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Abstract With the grape variety "Summer Black" as the test material， the effects of different shoot??fruit ratios on grape yield， fruit quality and grapevine storage nutrient were investigated for 2 consecutive years， so as to determine the optimized load for Summer Black grapes in Shandong. The results showed that the grapes with shoot??fruit ratio of 1?? 1 had the highest soluble solid content， vitamin C content and grapevine storage nutrient. Based on the comprehensive analysis， the shoot??fruit ratio of 1?? 1 was the optimized load for Summer Black grapes in Tai??an of Shandong Province， and the yield was 1 179.37-1 288.63 kg per 667 m2.
Key words Shoot??to??fruit ratio； Summer Black； Yield； Fruit quality； Storage nutrient
The Summer Black grape is a triploid variety from the cross of Vitis vinifera and V. Labrusca. The berries are tightly??shaped， nearly round， and the fruit clusters are neatly sized. Summer black grapes are blackish??purple， with a sweet taste of rich strawberry flavor， and have good fresh food quality. Because of its early maturity， excellent quality， disease resistance， high yield and tolerances to storage and transportation， the Summer Black grape is very popular among consumers， and the planting area has expanded year by year. It has become the main planting variety in many places[1-2]. In the process of production and cultivation， there is a common problem of pursuing high yield with large amount of fruit retention， which not only causes problems such as poor coloration of the fruit， oversized panicle shape， low sugar content， but also affect the tree growth and flower bud differentiation of the second year[3-4]. If the load is too low， the vegetative growth of the plant will be strong. Although the fruit quality is improved， the yield is reduced， and it will also affect the economic benefits[5]. Therefore， reasonable load is an important measure to ensure tree growth and to obtain high yield， stable yield and high quality. In this study， the effect of load on the yield， fruit quality and grapevine storage nutrient of Summer Black grape was investigated through setting treatments with different shoot??fruit ratios， with the aim to provide theoretical bases for the management of Summer Black grape load in Tai??an， Shandong Province.
Materials and Methods
Test materials
Tests were conducted in the Jinniushan Grape Demonstration Base of Shandong Institute of Pomology from 2015 to 2016. The tested variety was the cutting seedlings of 3??year??old Summer Black grapes， which were in the north??south direction with plant spacing of 5 m ?? 2 m. There were 2 seedlings in a hole， trimmed in T??shape. Others were in accordance with normal field management. After fruit setting， the plants with the same growth were selected to proceed with the load treatments according to the shoot??fruit ratio of 3?? 1， 2?? 1， 1.5?? 1， 1?? 1， 1?? 1.5， 1?? 2， respectively. There were 10 plants in each treatment， and each treatment had 3 repetitions. Samples were taken at the fruit mature period （August 20， 2015， and August 21， 2016）， and all the fruits of 10 plants were randomly collected from each treatment. The 1??year??old grapevines of each treatment were collected during the dormant period （on December 26 in both 2015 and 2016）. Determination items and methods
During the fruit mature period， all the fruits of 10 plants in each treatment were randomly collected， and the yield per plant was calculated， which was equivalent to the yield of 667 m2. The soluble solid content was determined by a digital hand??held saccharimeter， the titratable acid content was determined by acid??base titration， and the vitamin C content was determined by the 2，4??dinitrophenylhydrazine method. The storage nutrient index in grapevines were determined as follows： starch and soluble sugar content were determined by anthrone colorimetric method， soluble protein content was determined by Coomassie Brilliant Blue G??250 method， and free amino acid content was determined by ninhydrin colorimetric method[6]. Statistical analysis of the data was performed using Excel 2003 and DPS software. One??way ANOVA analysis of variance and LSD were used for the significance test.
Results and Analysis
Effect of shoot??fruit ratio on fruit yield
The results of 2 consecutive years of tests showed that with the decrease of the load， the yield of Summer Black grape showed a downward trend. The general trend was consistent in 2015 and 2016. In 2016， the yield of plants with shoot??fruit ratio of 1?? 1 was significantly higher than that of 1?? 1.5. There was no significant difference in the yield between the low load treatments with shoot??fruit ratios of 2?? 1 and 3?? 1. For the treatments with high loads， the yields with shoot??fruit ratios of 1?? 2 and 1?? 1.5 in 2016 were slightly reduced from those in 2015 （Table 1）.
