110R compared to 118 cm on 420A). Differences in vigor diminished at higher pruning formulae. Total vegetative growth responded curvilinearly to pruning. Leaf area per vine was reduced by 40{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23} at the lowest pruning formula on all rootstocks except 110R. For all rootstocks, it reached a maximum between the 8 and 12 bud/lb formulae and declined slightly thereafter. Rootstock affected yields both through effects on initial vine size and through effects on bud fruitfulness. Yields averaged 13.7, 9.0, 7.2, 4.4, 5.5, and 1.9 per vine for 1103P, 110R, 3309c, SO4, 101-14, and 420A respectively. Larger vines also produced larger clusters with more and larger berries. Cluster weights averaged 105, 101, 93, 88, 94, and 72 gm for 1103P, 110R, 3309c, SO4, 101-14, and 420A, respectively. The number of clusters per shoot varied by rootstock but was less dependent on vine size, averaging 1.79, 1.86, 1.68, 1.68, 1.86, and 1.60 clusters per shoot for 110R, 101-14, 1103P, 3309C, SO4, and 420A. Significant pruning/rootstock interactions existed due to very low fruitfulness on lowest capacity rootstock at the lowest pruning formula. Rootstock and pruning formula affected crop to pruning weight ratio without significant interaction. Crop to prunings ratios were lower on SO4 and 420A than on other rootstocks (3.5, 3.6, 4.8, 5.1, 5.4, and 5.5 on SO4, 420A, 3309C, 101.14, 110R, and 1103P). Crop to pruning weight ratios increased from 2.5 at the 4bud/lb pruning treatment to 6.3 at 16 bud/lb. Significant effects of rootstock, pruning formula, and their interaction were noted for rate of maturation. °Brix on 1103P was delayed at all pruning levels. Fruit from vines on 420A and SO4 was riper than that of vines on 110R, 309C or 101-14. Rootstock, pruning, and their interaction affected maturity solely through differences in crop and vegetative growth.

The independence of rootstock and pruning on vigor was found to break down at extreme capacities and pruning formulae. Further, the response of total vegetative growth to pruning was found to be curvilinear across the broader range of pruning formulae.

Total vegetative growth was dependent on pruning level and vine spacing. Pruning weights declined slightly from 0.9 kg/vine at 3 and 6 bud/m2 to 0.7 kg/vine at 9 bud/m2. Pruning weights increased from 0.65 kg/vine on 1M spacing to 1.2 kg/vine at 2.2m. Vigor was dependent on rootstock, pruning level and vine space. In all cases shoot growth fell to inadequate levels (below 30 gm/shoot) at the highest pruning level of 9 bud/m2. Yields were dependent on rootstock, pruning level, and vine space. With fewer clusters per shoot and setting fewer berries per cluster, 101-14 was less fruitful than 110R. Yields averaged 4.3 and 5.4 kg/vine on 101-14 and 110R respectively. Yields on 5-C were comparable to those of 110R. Yields were dependent on vine space and pruning level through number of shoots retained but reached a maximum at the 6 bud/m2 pruning level due to reductions in clusters per shoot and berry weight. At pruning levels of 3, 6, and 9 bud/m, yields were 1.5, 3.5, and 3.4 kg/vine on 1M vine spacing and 4.6, 7.5, and 7.4 kg/vine on 2m spacing. The balance of crop to vegetative growth depended solely on pruning level. Crop to pruning weight ratios were 3.9, 6.6, and 9.2 for the 3, 6, and 9 bud/m2 treatments. Rootstock and vine spacing had no effect on fruit composition at harvest. Maturities depended on pruning level without significant interaction. Soluble solids were adequate up to pruning levels of 6 buds per square meters but fell below 23° Brix at higher bud numbers.

PDF: Rootstock Interaction with Cultural Practices

Rootstock Interactions with Cultural Practices

This project covers three objectives. It evaluates the interaction of rootstock with increased buds retained at pruning at the Oakville Experimental Vineyard, the performance of rootstocks with several in-row spacings under non-irrigated conditions at the Oakville Experimental Vineyard and the interaction of nine rootstocks with potassium application in Merlot with Chalk Hill Vineyards.

The response of cordon trained Cabernet Sauvignon on 110R, 101-14, and 5-C rootstocks to a wide range of pruning levels was evaluated to examine the interaction of rootstock and pruning formula. Rootstock had no effect on the measured components of fruit composition at harvest. Maturities varied in response to pruning level with a significant interaction between pruning and spacing. Closer spacing resulted in a steeper decline in maturity with incremental increases in bud number. This was especially evident for vines planted on 5C. Pruning level influenced components of yield that depend on shoot number: clusters per vine and total yield. It had no independent effect on components that depend on bud fruitfulness: clusters per shoot and cluster size. Significant interactions arose between pruning and rootstock on the number of berries per cluster and final cluster weight. Cluster weights tended to increase with increasing pruning levels on 5-C and decrease with increasing pruning levels on 110R. Berry size was reduced at high bud numbers on 101-14 and 110R.

