Viticulture Data Journal :
Research Article
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Corresponding author: Thayne Montague (thayne.montague@ttu.edu)
Academic editor: Denis Rusjan
Received: 05 Nov 2020 | Accepted: 18 Dec 2020 | Published: 21 Dec 2020
© 2020 Thayne Montague, Emily Graff, Suraj Kar
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Montague T, Graff E, Kar S (2020) Secondary Bud Gas Exchange, Growth, and Fruitfulness of Vitis vinifera L. cultivars, ‘Grenache’ and ‘Cabernet Sauvignon’ Grown on the Texas High Plains. Viticulture Data Journal 2: e60430. https://doi.org/10.3897/vdj.2.e60430
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In 2017, the grape and wine industry had an overall economic impact of $13.1 billion within the state of Texas. The majority of grapes grown in Texas are produced within the Texas High Plains American Viticultural Area (AVA). However, vineyards within the Texas High Plains AVA are subject to late spring frosts which can potentially diminish fruit quality, and reduce crop production. To assist in planning and production efforts, Texas High Plains AVA grape growers require information regarding vine secondary bud growth and fruitfulness. Therefore, the objectives of this experiment were to compare the growth and fruitfulness of shoots grown from primary and secondary buds of Vitis vinifera L. ‘Grenache’ and ‘Cabernet Sauvignon’ vines grafted to 110R rootstocks. Vines were planted in an experimental vineyard in 2008. Each year over two consecutive growing seasons (2016 – 2017) vines were exposed to the following treatments: primary bud growth intact, and following bud break allowing primary bud shoot growth to reach 15.0 cm in length then removing primary bud shoots (forcing growth from secondary buds). Gas exchange, growth, fruitfulness, and fruit total soluble solid data were collected each year. Collected data followed similar trends each growing season. Hence, data from each growing season were pooled. Gas exchange data indicate leaves from primary shoots had lower photosynthetic rates, and stomatal conductance when compared to leaves grown on secondary shoots. In addition, ‘Grenache’ leaves had greater gas exchange when compared to ‘Cabernet Sauvignon’ leaves. Pruning weights, vine yield, cluster mass, and total soluble solids were greater for shoots grown from primary buds. ‘Cabernet Sauvignon’ vines had greater pruning weights, but ‘Grenache’ vines had greater crop load (Ravaz Index) and cluster mass. Yield and total soluble solids did not differ between grape cultivars, but the number of clusters from each vine, and berry mass varied with cultivar and bud treatment. In the late spring frost-prone Texas High Plains AVA, cultivar selection continues to be a critical factor for vineyard success. Results indicate decreased yields from all vines with shoot growth only from secondary buds. However, even though ‘Grenache’ and ‘Cabernet Sauvignon’ vines responded differently to bud treatments (‘Cabernet Sauvignon’ vines generally produced a greater number of smaller clusters when compared to ‘Grenache’ vines), for each cultivar overall yield was similar across all bud treatments. Therefore, Texas High Plains AVA and other grape producers now have additional information that may assist them when making critical vineyard management choices.
