IMPROVING THE YIELD OF PLANTS

Abstract: The invention relates to the exogenous use of betaine to improve the yield of grapevines. According to the invention, betaine is used to improve the yield especially under stress conditions. The invention also relates to grapevines treated exogenously with betaine, to grapes produced by the vines, and to products prepared from the grapes.

Description: Improving the yield of plants Technical field The invention relates to the use of betaine to improve the yield of plants. The invention relates especially to the use of betaine to improve the yield of grapevine. According to the invention, the yield can be improved particularly under stress conditions, i.e. when the conditions are poor due to e.g. low temperatures, drought, high salinity or environmental poisons interfering with the growth. The invention also relates to grapevines treated with betaine, to grapes produced by the grapevines, and to products prepared from the grapes. Background The environment and conditions of growth considerably affect the yield of plants. Optimum growth environment and conditions usually result in a yield that is large in quantity and high in quality. Under poor growth conditions both the quality and the quantity naturally deteriorate. Several different solutions have been developed to improve the growth conditions and yield of plants. Selecting the right plant for the right growth location is self-evident for a person skilled in the art. During the growing season plants may be protected with mechanical means by utilizing for example different gauzes or plastics or by cultivating the plants in greenhouses. Irrigation and fertilizers are generally used in order to improve the growth. The physiological properties of a plant are manipulated by means of breeding, both with traditional breeding methods and for example with genetic manipulation. The methods are often laborious and impractical, their effect is limited (the economical size of a greenhouse, the limited protection provided by gauzes, etc.), and they are also far too expensive on a global scale. No economically acceptable chemical solutions for protecting plants from environmental stresses have been described so far. Viticulture is economically a very significant part of agriculture. Wines of the important wine- producing countries, such as France, Italy, Australia and the United States, are the most valuable products on the world market. However, vineyards that produce grapes used in the production of these premium wines hesitate to increase the yield, since yield-increasing cultural and management practices, such as the use of fertilizers, have a negative effect on grape juice and thereby also on the quality of wine. In order to maintain a good wine quality, the size of the grapes should be maintained in the characteristic size of the variety. The flavour compounds are derived from the peel of the grape, and therefore if the fruit size is increased by e.g. fertilizers, the flavour compounds are reduced and the quality of the wine deteriorates. Yield- increasing practices also reduce the sugar content of grape juice and alter the juice pH. This again effects the fermentation processes and final wine quality. One of the reasons for the reduced yield of grapes is the low temperature and water stress interfering with the cultivation conditions in several vineyards. Plants can adapt to some extent to stress conditions. As a result of the aforementioned stress conditions, plants begin to produce a growth hormone called abscisic acid (ABA), which helps the plants to close their stomata, thus reducing the severity of stress. However, ABA also has harmful side effects on the productivity of plants. ABA causes for example leaf, flower and young fruit drop and inhibits the formation of new leaves, which naturally leads to reduction in yield. It has been detected that under stress conditions for example proline and betaine are accumulated in the regions of growth of certain plants. The literature of the art discusses the function and meaning of these accumulated products. On the one hand it has been proposed that the products are by-products of stress and thus harmful to the cells, on the other hand it has been estimated that they may protect the cells (Wyn Jones, R.G. and Storey, R. : The Physiology and Biochemistry of Drought Resistance in Plants , Paleg, L.G. and Aspinall, D. (Eds. ), Academic Press, Sydney, Australia, 1981). Zhao et al. (in J. Plant Phyεiol . 140 (1992) 541 - 543 ) describe the effect of betaine on the cell membranes of alfalfa. Alfalfa seedlings were sprayed with 0.2M glycinebetaine, whereafter the seedlings were uprooted from the substrate, washed free of soil and exposed to temperatures from -10°C to -2°C for one hour. The seedlings were then thawed and planted in moist sand for one week at which time regrowth was apparent on those plants that had survived. Glycinebetaine clearly improved the cold stability of alfalfa. The effect was particularly apparent at -6°C for the cold treatment. All controls held at -6 C C for one hour died, whereas 67% of the seedlings treated with glycinebetaine survived. Itai and Paleg (in Plant Science Letters 25 (1982) 329 - 335) describe the effect of proline and betaine on the recovery of water-stressed barley