In 2000, the in-row spacing treatments had yields of 3.22, 4.07 and 4.44 kg m-1, for the 1.0, 1.6 and 2.2 meter spacing, respectively. The differences in yield was attributed to the numbers of berries per cluster with the 1.0, 1.6 and 2.2 m treatments having 120, 130 and 133 berries cluster-1, respectively. There were no differences in berry weight. The four-year average also showed that yield was lower at the 1.0 m spacing than the 1.6 and 2.2 m spacing treatments, 2.49, 3.15 and 3.20 kg m-1, respectively. The lower yield of the 1.0 m spacing was attributed to both smaller berries and fewer berries per cluster. In 2000, there was no effect of rootstock on yield for those vines pruned to equivalent buds per vine. Likewise, the components of yield, berry weight, cluster weight and berries per cluster did not differ. These results are consistent with the cumulative four-year averages.

At the Chalk Hill Merlot site yield in 2000 was equal to the four-year mean at 8.5 kg vine-1. However, when the effect of the potassium fertilizer treatment is taken into account we see a different picture. Yields for vines receiving potassium fertilizer were slightly higher (0.4 kg vine-1). Indeed, yield has been higher for vines receiving potassium fertilizer for all but the first year. In the last two years, 1999 and 2000, the increased yield has been approximately 1.5 kg vine-1. The yield increase has been largely accomplished through an increase in cluster number arising from an increase in shoot number. The vines have been pruned as was appropriate for each vine therefore, the increase in shoot number represents an increase in perceived capacity.

PDF: Rootstock Interactions with Cultural Practices

Rootstock Interactions with Cultural Practices

This project covers three objectives. It evaluates the interaction of rootstock with increased buds retained at pruning at the Oakville Experimental Vineyard, the performance of rootstocks with several in-row spacings under non-irrigated conditions at the Oakville Experimental Vineyard and the interaction of nine rootstocks with potassium application in Merlot with Chalk Hill Vineyards. The response of cordon trained Cabernet Sauvignon on 110R, 101-14, and 5-C rootstocks to a wide range of pruning levels was evaluated to examine the interaction of rootstock and pruning formula. Rootstock had no effect on the measured components of fruit composition at harvest. Maturities varied in response to pruning level with a significant interaction between pruning and spacing. Closer spacing resulted in a steeper decline in maturity with incremental increases in bud number. This was especially evident for vines planted on 5C. Pruning level influenced components of yield that depend on shoot number: clusters per vine and total yield. It had no independent effect on components that depend on bud fruitfulness: clusters per shoot and cluster size. Significant interactions arose between pruning and rootstock on the number of berries per cluster and final cluster weight. Cluster weights tended to increase with increasing pruning levels on 5-C and decrease with increasing pruning levels on 11 OR. Berry size was reduced at high bud numbers on 101-14 and 11 OR. In 2000, the in-row spacing treatments had yields of 3.22, 4.07 and 4.44 kg m”1, for the 1.0, 1.6 and 2.2 meter spacing, respectively. The differences in yield was attributed to the numbers of berries per cluster with the 1.0, 1.6 and 2.2 m treatments having 120, 130 and 133 berries cluster’1, respectively. There were no differences in berry weight. The four-year average also showed that yield was lower at the 1.0 m spacing than the 1.6 and 2.2 m spacing treatments, 2.49, 3.15 and 3.20 kg m”1, respectively. The lower yield of the 1.0 m spacing was attributed to both smaller berries and fewer berries per cluster. In 2000, there was no effect of rootstock on yield for those vines pruned to equivalent buds per vine. Likewise, the components of yield, berry weight, cluster weight and berries per cluster did not differ. These results are consistent with the cumulative four-year averages. At the Chalk Hill Merlot site yield in 2000 was equal to the four-year mean at 8.5 kg vine”1. However, when the effect of the potassium fertilizer treatment is taken into account we see a different picture. Yields for vines receiving potassium fertilizer were slightly higher (0.4 kg vine’1). Indeed, yield has been higher for vines receiving potassium fertilizer for all but the first year. In the last two years, 1999 and 2000, the increased yield has been approximately 1.5 kg vine”1. The yield increase has been largely accomplished through an increase in cluster number arising from an increase in shoot number. The vines have been pruned as was appropriate for each vine therefore, the increase in shoot number represents an increase in perceived capacity.

