Method for delaying maturity of wine grapes

Abstract

The invention relates to the technical field of grape cultivation, in particular to a method for delaying maturity of wine grapes, which comprises the following steps: pruning the grapes in the grape coloring completion period; the pruning comprises the step of removing 1 / 4-1 / 3 of young sprouts at the tops of grape leaf curtains. Experiments show that the method can effectively delay the ripening process of the wine grapes, can delay the harvesting time of the grapes by 6-11 days, and does not affect the yield of a vineyard and the quality of the wine grapes. The method is simple and convenient to operate, is verified by repeated field tests for many years, has relatively high reproducibility, can be used for solving the problem of too fast maturity in western producing areas in China, and is an effective method for delaying grape maturity.

Description

Technical Field

[0001] The invention relates to the technical field of grape cultivation, and in particular to a method for delaying the maturation of wine grapes. Background Art

[0002] Grapes (Vitis vinifera L.) are sensitive to changes in climatic conditions. In the past few decades, the wine industry has been profoundly affected by global warming (Gutiérrez-Gamboa et al., 2021, Current viticultural techniques to mitigate the effects of global warming on grape and wine quality: A comprehensive review, Food Res. Int., 139 (2021), 109946,

[0003] 10.1016 / j.foodres.2020.109946). In the past fifty years, the average temperature in western China has risen by about 2°C, and the average temperature in the growing season has increased by about 1.6°C (Lu et al., 2022, Distalleaf removal made balanced source-sink vines, delayed ripening, and increased flavonol composition in Cabernet Sauvignon grapes and wines in the semi-arid Xinjiang Food Chem., 366 (2022), 130582, 10.1016 / j.foodchem.2021.130582). In cool production areas, climate warming allows grapes to reach ideal maturity, while in hot production areas, climate warming leads to a series of problems. The disconnect between the sugar content and flavor compounds in grapes poses a challenge to winemakers. Therefore, finding suitable low-cost and labor-intensive technologies, especially the development of delayed ripening technologies in grape cultivation, is the focus of winemakers and researchers.

[0004] The climate in the wine grape producing areas in western China is relatively dry, and the development of grapes is easily subjected to heat waves and strong light stress, so grape growers usually choose thicker leaf curtains to protect the grapes from sunburn, which results in a higher leaf-to-fruit ratio in the grape vines. This results in an accelerated ripening process and excessive sugar accumulation during the ripening process of the grapes. The grapes mature in higher temperatures, resulting in the loss of the typical flavor of the grapes. At present, there is still a lack of a simple and effective method that can be applied to the western production areas of China to delay the ripening of grapes. In view of the increasing adverse effects of global warming on the western production areas of China, it is necessary to establish a cultivation technology that delays the phenological period of grapes and balances the source-sink relationship of grape vines. Summary of the invention

[0005] In view of this, the present invention provides a method for delaying the ripening of wine grapes. The method can delay the grape harvest period by 6 to 11 days without affecting the yield of the vineyard and the quality of the wine grapes. Moreover, the method is easy to operate and has high reproducibility.

[0006] A method for delaying the growth of grapes, comprising: pruning the grapes during the grape color change completion period; the pruning comprises: removing 1 / 4 to 1 / 3 of the new shoots on the top of the grape leaf curtain.

[0007] In the present invention, the pruning period is specifically: the period from 0 to 2 days after the grape berries are all colored and the fruit sugar content is 15.5 to 16.5 ° Brix. The day when the grape berries are all colored is day 0, and the days thereafter are recorded as day 1 and day 2. In some specific embodiments, the sugar content is measured using an Atago sugar meter, and the result is measured in ° Brix.

[0008] In the present invention, the new shoots at the top of the grape leaf curtain are removed, and the height of the leaf curtain after pruning is 1.2 to 1.35 m, specifically 1.2 m, 1.25, 1.3 m, 1.35 m or any value between the above two values.

[0009] In the present invention, the area of ​​the grape leaf curtain after pruning after the new shoots on the top of the leaf curtain are removed is 30% to 40% of the area before pruning, and can be specifically 30%, 32%, 34%, 36%, 38%, or 40%.

[0010] In the present invention, the step of measuring and calculating the leaf curtain area is also included 1 to 3 days before pruning. In some embodiments, the step of measuring and calculating the leaf curtain area includes: randomly selecting ten new shoots for each repetition to measure the leaf area, and repeating it three times in total. Further, the method for measuring the leaf area is: measuring the leaf area in situ with a Yaxin-1242 leaf area meter on the leaves of the new shoots.