and cucumber. The plants were grown in washed sand, and polyethylene glycol (PEG, 4000 ol. wt. ) was added to the nutrient solution for four days in order to produce water stress, whereafter the plants were allowed to recover for four days before harvesting. Proline and/or betaine (25 mM, pH 6.2) was sprayed on the leaves of the plant either on the first or third day of the stress or immediately before harvesting. As regards barley, it was noted that betaine supplied either before or after the stress had no effect, whereas betaine added in the end of the stress was effective. Proline had no effect. No positive effect was apparent for cucumber. On the contrary, it was found out that both betaine and proline had a negative effect. Brief description of the invention In connection with the present invention it has now surprisingly been found that the yield and crop quality of grapevine can be considerably improved by means of betaine that is applied exogenously. Betaine has been found to be especially effective in improving the yield under stress conditions, and it has no such detrimental effects as the side effects of ABA. The invention thus relates to the exogenous use of betaine to improve the yield of grapevine. The invention also relates to grapes produced by grapevines treated exogenously with betaine, and to the use of the grapes as such or as a raw material for food industry, such as wine, juice and brewing industry. Grapes can naturally also be used for other purposes, for example in spices, sweets, jams, etc. The invention also relates to a method of improving the yield of grapevine, in which method betaine is exogenously applied to a growing grapevine. The invention further relates to grapes provided by grapevines treated exogenously with betaine. Betaine is applied to the plant in either one or several successive treatments. The application may be performed for example by spraying together with some other spraying of fertilizers or pesticides, if desired. Betaine utilized according to the invention is transported to the plant cells, actively regulates the osmotic balance of the cells and also participates in other processes of cell metabolism. A cell treated with betaine is more viable even when subjected to exogenous stress factors. The betaine treatment according to the invention is economically advantageous, and the yield increases in an amount that is economically profitable and significant. The treatment does not produce significantly more work since it may be performed together with other sprayings of fertilizers or pesticides, and it does not require new investments in machinery, equipment or space. It should also be noted that betaine is a non-toxic natural product, which has no detrimental effects on the quality of the yield. Betaine is also a stable substance that remains in the plant cells and thereby has a long-standing effect. Detailed description of the invention Betaine refers to fully N-methylated a ino acids. Betaines are natural products that have an important function in the metabolism of both plants and animals. One of the most common betaines is a glycine derivative wherein three methyl groups are attached to the nitrogen atom of the glycine molecule. This betaine compound is usually called betaine, glycinebetaine or trimethylglycine, and its structural formula is presented below: CH, CH, N * - CH 2 COO " CH 3 Other betaines are for example alaninebetaine and prolinebetaine, which has been reported to for example prevent perosis in chicks. R.G. Wyn Jones and R. Storey describe betaines in detail in The Physiology and Biochemistry of Drought Resistance in Plants (Paleg, L.G. and Aspinall, D. (Eds.), Academic Press, Sydney, Australia, 1981). Betaine has a bipolar structure and it contains several chemically reactive methyl groups which it can donate in enzyme-catalyzed reactions. Most organisms can synthesize small amounts of betaine for example for the methyl function, but they cannot react to stress by substantially increasing the production and storage of betaine. Best known organisms accumulating betaine are plants belonging to the Chenopodiaceae family, for example sugar beet, and some microbes and marine invertebrates. The main reason for the betaine accumulation in these organisms is probably that betaine acts as an osmolyte and thus protects the cells from the effects of osmotic stress. One of the main functions of betaine in these plants and microbes is to increase the osmotic strength of the cells when the conditions require this, for example in case of high salinity or drought, thus preventing water loss. Unlike many salts, betaine is highly compatible with enzymes, and the betaine content in cells and cell organelles may therefore be high without having any detrimental effect on the metabolism. Betaine has also been found to have a stabilizing effect on the operation of acromolecules; it improves the heat resistance and ionic tolerance of enzymes and cell membranes. Grapevines do not normally store betaine in their cells. Betaine can be recovered for example from sugar beet with chromatographic methods. Betaine is commercially available for example under the trademark of BETAFIN, Cultor Oy, Finnsugar Bioproducts. BETAFIN is crystalline water-free betaine of Finnsugar Bioproducts. Other