Effect of shoot??fruit ratio on fruit quality
The test results showed that the quality of Summer Black grape increased with the decrease of load. The soluble solids in 2015 and 2016 were the highest at the shoot??fruit ratio of 1?? 1， which were significantly higher than those with the shoot??fruit ratios of 1?? 2 and 1?? 1.5， while the content was the lowest with the shoot??fruit ratio of 1?? 2， which was significantly lower than that of the other 5 treatments. In terms of titratable acid content， the treatment with shoot??fruit ratio of 1?? 1.5 was the lowest in both 2015 and 2016， and the highest was found in the treatment with shoot??fruit ratio of 1?? 2 in 2015 and 2016， which was significantly higher than tat of the other treatments. As for solid??acid ratio， the highest was found in the treatment with shoot??fruit ratio of 2?? 1 in 2015 and 1.5?? 1 in 2016， while the lowest was found in the treatment with shoot??fruit ratio of 1?? 2 in both 2015 and 2016. For Vitamin C content， the highest was found with the shoot??fruit ratio of 1?? 1 for the 2 years， which was significantly higher than that of the other treatments. According to the comprehensive performances of all the indicators， the fruit quality was the best with the shoot??fruit ratio of 1?? 1 （Table 2）. Effect of shoot??fruit ratio on grapevine storage nutrient
The test results showed that with the decrease of the load， the storage nutrient indexes of Simmer Black grapevines increased first. The soluble sugar content was the highest at the shoot??fruit ratio of 1?? 1， followed by that of 1.5?? 1， 3?? 1， and it was the lowest in the treatments with shoot??fruit ratio of 1?? 2， 1?? 1.5. In terms of starch content， the highest was found at the shoot??fruit ratio of 3?? 1 for the 2 years， and there was no significant difference between the shoot??fruit ratio of 1?? 1 and 3?? 1 in 2015， both of which were significantly higher than that of the other treatments. In 2015， the free amino acid content was the highest in treatments with shoot??fruit ratios of 3?? 1， 2?? 1 and 1.5?? 1， which showed no significant difference between each other， followed by the treatment with the ratio of 1?? 1. In 2016， the free amino acid content was the highest in treatments with shoot??fruit ratios of 3?? 1 and 2?? 1 and 1.5?? 1， followed by the treatment with the ratio of 1?? 1. In both 2015 and 2016， the content of free amino acid was the lowest in the high load treatments with shoot??fruit ratios of 1?? 2， 1?? 1.5. The soluble protein content was the highest in the treatments with shoot??fruit ratios of 1?? 1 and 3?? 1 for the 2 years， which had no significant difference between each other， followed by the treatments with the ratios of 1.5?? 1， 2?? 1， and the lowest was found with the shoot??fruit ratio of 1?? 2 and 1?? 1.5. According to the comprehensive performances of all the indicators， the grapevine storage nutrient was the highest with the shoot??fruit ratio of 1?? 1 （Table 3）.
Conclusions and Discussion
The load not only affects the yield and fruit quality of the orchard， but also affects the fruit yield in the second year. In order to ensure the high and stable yield of the grapes， and to produce high??quality， high??grade fruit， the production must be strictly controlled[7]. The results of this study show that the yield with shoot??fruit ratio of 1?? 2 is the highest in the 2 consecutive years， followed by that of 1?? 1 and 1?? 1.5. The high load treatments with shoot??fruit ratio of 1?? 2 and 1?? 1.5 have the yield decreased in 2016 from the yield in 2015. High load can seriously deplete the tree nutrients and reduce the storage nutrient， which can weaken the tree growth and reduce the yield in the next year， resulting in unstable yielding[8]. Therefore， it is necessary to carry out flower and fruits thinning in management to reduce the quantity of fruits and the weight of fruit clusters， and thereby making the tree maintain reasonable growth. Soluble solid content plays an important role in grape quality and is the basic raw material for fruit flavor components and other nutrients[9]. In this study， with the increase of tree load， the yield of Summer Black grape increases gradually， but the content of soluble solids， solid??acid ratio and Vitamin C decrease. The reason is that the high load intensifies the competition for nutrients among fruits， decrease the supply of nutrients in each fruit， and thus delay the fruit maturity to some extent[10]. Low??load fruits have higher soluble solid content， which may be due to the fact that the low load reduces the nutrient competition between fruits and enhances the supply of carbohydrates in fruits， thereby increasing the content of sugars and soluble solids[11]. This is consistent with the results of previous studies on varieties such as Summer Black， Red Globe and Jingya[3， 12-14].
The storage nutrient level of the grapevines not only reflects the cold resistance of the tree， but also determines the sprouting rate of new shoots and the quality of the panicles in the next year[15]. A high storage nutrient level of grapevines is more favorable for overwintering and cold resistance. The comprehensive analysis on the soluble sugar， starch， free amino acid and soluble protein content of the grapevines at each shoot??fruit ratio shows that the performance is the best at the shoot??fruit ratio of 1?? 1. The reason why the storage nutrient indexes decrease in the treatments with shoot??fruit ratios of 2?? 1， 1.5?? 1 is that the unbalanced load can affect the nutrient distribution at the "library" end， resulting in vegetative growth and reproductive growth disorders. At high loads， the reproductive growth is too strong， inhibiting the vegetative growth， which not only consumes the storage nutrients of the grapevines， reducing the nutrient accumulation of the tree， but also reduces the fruit quality.