Rootstock Interaction with Cultural Practices

Cabernet Sauvignon grown on four rootstocks (3309, 5C, 110R, and 039-16) were balance pruned to four different pruning formulae and examined for effects on yield, vegetative growth, and fruit maturity. Optimal pruning formula for each stock was determined for four different growth parameters. Maturation was dependent on crop load. Higher pruning formulas delayed maturity both directly and through influences on crop. Soluble solids at harvest were 24.1, 23.7, 23.5, and 23.2 °Brix for the 5, 7.5, 10, and 12.5 bud/lb treatments. Rootstock appeared to have a direct influence; at average crop loads, fruit ripened earlier if planted on 3309 and later if planted on 039-16. Low crops mitigated the rootstock effect on maturity in some years. Vines produced lower yields on 0329-16 than on other rootstocks: 5.8, 7.0, 7.9, and 8.6 kg/vine for 039-16, 3309, 5C, and 110R respectively. The responsible components were fewer clusters per shoot and fewer shoots per vine at any given formula for that rootstock. Pruning formula affected all components of yield except berry weight. Increases in buds retained at successively higher formulas resulted in more shoots and more clusters per vine but was offset by reduced bud viability and reduced clusters per shoot. The net effect was an increase in yield from 6.2 to 6.9, 7.6, and 8.5 kg/vine at the 5, 7.5, 10, and 12.5 bud treatments. Larger initial vine sizes increased yield through number of shoots per vine. Vines produced shorter shoots on 039-16 and 5C than on 3309 or 110R. Vines on 039-16 also carried fewer shoots resulting in large differences in total leaf area per vine. Total average leaf areas were 7.0, 8.2, 9.1, and 10.1 m2/vine for 039-16, 5C, 3309, and 110R. Increased pruning formulas increased shoot number but proportionately decreased shoot length and bud viability. Average total leaf area per vine therefore did not differ by pruning formula. Larger initial vine size increased total leaf area/vine through increased shoot number but did not affect shoot elongation. Pruning formula, not total shoots per vine, regulated vigor. Two measures of vigor and two measures of crop/vegetative balance were examined as criteria in assigning an optimal pruning formula to each rootstock. The formulas required to produce uniform shoot vigor were 8.3 buds/lb for 3309 and 110R, 7.4 for 5C, and 7.1 for 039-16. Formulas necessary to produce uniform crop/vegetative partitioning averaged 9.6 buds/lb on 3309, 8.4 on 039-16, 8.0 on 110R, and 6.2 on5C.

Development of New Rootstocks for use in Napa Valley Fanleaf Sites

Major Objectives

  • Develop screen for X index resistance.
  • Screen rupestris x rotundifolia, champinii x rotundifolia, other rotundifolia hybrids in a lab or greenhouse assay to choose candidates for field testing.
  • Continue searching for other forms of resistance to X. index and GFLV for use in fanleaf resistant rootstock breeding.
  • Map X. index resistance with DNA markers (RAPD and AFLP) to locate genes responsible for resistance. Study new seedling populations (produced during the 96 season) to determine the genetic and mechanistic controls of fanleaf resistance.
  • Field test X. index resistant rupestris x rotundifolia selections for their resistance to fanleaf.

Funding for this project is primarily directed at supporting a rootstock trial with BV Winery and Walsh Vineyard Management. Development of fanleaf resistant rootstocks is part of a larger project funded by the California Grape Rootstock Improvement Commission. The plot at BV is now well established and being trained up the stake and onto the cordon wires. We sampled 60 of the susceptible control St. George vines at this site in June to see how evenly X. index was spread through the field. All 60 samples had clear feeding damage and had from 20 to 400 X. index per liter of soil. None of the foliar samples were GFLV positive yet, but it generally takes at least 2 years to detect GFLV once the vines are inoculated. This result gives us confidence that the site is uniformly and evenly infested with nematodes. We have found additional sources of X. index resistance in V. cinerea, V. rufotomentosa and M. rotundifolia. These will be used in future crosses. A second generation of rupestris ~K rotundifolia (Rup X Rot) seedlings have been produced from crosses of resistant X susceptible seedlings. These should have excellent viticultural characteristics (less rotundifolia like) and maintain very high X. index resistance. We have also mapped the resistance trait in this population with AFLP DNA analysis and are establishing where resistance resides.

