A method for delaying the ripening of wine grapes

Abstract

The present application relates to the technical field of grape cultivation, and particularly relates to a method for delaying maturity of wine grape, which comprises the following steps: pruning the grape at the completion period of grape color change; the pruning comprises the following steps: removing the new shoots of 1 / 4-1 / 3 of the top of grape leaf curtain. Experiments show that the method can effectively delay the maturity process of wine grape, can delay the harvest period of grape by 6-11 days, and does not affect the yield of vineyard and the quality of wine grape. The method is simple in operation, and has high reproducibility through years of repeated field test verification, can be used to solve the problem of too fast maturity in the western production area of China, and is an effective method for delaying grape maturity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of grape cultivation, and particularly relates to a method for delaying the ripening of wine grapes. BACKGROUND

[0002] Grape (Vitis vinifera L.) is very sensitive to changes in climatic conditions. In the past few decades, the wine industry has been deeply 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 five decades, the average temperature in western China has risen by about 2℃, and the increase in average temperature during the growing season can also reach about 1.6℃ (Liu et al., 2022, Distal leaf 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 regions, climate warming enables grapes to reach the ideal maturity, while in hot regions, climate warming has led to a series of problems, and the disconnection between sugar content and flavor compounds of grapes has brought challenges to winemakers. Therefore, finding suitable low-cost and labor-saving techniques, especially developing techniques for delaying ripening in grape cultivation, is the focus of attention of winemakers and researchers.

[0004] In the wine grape production area of western China, the climate is relatively dry, and the development process of grapes is prone to be stressed by heat wave and strong light, so grape growers usually choose thicker leaf canopy to protect grapes from sunburn, which leads to higher leaf-fruit ratio of grape tree body. This leads to the acceleration of ripening process and the excessive speed of sugar accumulation during grape ripening, so that the grape matures in more high-temperature weather, resulting in the lack of typical flavor of grape. At present, there is still a lack of a simple and effective method that can be applied to delay grape ripening in western China. In view of the increasingly adverse effects of global warming on western China, it is necessary to establish a cultivation technique that can delay grape phenology and balance the source-sink relationship of grape tree body. SUMMARY

[0005] Therefore, the present application provides a method for delaying the ripening of wine grapes. The method can delay the harvest of grapes by 6-11 days without affecting the yield and quality of wine grapes. Moreover, the method is simple and has high reproducibility

[0006] A method for delaying grape ripening, comprising: pruning grapes at the completion of grape color change; the pruning comprises: removing 1 / 4-1 / 3 of the new shoots at the top of the grape leaf canopy.

[0007] In the present application, the pruning period is specifically: the period of 0-2 days after the grape berries are fully colored and the sugar content of the fruit is 15.5-16.5 °Brix. The day when the grape berries are fully colored is the 0th day, and the following days are sequentially recorded as the 1st day, the 2nd day. 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 application, the removal of new shoots at the top of the grape leaf canopy is to the height of the leaf canopy after pruning, which is 1.2-1.35 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 application, the removal of new shoots at the top of the grape leaf canopy is to the area of the leaf canopy after pruning, which is 30%-40% of the area before pruning, specifically 30%, 32%, 34%, 36%, 38%, 40%.

[0010] In the present application, 1-3 days before pruning also includes the steps of measuring and calculating the area of the leaf canopy. In some embodiments, the steps of measuring and calculating the area of the leaf canopy include: randomly selecting ten new shoots for leaf area measurement for each repetition, a total of three repetitions. Further, the method for measuring the leaf area is: measuring the leaf area in situ on the new shoots using a Yaxin-1242 leaf area meter.

[0011] The grape in the method for delaying grape ripening includes wine grape. The wine grape includes Cabernet Sauvignon, Merlot, Malbec or Syrah. In some specific embodiments, the grape is wine grape. The method for delaying grape ripening is verified by taking Cabernet Sauvignon as an example, and the method can delay grape harvest period by 6-11 days without affecting the yield and wine quality of Cabernet Sauvignon.