betaine products, such as betaine monohydrate, betaine hydrochloride and raw betaine liquids, are also commercially available and they can be used for the purposes of the present invention. According to the present invention, betaine is used exogenously in order to improve the yield of grapevine. According to the invention, betaine is used to improve the yield of grapevine especially under stress conditions, i.e. when the plants are subjected to periodic or continuous exogenous stress. Such exogenous stress factors include for example drought, humidity, low or high temperatures, high salinity, herbicides, environmental poisons, etc. Treating plants subjected to stress conditions exogenously with betaine for example improves the adaptation of the plants to the conditions and maintains their growth potential longer, thereby improving the yield-producing capacity of the plants. Betaine is also a stable substance that remains in the plant cells. The positive effect of betaine is thereby long-standing and diminishes only gradually due to dilution caused by the growth. Betaine is applied to grapevines in either one or several successive treatments. Application in a single dose is considered preferable. The amount used varies depending on the grapevine variety and the phase of growth. A useful amount can be for example about 0.1 to 20 kg of betaine per hectare. A preferable amount is thus for example about 4 kg of betaine per hectare. The amounts given here are only suggestive; the scope of the present invention thus contains all amounts that work in the manner described herein. Any method suitable for the purpose can be utilized for the application of betaine. Betaine can easily be spread for example through spraying. Such spraying can be performed together with some other spraying of fertilizers or pesticides, if desired. According to the invention, an aqueous solution of betaine is preferably used. The time of the treatment according to the invention may vary, too. If betaine is applied in a single treatment, the treatment is usually performed at an early stage of growth, for example immediately after the leaves have come out. If betaine is applied in two successive treatments, the second spraying is performed preferably in the beginning of flowering or when stress can be forecasted on the basis of the weather. The betaine treatment according to the invention considerably improves the yield of grapevines. The treatment according to the invention is economically advantageous and the increase in the yield is economically profitable and significant. This invention has provided evidence that the yield of grapevine can be increased by as much as 50% by utilizing a suitable betaine application rate, for example about 4 kg/ha. It should also be noted that even though the yield increases to such a considerable extent, the quality does not deteriorate. It has been shown in this invention that for example the cold resistance and drought resistance of grapevines can be considerably improved with the betaine treatment according to the invention without deterioration in the quality. In a vineyard, yield is determined on the basis of several factors, such as the number of bunches, number of grapes per bunch or bunch weight and grape size, measured for example on the basis of the weight of 100 grapes. In the present invention, the increase in yield resulted from an increased number of bunches and not from an increase in the grape size. There was no significant change in the number of grapes per bunch, either. However, the bunches of grapevines treated with betaine were very compact and well filled. Betaine can thus prevent flower/fruit drop, and this is a clear indication of the positive effects of betaine application on plants. The invention will be described in greater detail by means of the following examples. These examples are only provided to illustrate the invention, and they should not be considered to limit the scope of the invention in any way. Statistical analysis of the results presented in the examples was performed by means of variance analysis utilizing Genstat or Ministat statistical package. Example 1 The effect of betaine on grapevine yield was determined under field conditions utilizing four different betaine concentrations: 0 (control), 1, 2 and 4 kg of betaine per hectare. An aqueous solution of betaine was used in the experiment, the betaine content of the solution being 12 g/1. The solution also contained 2 ml/1 of non-ionic wetter, Plus-50 (Ciba Geigy). The amount of betaine solution applied was about 350 1/ha or 64 1/1000 m of a cultivated row, and the application was performed always on each side of the row in order to ensure that the plants were uniformly treated with betaine. The grapevines were otherwise cultivated in a normal manner without irrigation, and they were periodically plagued by drought and cold weather; the temperature varied between about 3 and 30°C. The grapevine cultivar was Pinot Noir. Four uniform-looking vines were selected during budburst. When there was about 50% budburst, but before any flower opening, two of the plants were treated with a single dose of a certain concentration of betaine, whereas the other two vines received at this stage only half of the selected betaine concentration and the remaining