[0011] In the method for delaying the harvesting of grapes of the present invention, the grapes include wine grapes. Among them, the wine grapes include Cabernet Sauvignon, Marselan, Merlot or Syrah. In some specific embodiments, the grapes are wine grapes. The present invention takes Cabernet Sauvignon as an example to verify that the method of the present invention can delay the grape harvesting period by 6 to 11 days without affecting the yield and winemaking quality of Cabernet Sauvignon.

[0012] In the present invention, the method further comprises: timely tying the new shoots with the tops removed to the vineyard shelf. In some embodiments, the tying position of the new shoots is 1.0 to 1.1 m of the leaf curtain height.

[0013] In the present invention, the method further comprises the step of monitoring the maturity of berries during the phenological period.

[0014] In some embodiments, the monitoring of berry maturity during the phenological period includes: random berry sampling every 10 days after topping, testing the sugar content after crushing and extracting juice, and recording the time when the berries complete color change and are harvested.

[0015] In some specific embodiments, the method for delaying grape growth of the present invention comprises the following steps:

[0016] (1) Time for heavy topping of new shoots: When the wine grapes have completed their color change, leaf canopy management should be performed, specifically when all the grape berries are colored;

[0017] (2) Determination and calculation of leaf area: Leaf area was measured 1 to 3 days before leaf curtain treatment. Ten new shoots were randomly selected for leaf area measurement in each repetition, with a total of three repetitions;

[0018] (3) Method for heavy topping of new shoots: Measure the height of the leaf curtain and new shoots. Generally, the leaf curtain height of vineyards in western production areas is about 1.8m, and the length of the new shoots to be cut is controlled to be 0.45m. Use gardening pruning shears to cut the new shoots, and measure the remaining leaf area after cutting to ensure that the cut leaf area is 30% to 40% of the total leaf area;

[0019] (4) Management of new shoots after topping: After topping, new shoots should be tied to the vineyard racks in time to ensure the neatness of the leaf curtain and prevent the loose leaf curtain from causing excessive exposure of the fruit bunches;

[0020] (5) Monitoring of berry maturity during the phenological period: Random berry sampling was performed every 10 days after topping, and the sugar content was tested after crushing the juice. The time when the berries changed color and were harvested was recorded.

[0021] The present invention provides a method for delaying the ripening of wine grapes, the method comprising: pruning the grapes during the grape color change completion period; the pruning comprises: removing 1 / 4 to 1 / 3 of the new shoots at the top of the grape leaf curtain. Experiments show that the method can effectively delay the ripening process of wine grapes, can delay the grape harvest period by 6 to 11 days, and does not affect the yield of the vineyard and the quality of the wine grapes. The method is simple to operate, and has been verified by repeated field tests for many years. The method has high reproducibility, can be used to solve the problem of too fast ripening in the western production areas of my country, and is an effective method for delaying the ripening of grapes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of heavy topping of new shoots;

[0023] Figure 2 This is the effect of severe new shoot topping on soluble solids (TSS), titratable acid (TiA), pH and 100 berries weight of Cabernet Sauvignon grapes in Example 1. DETAILED DESCRIPTION

[0024] The present invention provides a method for delaying the ripening of wine grapes. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve the desired effect. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the method and application of this article without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0025] The test materials used in the present invention are all common commercial products and can be purchased in the market.

[0026] The present invention will be further described below in conjunction with embodiments:

[0027] Example 1 Effect of heavy topping of new shoots on the ripening process of Cabernet Sauvignon grapes in Manasi production area

[0028] This example was conducted in a commercial vineyard in Manas, Xinjiang, northwest China (44°24′N-86°26′E, 522m above sea level), which has a temperate continental semi-arid climate. The test material was Cabernet Sauvignon grapes, self-rooted seedlings, planted in 2011, using improved VSP shaping, with a plant spacing of 1m×3m. The vineyard row direction was northeast-southwest (52°), with 18-22 nodes and 27-33 fruit clusters per extended meter. The grapevines were furrow irrigated during the budding stage, flowering stage, pea-sized stage, color change stage and harvest stage (about three weeks before harvest), with an irrigation volume of 750m 3 ·ha -1Three adjacent rows in the vineyard were selected for this experiment. From 2018 to 2020, 45 grape vines with uniform growth were selected from each row and subjected to severe shoot topping treatment, recorded as SST.