[0012] In the method, the new shoots removed from the top are timely bound on the trellis surface of the vineyard. In some embodiments, the binding position of the new shoots is 1.0-1.1 m of the leaf curtain height.

[0013] In the method, the method further comprises the step of monitoring the berry maturity in the phenological stage.

[0014] In some embodiments, the monitoring of the berry maturity in the phenological stage comprises: randomly sampling the berries every 10 days after the defoliation, detecting the sugar content after crushing the juice, and recording the time of berry color change completion and harvest.

[0015] In some specific embodiments, the method for delaying grape ripening comprises the following steps:

[0016] (1) The time of heavy defoliation of the new shoots: the wine grape is subjected to leaf curtain management when the color change of the grape berries is completed, specifically when the grape berries are completely colored;

[0017] (2) Measurement and calculation of the leaf area: the measurement of the leaf area is performed 1-3 days before the leaf curtain treatment. Ten new shoots are randomly selected for the measurement of the leaf area in each repetition, and the measurement is performed three times;

[0018] (3) The method of heavy defoliation of the new shoots: the height of the leaf curtain and the new shoots is measured, and the length of the new shoots to be cut is controlled to be 0.45 m in the grape vineyard in the western region with a leaf curtain height of about 1.8 m. The new shoots are cut using a gardening pruning shears, and the remaining leaf area after cutting is measured to ensure that the cut leaf area is 30%-40% of the whole leaf area;

[0019] (4) Management of the new shoots after defoliation: the new shoots are timely bound on the trellis surface of the vineyard after defoliation to ensure the neatness of the leaf curtain and prevent the leaf curtain from being loose to cause excessive exposure of the clusters;

[0020] (5) Monitoring of the berry maturity in the phenological stage: random berry sampling is performed every 10 days after defoliation, sugar content detection is performed after crushing the juice, and the time of berry color change completion and harvest is recorded.

[0021] The present application provides a method for delaying the maturity of wine grapes, which comprises pruning the grapes at the completion of the grape color change period; the pruning comprises removing 1 / 4-1 / 3 of the new shoots at the top of the grape leaf canopy. Experiments show that the method can effectively delay the maturity process of wine grapes, can delay the grape harvest period by 6-11 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 years of field repeated tests, has high reproducibility, can be used to solve the problem of too fast maturity in the western production area of China, and is an effective method for delaying grape maturity. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Schematic diagram of heavy top removal of new shoots;

[0023] Figure 2 Effect of heavy top removal of new shoots in Example 1 on the soluble solids (TSS), titratable acid (TiA), pH and 100 berries weight of 'Cabernet Sauvignon' grapes. DETAILED DESCRIPTION

[0024] The present application provides a method for delaying the maturity of wine grapes. Those skilled in the art can improve the process parameters as appropriate to achieve the method. In particular, it should be pointed out that all similar substitutions and changes are obvious to those skilled in the art, and they are considered to be included in the present application. The method and application of the present application have been described by the preferred embodiments, and the relevant personnel can obviously make changes or appropriate changes and combinations to the method and application herein without departing from the content, spirit and scope of the present application, to realize and apply the present application technology.

[0025] The test materials used in the present application are all ordinary commercially available products, which can be purchased in the market.

[0026] The present application will be further described below in conjunction with examples:

[0027] Effect of heavy top removal of new shoots on the maturity process of 'Cabernet Sauvignon' grapes in Manasi production area

[0028] This example was carried out in a commercial vineyard in Manasi region of northwest China (44°24'N-86°26'E, altitude 522m), which belongs to a temperate continental semiarid climate. The test material was Cabernet Sauvignon grape, self-rooted seedlings, planted in 2011, using modified VSP shaping, with a plant spacing of 1m x 3m. The vineyard direction was northeast-southwest (52°), with 18-22 nodes per extended meter, and the fruit retention amount was 27-33 clusters. The grape trees were furrow irrigated at the bud stage, flowering stage, pea size, color change stage and harvest stage (about three weeks before harvest), with an irrigation amount of 750m 3 ·ha -1Three adjacent rows in the vineyard were selected. In 2018-2020, 45 grapevines with uniform growth were selected in each row, and heavy shoot thinning was performed, denoted as SST.