dose was applied a month later in the beginning of flowering. A single application of betaine was found to be more effective than several applications. When the grapes were ripe, the bunches were picked and the yield was calculated by converting the number of grapes provided by two vines into a yield per hectare on the basis of the number of vines growing within one hectare. The number of bunches per vine was calculated by dividing the total number of bunches of two vines by two. The experiment showed that a single betaine dosage of 2 kg/ha or 4 kg/ha provided a considerably greater yield. The best result was obtained with the dosage of 4 kg/ha, whereupon the yield increased from a control value of 6.5 t/ha to 9.8 t/ha. This signifies a net increase of 3.3 t/ha, i.e. the yield increase was about 51% over the control. The number of grape bunches also increased significantly when betaine was applied in an amount of 2 kg/ha or more. In this case too, the best result was obtained with the betaine application rate of 4 kg/ha. The results are shown in Table 1. Table 1 Effect of betaine treatment on grapevine yield Betaine number of grapes number of (kg/ha) (t/ha) bunches 0 6.5 28.4 1 7.1 31.8 2 9.1 36.2 4 9.8 37.0 Example 2 The experiments described in Example 1 were repeated utilizing betaine concentrations of 0, 2, 4, 6 and 8 kg/ha, applied in a single dose. There were 4 plants for each application, but otherwise the test arrangements were similar to Example 1. The best results were also obtained here with the betaine dosage of 4 kg/ha. The number of grapes also increased significantly when betaine was added in the amount of 4 kg/ha. A greater amount of betaine did not further increase the number of bunches. The results are shown in Table 2. Table 2 Effect of betaine treatment on grapevine yield Betaine number of grapes number of (kg/ha) (t/ha) bunches 0 4.4 137 2 5.2 150 4 6.0 170 6 5.1 144 8 4.6 138 Example 3 The effects of betaine treatment on the quality of grapes were examined by determining the weight of bunches, the weight of 100 grapes, and the pH and Brix of grape juice of vines cultivated under the conditions described in Examples 1 and 2. The weight of the bunches was calculated by dividing the total yield of two vines by the number of bunches, and the weight of 100 grapes was calculated by diving by two the weight of 200 grapes picked at random. Brix is the measure of the solute content of grape juice, and most of this content is sugar. There were no statistically significant changes in the weight of bunches and the weight of 100 grapes as a result of the betaine application. There were no statistically significant changes in the pH and Brix of grape juice as a result of the betaine application, either. On the basis of the results, the betaine application did not have a negative effect on the quality of the grapes despite the considerable increase in the yield. Some of the results are shown in Table 3. Table 3 Effect of betaine treatment on the pH and Brix of grape juice pH Brix Betaine 1. 2. 1. 2. (kg/ha) 0 3.48 3.49 17.3 17.9 1 3.51 3.49 17.2 17.6 2 3.46 3.52 16.4 17.8 4 3.50 3.56 17.9 18.1 1. Application in a single treatment. 2. Application in two successive treatments,

Claims: Claims 1. Exogenous use of betaine to improve the yield of grapevines. 2. Use according to claim 1, c h a r a c¬ t e r i z e d in that betaine is used under stress conditions in order to improve the yield of grapevines. 3. Use according to claim 2, c h a r a c- t e r i z e d in that the stress conditions comprise high or low temperatures, drought, excess humidity, or high salinity. 4. Use according to any one of claims 1 to 3, c h a r a c t e r i z e d in that betaine is used in an amount of about 0.1 to 20 kg/ha. 5. Use according to claim 4, c h a r a c¬ t e r i z e d in that betaine is used in an amount of about 4 kg/ha. 6. A method for improving the yield of grapevines, c h a r a c t e r i z e d in that betaine is exogenously applied to growing grapevines. 7. A method according to claim 6, c h a r a c t e r i z e d in that betaine is applied to grapevines growing under stress conditions. 8. A method according to claim 6 or 7, c h a r a c t e r i z e d in that the stress conditions comprise high or low temperatures, drought or excess humidity. 9. A method according to any one of claims 6 to 8, c h a r a c t e r i z e d in that betaine is applied once or several times during the growing season. 10. A method according to any one of claims 6 to 9, c h a r a c t e r i z e d in that betaine is applied together with a pesticide, fertilizer or surfactant. 11. A method according to any one of claims 6 to 10, c h a r a c t e r i z e d in that betaine is applied in a single treatment at an early stage of growth. 12. A method according to any one of claims 6 to 11, c h a r a c t e r i z e d in that betaine is used in an amount of about 0.1 to 20 kg/ha, preferably about 4 kg/ha. 13. Grapes obtained with a method according to any one of claims 6 to 12. 14. Grapevines treated exogenously with betaine and the products thereof.

Inventors: BODAPATI NAIDU, VIRTANEN ERKKI, BODAPATI, NAIDU, VIRTANEN, ERKKI
Applicants: BODAPATI NAIDU, CULTOR OY, VIRTANEN ERKKI, BODAPATI, NAIDU, VIRTANEN, ERKKI
Application year: 1995
Main classification: A01N37
IPC codes: A01N37