Compound bud, primary bud, spring frost injury, gas exchange
Although grapes have been grown in Texas since the mid-1600's, the modern commercial viticulture industry is relatively young (
The vast majority of grape bearing ha in Texas (60%), and grape production (73%) are located in the Texas High Plains AVA (
Despite Texas High Plains AVA vineyards producing the majority of wine grapes within the state (
Incidence and severity of damage due to late spring frost depends on plant susceptibility factors, minimum air temperature achieved, and length of time at or below the critical temperature which can damage new growth (
During the growing season, Vitis species develop a compound bud composed of primary, secondary, and tertiary buds in each leaf axil (node) (
Because frost damaged primary shoots are generally replaced by shoots produced from quiescent, secondary buds (
Experiments were conducted during the 2016 and 2017 growing seasons at the Texas A&M AgriLife Research and Extension Center, Lubbock, TX (
To simulate late spring frost damage to new shoots (secondary shoot treatment (SST)), primary shoot growth was allowed to grow following primary bud break until new shoots reached approximately 15.0 cm in length. For two consecutive growing seasons, the initial 15.0 cm of growth from primary buds was removed by pruning (shoot removal pruning was completed 9 May in 2016, and 25 Apr. in 2017), and secondary buds were induced to break (
During three cloudless days in 2016 (6 May, 13 Jun., 25 Jul.), and 2017 (6 Jun., 20 Jul., and 7 Aug.), mid-day (solar noon ± 1 hr.) leaf stomatal conductance (gs), and net photosynthetic rate (PN) were measured using two LI-6400 XT machines (Li-Cor Biosciences Inc., Lincoln, NE). Gas-exchange data collected 6 May 2016 was taken prior to instigating SST. Intrinsic water use efficiency (WUEI) was calculated as the ratio of PN and gs (
Fruit harvest maturity was determined by berry juice assays of total soluble solids (°Brix). To estimate Brix value, 50 berries from each vine were sampled from shoulders, middle, and tip of random clusters (
Yearly (2016 and 2017) precipitation totals (cm), growing season daily minimum and maximum air temperature (ºC), and mean maximum and mean minimum air temperature (ºC) were also recorded using an onsite weather station (Campbell Scientific, Logan, UT) (Table
Annual cumulative growing degree days (GDD), precipitation, minimum temperature, mean minimum temperature, and mean maximum temperature during the 2016 and 2017 growing seasons. In addition secondary shoot pruning date and harvest date for Vitis vinifera ‘Grenache’ and ‘Cabernet sauvignon’ vines grafted to 110R rootstocks growing on the same location are shown.
Year |
Cumulative GDDz |
Precipitation (cm) |
Temperature (ºC)y |
Date |
||||
Minimum |
Maximum |
Mean minimum |
Mean maximum |
SSTx pruning |
Harvest |
|||
2016 |
2,779 |
29.9 |
0.1 |
42.8 |
15.6 |
30.3 |
9 May |
28 Aug. |
2017 |
2,644 |
46.7 |
-2.2 |
44.4 |
14.9 |
29.7 |
25 Apr. |
14 Sept. |
zGrowing degree days (10.0 ºC); yClimate date from 1 Apr. to 31 Oct; xSecondary shoot treatment.
Growing degree day (GDD) heat unit accumulation was calculated from 1 Apr. to 31 Oct. for each experiment year using the equation (
\(GDD=∑{(Tmax + Tmin)/2- Tbase}\)
Where, Tmax and Tmin are mean daily maximum and minimum temperatures (ºC) respectively, and Tbase is the base temperature for grapes (10 °C) (
Daily gas-exchange, pruning, yield, and fruit data means were exposed to analysis of variance using the General Linear Models procedure appropriate for a randomized complete block design (SAS version 9.4, SAS Institute, Cary, NC). For each growing season, gas-exchange daily means indicated similar trends (no interaction found for data from separate years). Therefore, daily gas-exchange data from within each growing season were pooled. However, gas exchange data from 6 May, 2016 (prior to instigating SST) was not pooled with other gas exchange dates. In addition, pruning weight, yield, and fruit data means followed similar trends for each growing season (no interaction found for data from separate years). Therefore pruning weight, yield, and fruit data means from 2016 and 2017 were also pooled for statistical analysis. If mean differences were detected, least square means were separated by Tukey-Kramer’s procedure (a = 0.05). Pooled least square means for gas-exchange parameters (PN, gs, and WUEI) were plotted by bud treatment, and grape cultivar. Figures was created using Sigma Plot software (version 14.0, Systat Software, San Jose, CA).
Historical climate data (2000 – 2019) for Lubbock and Terry counties indicate numerous late spring frosts occurred in each location (Fig.
Total number of days (1 March - 30 April, 2000 - 2019) air temperature was at, or below -2.0 °C for two rural locations within the Texas High Plains AVA (Lubbock County, TX (A), and Terry County, TX (B)). In addition, mean, daily low temperature, and cumulative days at, or below -2.0 °C for each location.