[0029] (1) Measurement of leaf area before treatment: Before harvest, 10 grapevines were randomly selected from each treatment, and 3 shoots were randomly selected from each grapevine. The main and secondary shoot leaf areas were measured using a portable Yaxin-1242 leaf area meter, and 10 shoots were measured for each replicate.

[0030] (2) Heavy shoot thinning: Three years of experiments were conducted: in 2018-2020, all branches and leaves from the top of the canopy to 1.35 meters from the ground were pruned after the grape color change period (August 8, TSS ≈ 16°Brix) (see Figure 1 ), which means that 30%-40% of the new shoots and leaves of the entire canopy were completely removed. The same batch of trees was treated every year.

[0031] (3) Measurement of tree growth potential: At harvest, the weight of 10 clusters was measured for each replicate to estimate yield. During winter pruning, the pruning amount of 10 trees was measured for each replicate, the length of the new shoot and the diameter of the third node at the base were measured, and the load was calculated by yield / pruning amount. Anthrone colorimetric method was used to determine the soluble sugar and starch content of the third node of the new shoot.

[0032] (4) Measurement of grape components: The weight of 100 berries was measured using an electronic balance (precision 0.01 g). The soluble solids content was measured using a hand-held refractometer (PAL-1, Atago, Japan), and the pH was measured using a pH meter. The sugar accumulation rate (mg / berry / d) was calculated based on the soluble solids content of the berries and the mass of the berries. The juice titratable acid was titrated with a NaOH standard solution, and the results were expressed as tartaric acid (g / L). The flavonoid content in the grape was measured using an Agilent 1200 series equipped with a 6410 triple quadrupole mass spectrometer (QqQ). The Poroshell 120 EC-C 18 column was used, 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. The mobile phase A was 0.1% (v / v) formic acid in water, and the mobile phase B was 0.1% (v / v) formic acid in 50 / 50 (v / v) methanol / acetonitrile. The elution program was as follows: 10% to 100% B phase for 15 min, followed by a 5 min post-run program; the acquisition parameters for the ion trap mass spectrometer detector were as follows: electrospray ion source, positive ion mode, ion scan range 100-1500 m / z, atomizer pressure 35 psi, dry gas flow rate 12 L / h, and dry gas temperature 350°C. The aroma compounds in the grape were measured using an Agilent 6890 series gas chromatograph-mass spectrometer. The carrier gas was high-purity helium, and the flow rate was 1 mL / min. The temperature program was as follows: 50°C for 1 min, then 3°C / min to 220°C, and finally 5 min at 220°C. The remaining conditions were as follows: injection port temperature 250°C, detection of grape juice in splitless mode, ionization by electron ionization (EI) source, ionization energy 70 ev, ion source temperature 230°C, mass spectrometer interface temperature 280°C, and mass scan range 30-350 u.

[0033] (4) Results: The effects of severe shoot thinning on grapevine growth and harvest time in three consecutive years are shown in Table 1. Severe shoot thinning significantly affected vine growth. Shoot thinning significantly reduced the leaf area, leaf to fruit ratio, and average shoot length of the new shoots, main shoots, and secondary shoots. The total leaf area was reduced by 36%, and the leaf area of the main shoots was reduced by 34-48%. Severe shoot thinning had no significant effect on yield, which was also reflected in the number of berries and cluster weight. For grapevine nutrient storage, severe shoot thinning in 2019 significantly reduced the soluble sugar content in the shoots (p<0.05). There was no significant difference in starch content. Severe shoot thinning delayed the harvest time of the grape by 6-11 days.