[0029] (1) Determination of leaf area before treatment: Before harvest, 10 grape vines were randomly selected for each treatment, and 3 new shoots were randomly selected from each grape vine. The leaf areas of the main and secondary shoots of the new shoots were measured using a portable Yaxin-1242 leaf area meter. Ten new shoots were measured for each replicate.

[0030] (2) Severe pruning of new shoots: A total of three years of experiments were conducted: from 2018 to 2020, all branches and leaves were pruned from the top of the canopy to 1.35 meters above the ground at the end of the grape color change period (August 8, TSS ≈ 16° Brix) (see Figure 1 ), which means that 30% to 40% of the new shoots and leaves of the entire crown are completely removed, and the same batch of trees are treated every year.

[0031] (3) Determination of tree growth potential: At harvest, the weight of 10 ears of fruit was measured for each replicate to estimate the yield. During winter pruning, the amount of pruning of 10 trees was measured for each replicate, the length of the new shoot and the diameter of the third node from the base were measured, and the load was calculated by yield / pruning amount. The soluble sugar and starch content of the third node of the new shoot was measured using the anthrone colorimetric method.

[0032] (4) Determination of grape components: 100 berries were weighed using an electronic balance (accuracy 0.01 g). The soluble solids content was determined using a handheld sugar meter (PAL-1, Atago, Japan), and the pH value was determined using a pH meter. The sugar accumulation rate (mg / berry / d) was calculated based on the soluble solids content and berry mass of the berries. The titratable acid of the juice was titrated with a NaOH standard solution, and the result was expressed as tartaric acid (g / L). The flavonoids in grapes were determined using an Agilent 1200 series equipped with a 6410 triple quadrupole mass spectrometer (QqQ). The chromatographic column was Poroshell120EC-C 18, the column temperature was 55°C, the injection volume was 5 μL, the detection wavelength was 525 nm, and the flow rate was 0.4 mL / min. Mobile phase A was 0.1% (v / v) formic acid in water, and mobile phase B was 50 / 50 (v / v) methanol-acetonitrile solution containing 0.1% (v / v) formic acid. The elution program was as follows: 10% to 100% phase B for 15 min, followed by a 5 min post-run program; the acquisition parameters of the ion trap mass spectrometer were an electrospray ion source, positive ion mode, an ion scan range of 100 to 1500 m / z, a nebulizer pressure of 35 psi, a dryer flow rate of 12 L / h, and a drying gas temperature of 350 ° C. The aroma substances in grapes were determined using an Agilent 6890 series gas-mass spectrometer. The carrier gas was high-purity helium with a flow rate of 1 mL / min. The heating program was as follows: 50 ° C for 1 min, then heated to 220 ° C at 3 ° C / min, and finally held for 5 min. The other conditions are as follows: the injection port temperature is 250℃, the detection of grape juice adopts the non-divided mode, the ionization method is electron ionization (EI) source, the ionization energy is 70ev, the ion source temperature is 230℃, the mass spectrometer interface temperature is 280℃, and the mass scanning range is 30~350u.

[0033] (4) Results: The effects of heavy topping of new shoots on the growth and harvest period of grapevines in three consecutive years are shown in Table 1. Heavy topping of new shoots significantly affected tree growth. The pruning treatment significantly reduced the leaf area, leaf-to-fruit ratio and average shoot length of new shoots, main shoots and secondary shoots. Among them, the proportion of total leaf area reduction was 36%, and the proportion of main shoot leaf area reduction was 34-48%. Heavy topping of new shoots had no significant effect on yield, which was also reflected in the number of berries and bunch weight. For grapevine nutrient storage, heavy topping of new shoots in 2019 significantly reduced the soluble sugar content in the branches (p<0.05). There was no significant difference in starch content. Heavy topping of new shoots delayed the harvest period of grapes by 6-11 days.

[0034] Table 1 Effects of heavy shoot topping on grapevine growth and harvest period in three consecutive years

[0035]

[0036]

[0037] Note: * indicates the difference reached the significant level (p<0.05).

[0038] Effects of heavy topping of new shoots on berry composition of Cabernet Sauvignon grape Figure 2 And as shown in Table 2.

[0039] The results showed that the heavy topping of new shoots significantly inhibited the accumulation rate of sugar, which decreased by 0.6 mg / berry / d. The effects on titratable acid, pH and fruit weight were small. Further analysis of secondary metabolites in berries showed that the heavy topping of new shoots did not affect the flavonoids and aroma compounds in the berries.