Growing degree days data during each experiment growing season (1 Apr. – 31 Oct.) indicate the 2016 growing season was somewhat warmer (5% greater number of GDD) when compared to the 2017 growing season (Table
Initial (pre-SST) gas-exchange measurements from 2016 indicate no differences between SST and PST leaf gas-exchange data for PN, gs, or WUEI (data not shown). However, initial data from 2016 show leaf PN and gs were greater for ‘Cabernet Sauvignon’ vines compared to leaf PN and gs for ‘Grenache’ vines. In addition, the initial 2016 mid-day leaf WUEI was greater for ‘Grenache’ vines compared to mid-day WUEI of leaves from ‘Cabernet Sauvignon’ vines (data not shown). Pre SST mid-day leaf gas exchange data for the 2017 growing season was not available for analysis. Pooled (2016 and 2017) leaf gas exchange data indicated leaf PN and gs were greater (8% and 15%, respectively) for SST vines, while WUEI did not differ between leaves from SST and PST vines (Fig.
Effects of primary or secondary bud shoot growth, and cultivar on mid-day leaf photosynthetic rate (A, B), stomatal conductance (C, D), and intrinsic water use efficiency (E, F) for field grown Vitis vinifera ‘Grenache’ and ‘Cabernet Sauvignon’ vines grafted to 110R rootstocks. Each bar represents least square mean of approximately 180 measurements (2016 and 2017 data was pooled). Letters above each bar represent differences between bud type, or cultivar for each date. If a letter is not present, means are not significantly different. (Tukey-Kramer test, P ≤ 0.05). Error bars represent SE for each bud type or cultivar.
Pruning weight results indicate greater shoot weight for shoots grown from PST buds, and ‘Cabernet Sauvignon’ vines (Table
Effect of primary or secondary bud shoot growth on pruning weight, yield, and fruit quality characteristics for Vitis vinifera ‘Cabernet sauvignon’ and ‘Grenache’ vines grown on 110R rootstock at the Texas AgriLife vineyard in Lubbock, TX. Data was pooled from 2016 and 2017 growing seasons.
Pruning weight (g) |
Yield (g vine-1) |
Ravaz index |
Cluster mass (g) |
Cluster vine-1 |
Berry mass (g) |
TSSz (ºBrix) |
|
Treatment |
|||||||
Primary buds |
344.1 ay |
597.5 a |
3.28 |
27.8 a |
- |
- |
24.1 a |
Secondary buds |
226.2 b |
287.6 b |
2.18 |
20.6 b |
- |
- |
21.6 b |
Cultivar |
|||||||
Cabernet sauvignon |
357.3 a |
445.6 |
1.53 b |
15.9 b |
- |
- |
21.6 |
Grenache |
164.2 b |
439.4 |
3.93 a |
32.5 a |
- |
- |
23.9 |
Treatment × Cultivar |
|||||||
Cabernet sauvignon × primary |
- |
- |
- |
- |
33.5 a |
0.64 c |
- |
Grenache × primary |
- |
- |
- |
- |
15.5 c |
1.08 a |
- |
Cabernet sauvignon × secondary |
- |
- |
- |
- |
20.1 b |
0.39 d |
- |
Grenache × secondary |
- |
- |
- |
- |
10.3 d |
0.73 b |
- |
Significance |
P > F |
||||||
Treatment |
0.0011 |
0.0072 |
0.0518 |
0.0001 |
0.0001 |
0.0001 |
0.0307 |
Cultivar |
0.0001 |
0.9552 |
0.0001 |
0.0001 |
0.0001 |
0.0001 |
0.0543 |
Treatment × Cultivar |
0.1476 |
0.6010 |
0.2124 |
0.0021 |
0.0438 |
0.0241 |
0.3291 |
zTotal soluble solids; yLeast square means within columns followed by different letter are different by Tukey-Kramer test (P ≤ 0.05).