Field Evaluation of Winegrape Rootstocks

Data from 1997 continue the trends of previous years. Considerable differences can be seen in the performance of rootstocks. These differences take the form of yield and pruning weights and their various components, as well as juice maturity indices and potassium content. Differences among rootstocks are not the same from plot to plot. In fact, some rootstocks perform radically differently. Therefore because broad generalizations are not possible, a close look at the entire report is necessary and this executive summary will be brief The differences among sites may be due to several possibilities including: 1) a rootstock by site interaction, in which the soil depth, texture, chemistry and water-holding capacity influence the performance of a rootstock; 2) a rootstock by scion variety interaction in which a scion’s vigor or physiology exerts an influence on the performance of a rootstock (these interactions have been reported but their cause is not well understood); and 3) a rootstock by cultural practice interaction, in which the cultural conditions imposed by the cooperator has an impact on some rootstocks more than others, including trellis, irrigation, fertilization and cropping patterns. To completely understand the data in this report, further interactive studies will be needed (see “Interaction of Rootstocks with Cultural Practices” funded by the American Vineyard Foundation.)

Rootstock Interaction with Cultural Practices

This report contains the results of three studies centered on the question of how rootstocks may interact with cultural practices. Because of limited space, this summary will focus on the results of a) how rootstock performance differs in response to crop load and b) how rootstocks respond to in-row spacing under dry-farmed conditions. In the first study, beginning in 1995, Cabernet Sauvignon grown on four rootstocks (3309, 5C, 110R, and 039-16) were balance pruned to four different pruning formulae (5, 7.5, 10, and 12.5 buds/lb of 1- and 2-year-old wood). In the third year of study, the vines have begun to attain a stable partitioning of crop and vegetative growth. The rootstock influenced rate of maturation. Vines on 3309 had the highest average soluble solids at harvest followed by 110R, 039-16, and 5C (24.6, 23.7, 23.5, and 23.3 °Brix respectively). Higher pruning formulas delayed maturity both directly and through influences on crop load. While still significant, differences in maturation were minimized by rootstock dependent cropping patterns and increased by pruning formula effects on crop. Vines on 039-16 produced lower yields than those on other rootstocks; 6.2, 7.5, 8.5, and 8.5 kg/vine for 039-16, 3309, 5C, and 110R, resp. Pruning formula affected all components of yield except berry weight. The increase in buds retained at each higher formulas resulted in more shoots and more clusters per vine. The net effect was a 30{aed9a53339cdfc54d53cc0c4af03c96668ab007d9c364a7466e3349a91bf0a23} increase in crop from the 5 to the 12.5 bud/lb treatment. Leaf area per gram crop decreased with increasing pruning formula from 13.8 to 8.2 cm2 / gm but did not vary by rootstock. In the second study, three putative rootstocks (11 OR, 1103P and 140Ru) were compared with a putative drought-sensitive rootstock (5C) at three in-row spacings (1.0, 1.6, and 2.2 m) to test whether, under non-irrigated conditions, rootstocks performed differently when increasing soil volumes were available. Shoot spacing was held constant at about 12 shoots/m cordon. In 1997 regardless of the vine spacing, 5C showed less growth per m cordon as a result of shorter shoots. 5C also had less yield per meter cordon, at the wider spacings, as a result of fewer clusters/m (despite equal shoots/m) and fewer berries/cluster. Vines at the 1.0 m spacing ripened before the wider spacings and 5C at all spacings ripened first. Water status measurements showed that 5C had among the highest values for water potential (least drought), although no vines showed less than -1.4 MPa. Investigations in 1998 will concentrate on whether 5C’s water status may be due to lower leaf area/vine than the more vigorous “drought-resistant” rootstocks.

Field Evaluation of Winegrape Rootstocks

Data from 1996 continue the trends of previous years. Considerable differences can be seen in the performance of rootstocks. These differences take the form of yield and pruning weights and their various components, as well as juice maturity indices and potassium content. Differences among rootstocks are not the same from plot to plot. In fact, some rootstocks perform radically differently. Therefore because broad generalizations are not possible, a close look at the entire report will necessary and this executive summary will be brief. The differences among sites may be due to several possibilities, including: 1) a rootstock by site interaction, in which the soil depth, texture, chemistry and water-holding capacity influence the performance of a rootstock; 2) a rootstock by scion variety interaction in which a scion’s vigor or physiology exerts an influence on the performance of a rootstock (these interactions have been reported but their cause is not well understood); and 3) a rootstock by cultural practice interaction, in which the cultural conditions imposed by the cooperator has an impact on some rootstocks more than others; these might include trellis, irrigation, fertilization and cropping patterns. To completely understand the data in this report, further interactive studies will be needed (see, “Interaction of Rootstocks with Cultural Practices” funded by the American Vineyard Foundation.)