[0040] Table 2 Effects of heavy topping of new shoots on the main flavor substances in grape berries

[0041] index C SST Significance (t-test) Anthocyanin (mg / kg fresh weight) 1085.72±63.84 1027.98±8.85 >0.05 Flavonols (mg / kg fresh weight) 75.72±14.06 98.30±14.67 >0.05 Flavanols (mg / kg fresh weight) 521.56±302.73 5241.58±92.27 >0.05 C6 / C9 substances (μg / kg fresh weight) 3,875.72±638.07 3,988.98±531.22 >0.05 Aromatic substances (μg / kg fresh weight) 80.68±3.66 82.10±1.94 >0.05 Alcohols (μg / kg fresh weight) 22.19±1.24 21.12±1.10 >0.05 Norisoprene (μg / kg fresh weight) 34.24±3.33 39.45±2.03 >0.05 Aldehydes / ketones (μg / kg fresh weight) 56.74±8.39 49.08±3.47 >0.05 Terpenes (μg / kg fresh weight) 23.60±0.43 24.08±1.01 >0.05 Acids (μg / kg fresh weight) 16.43±3.74 19.99±1.74 >0.05 Esters (μg / kg fresh weight) 27.91±3.21 29.60±3.31 >0.05

[0042] Based on the above results, the method described in the invention can effectively delay the ripening process of wine grapes 'Cabernet Sauvignon', but has little effect on the growth and yield of grapevines and key flavor compounds in berries. After field trials for many years, the yield of grapes and the soluble sugar and starch stored in the grapevines were not affected, indicating that the adjustment of the sink-source relationship by this method is within a reasonable range.

[0043] Example 2: Delayed maturity effect of delaying the time of heavy topping of new shoots

[0044] Comparative Example 1 (SST2): The difference from Example 1 is that the heavy topping of new shoots in step (2) is performed on the 10th day after all fruits have changed color (i.e., the 10th day after the color change period ends). The results show that delaying the heavy topping of new shoots until the color change is completed can delay the grape harvest period by 4 to 7 days (Table 3), and the delay effect is obviously not as good as that of Example 1 of the present invention.

[0045] Comparative Example 2 (SST3): The difference from Example 1 is that the heavy topping of new shoots in step (2) is performed at the early stage of the color change period (the first day after entering the color change period). The results show that the grape harvest period can be delayed by 7 to 9 days. Although the effect of delaying ripening is similar to that of Example 1, it has an adverse effect on the growth and coloring of grapes, the grape yield decreases, and the coloring is not good.

[0046] By comparing the above two examples, it is determined that the most appropriate time to remove the new shoots is when the color change is completed.

[0047] Table 3 Phenological period survey at different new shoot treatment time points

[0048]

[0049] Note: SST1, severe topping of new shoots after color change of the present invention; SST2, severe topping of new shoots 10 days after color change of comparative example 1; SST3, severe topping of new shoots at the beginning of color change of comparative example 2; date is expressed as month / day.

[0050] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for delaying grapes, characterized in that: include: The grapes are pruned when the grapes are completed changing color; the pruning includes: removing 1 / 4 to 1 / 3 of the new shoots on the top of the grape leaf curtain.

2. The method according to claim 1, characterized in that The grape color change completion period is the period from 0 to 2 days after all the grape berries are colored and the fruit sugar content is 15.5 to 16.5° Brix.

3. The method according to claim 1, characterized in that The method further comprises the steps of measuring and calculating the leaf curtain area 1 to 3 days before pruning.

4. The method according to claim 3, characterized in that The leaf curtain height after pruning is 1.2-1.35 m, and the leaf curtain area is 30%-40% of that before pruning.

5. The method according to any one of claims 1 to 4, characterized in that: The grapes include wine grapes.

6. The method according to claim 5, characterized in that The wine grapes include Cabernet Sauvignon, Marselan, Merlot or Syrah.

7. The method according to any one of claims 1 to 6, characterized in that: Also includes: Tie the new shoots with the tops removed to the vineyard racks in time.

8. The method according to claim 7, characterized in that The binding position of the new shoots is 1.0 to 1.1 m of the leaf curtain height.

9. The method according to any one of claims 1 to 8, characterized in that: Steps to monitor berry maturity during the phenological period are also included.

10. The method according to claim 9, characterized in that The monitoring of berry maturity during the phenological period includes: random berry sampling every 10 days after topping, sugar content testing after crushing and juice extraction, and recording the time when the berry color change is completed and harvested.

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