Each experiment year between 1 Apr. and 31 Oct. minimum air temperature dropped to near freezing, or below on two occasions (Table
Because post-budbreak, late spring frosts are considered common for Texas High Plains AVA vineyards, producers within the Texas High Plains AVA have implemented numerous mitigation strategies to reduce crop loss due to late spring frosts (
Under non-water stressed growing conditions, several authors directly compared leaf PN and gs of ‘Grenache’ and ‘Cabernet Sauvignon’ vines.
A number of authors report the sensitivity of grape foliage, yield, or fruit quality to late spring frosts and damage to primary buds (
During the initial measurement date of the 2016 growing season (6 May), which was prior to SST pruning, mean WUEI was lower for ‘Cabernet Sauvignon’ leaves when compared to ‘Grenache’ leaves (data not shown). However, post SST pruning WUEI was not different between cultivars (Fig.
Similar to PN and gs data, this appears to be the first study comparing WUEI between leaves grown from grapevine primary and secondary shoots. However, unlike leaf PN and gs means, WUEI differences between SST and PST vines were not found (Fig.
It is a commonly understood pruning weight data from shoots grown from Vitis spp. secondary buds are less when compared to pruning weight data of shoots grown from vine primary buds (
In addition to lower pruning weights, mean vine yield was less for shoots from SST buds when compared to yield from shoots of PST buds (Table
The ratio of yield weight to pruning weight (Ravaz Index) is often used as an expression of crop load to indicate vine balance (
Based on crop load data, vines in this study were under cropped (Table
For all vines, overall yield was closely related to cluster mass (PST and ‘Grenache’ vines produced clusters with greater mass), the number of clusters produced from each vine (‘Cabernet Sauvignon’ PST vines produced the greatest number of clusters, while ‘Grenache’ SST vines produced the least number of clusters), and berry mass (largest berries were produced by ‘Grenache’ PST vines, and smallest berries were produced by ‘Cabernet Sauvignon’ SST vines) (Table
Although WUEI did not differ between SST and PST leaves, or ‘Grenache’ and ‘Cabernet Sauvignon’ leaves (Fig.
Fruit quality (TSS) differed for berries from PST and SST shoots, and there was a trend for ‘Grenache’ berries to have greater TSS when compared to ‘Cabernet Sauvignon’ berries (Table
Vineyards within the Texas High Plains AVA are subjected to yield losses and management challenges associated with late spring frosts. In response to selective pruning, gas-exchange, growth, and fruitfulness of shoots produced by secondary buds of ‘Grenache’ and ‘Cabernet Sauvignon’ grapevines were compared to shoots grown from primary buds of the same cultivars. This report concurs with previous work which indicates yield, and fruit quality generally suffers when wine grape primary buds are damaged due to late spring frosts. However, it appears this report is the first to conclude that when compared to leaves produced from primary shoots, gas-exchange is greater for leaves produced from secondary shoots. In addition, although, vine vigor, bud fertility and yield data were lower than commonly found within Texas High Plains AVA vineyards, trends for PST, SST, ‘Grenache’, and ‘Cabernet Sauvignon’ yield indicate even though ‘Grenache’ and ‘Cabernet Sauvignon’ vines had similar yields across PST and SST treatments, PST, SST, and cultivar had an interactive effect on clusters produced from each vine and individual berry mass. Data indicate ‘Grenache’ (smaller fruit and greater berry mass), and ‘Cabernet Sauvignon’ (larger fruit and lower berry mass) vines responded differently to PST and SST treatments. To better understand grapevine cultivar interactions with late spring frost damage within vineyards on the Texas High Plains AVA, possible future research may include post late spring frost vineyard survival and fertility surveys of commonly grown grape cultivars within the Texas High Plains AVA. Vineyard management before and following late spring frosts is critical for current, and future vineyard productivity. Viticulturists within the Texas High Plains AVA now have additional information that may assist them when making these crucial vineyard management decisions.
We thank the Department of Plant and Soil Science at Texas Tech University and Texas AgriLife Research and Extension, State of Texas Viticulture and Enology Research, Education, and Engagement Funding for supporting this research.
Texas Tech University, Lubbock, TX
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