[0034] Table 1 Effects of severe shoot thinning on grapevine growth and harvest time in three consecutive years

[0035]

[0036]

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

[0038] The effect of severe shoot defoliation on berry composition of Cabernet Sauvignon is shown in Table 1 and Table 2. Figure 2

[0039] The results show that the severe shoot defoliation significantly inhibited the sugar accumulation rate, and decreased 0.6 mg / berry / d. The effect on titratable acid, pH and berry weight was small. Further analysis of secondary metabolites in the berry, severe shoot defoliation did not affect the flavonoids and aroma compounds in the berry.

[0040] Table 2 Effect of severe shoot defoliation on main flavor substances in grape fruit

[0041] Indicators C SST Significance (t-test) Anthocyanins (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 Norisoprenoids (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] In summary, the method of the present application can effectively delay the ripening process of wine grape Cabernet Sauvignon, but has little effect on the growth of grapevines, yield and key flavor compounds in the berry. After several years of field trials, the yield of grape and the storage of soluble sugar and starch in grapevines were not affected, indicating that the adjustment of the sink-source relationship by this method is within a reasonable range.

[0043] Example 2: Effect of delaying the time of severe shoot defoliation on delaying ripening

[0044] Comparative Example 1 (SST2): The difference from Example 1 is that the severe shoot defoliation in step (2) is performed on the 10th day after the fruit is fully colored (i.e. 10 days after the end of the coloring period). The results show that delaying the severe shoot defoliation until the coloring is completed can delay the harvest period of the grape by 4-7 days (Table 3), and the delaying effect is obviously not as good as that of Example 1 of the present application.

[0045] Comparative Example 2 (SST3): The difference from Example 1 is that the severe shoot defoliation in step (2) is performed at the beginning of the coloring period (1 day after entering the coloring period). The results show that the harvest period of the grape can be delayed by 7-9 days, although the effect of delaying ripening is similar to that of Example 1, but it has an adverse effect on the growth and coloring of the grape, and the yield of the grape decreases, and the coloring is not good.

[0046] Through the comparison of the above two examples, it is determined that the completion of coloring is the most appropriate time for shoot defoliation.

[0047] ​Table 3. Investigation of phenophase at different new shoot treatment time points

[0048]

[0049] Note: SST1, heavy topping of new shoots after color change of the application; SST2, heavy topping of new shoots 10 days after color change of Comparative Example 1. SST3, heavy topping of new shoots at the beginning of the color change period of Comparative Example 2; dates are expressed as month / day.

[0050] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and not limit the present application. Although the present application 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 application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. A method for delaying grape ripening, characterized in that, include: Prune the grapevines when the veraison stage is complete; the pruning includes removing 1 / 4 to 1 / 3 of the new shoots from the top of the grape canopy; The grape veraison completion period is the period from 0 to 2 days after the grape berries have fully colored and the fruit sugar content is 15.5 to 16.5 °Brix. The height of the pruned leaf canopy is 1.2~1.35m, and the area of ​​the leaf canopy is 30%~40% of that before pruning.

2. The method according to claim 1, characterized in that, The grapes mentioned include wine grapes.

3. The method according to claim 2, characterized in that, The grapes used for winemaking include Cabernet Sauvignon, Marselan, Merlot, or Syrah.

4. The method according to claim 1, characterized in that, Also includes: The new shoots with their tops removed should be tied to the vineyard trellis in a timely manner.

5. The method according to claim 4, characterized in that, The new shoots are tied at a height of 1.0 to 1.1 m above the canopy.

6. The method according to any one of claims 1 to 5, characterized in that, It also includes steps for monitoring berry ripening during phenological periods.

7. The method according to claim 6, characterized in that, The monitoring of berry maturity during the phenological period includes: randomly sampling berries every 10 days after topping, crushing and extracting juice to test sugar content, and recording the time of berry color change completion and harvest.

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