High or low load can affect the formation of grape yield and the development of grape quality. Therefore， determining the optimized load for Summer Black grape can provide a code standard for stabilizing tree nutrients， increasing yield and improving the commerciality of grapes. According to the comprehensive analysis of yield， fruit quality and grapevine storage nutrient， the performance of Summer Black grape is the best at the shoot??fruit ratio of 1?? 1 under the climatic conditions of Tai??an of Shandong Province， when the yield is 1 179.37-1 288.63 kg per 667 m2， followed by the shoot fruit ratio of 1?? 1.5. Zhen HAN et al. Effect of Shoot??Fruit Ratio on Grape Yield， Quality and Storage NutrientReferences
[1] YANG HC， LIU YR， LIN SC， et al. Introduction performances and cultivation techniques of early??maturing triploid seedless grape Summer Black[J]. South China Fruits， 2006， 35（3）： 74-76.
[2] WANG HX， SHEN JS， CHEN YF. High??quality and high??yield cultivation techniques for grape variety Summer Black in Jinhua， Zhejiang[J]. China Fruits， 2010（4）： 45-47.
[3] LI XJ， LI C， ZHAI H， et al. Effects of different loading amounts on fruit quality of Summer Black grape[J]. Shandong Agricultural Sciences， 2015， 47 （8）： 42-45.
[4] LIU XC， CHI LH， LI YX. Test on the fruit loading of "Jingya" grape[J]. Shaanxi Fruits， 2007， 5（3）： 6-7.
[5] LOU HP. Effects of fruit loads on grape quality and vegetative growth[J]. Journal of Liaoning Agricultural College， 2005， 7（1）： 31-32.
[6] ZHAO SJ， SHI GA， DONG XC. Plant physiology experiment guide[M]. Beijing： China Agricultural Science and Technology Press， 2002.
[7] MAO AN， LIU Q. Study on the relationship between yield and quality traits and load of Kyoho grape in South China[J]. Journal of Fruit Science， 1994， 11（2）： 76-80.
[8] SHI XB， SUN YJ， GAO RG， et al. Effects of rate of fertilizer application and load on yield， quality and nutrient storage of Kyoho grape[J]. Journal of Agricultural University of Hebei， 2012， 35（6）： 12-17.
[9] GUO L， CHEN JL， SONG CN， et al. Effects of girdling time on berry qualities and coloring of Fujiminori??s berry in greenhouse[J]. Sino??Overseas Grapevine and Wine， 2011 （11）： 10-14.
[10] NAOR A， GAL Y， BRAVDO B. Shoot and cluster thinning influence vegetative growth， fruit yield， and wine quality of ??Sauvignon blanc?? grapevines[J]. Journal of American Society for Horticultural Science， 2002， 127（4）： 628-634.
[11] PRAJITNA A， DAMI IE， STEINER TE， et al. Influence of cluster thinning on phenolic composition， resveratrol， and antioxidant capacity in Chambourcin wine[J]. American Journal of Enology and Viticulture， 2007， 58（3）： 346-350.
[12] ZHAO WD， MAN LT， SUN LL， et al. Effect of different trellises and fruit loads on berry quality of grapevine cv. Red Globe[J]. Sino??Overseas Grapevine and Wine， 2010 （11）： 20-22.
[13] DAI ZX， CHEN LR， LIU Q. Effect of the load of Fujiminori grape on fruit development and tree growth[J]. South China Fruits， 1997， 26（3）： 46-47.
[14] LU MD， HE K， PEI QS， et al. Effects of different fruit loads on berry maturity and quality in grape cultivar Yinhong[J]. Journal of Zhejiang University （Agriculture & Life Sciences， 2014， 40（2）： 175-180.
[15] ZHENG XC， WANG HB， WANG XD， et al. Evaluation of cold resistance of 14 grape rootstock varieties[J]. China Fruits， 2014（1）： 36-39.
Key words Shoot??to??fruit ratio； Summer Black； Yield； Fruit quality； Storage nutrient
The Summer Black grape is a triploid variety from the cross of Vitis vinifera and V. Labrusca. The berries are tightly??shaped， nearly round， and the fruit clusters are neatly sized. Summer black grapes are blackish??purple， with a sweet taste of rich strawberry flavor， and have good fresh food quality. Because of its early maturity， excellent quality， disease resistance， high yield and tolerances to storage and transportation， the Summer Black grape is very popular among consumers， and the planting area has expanded year by year. It has become the main planting variety in many places[1-2]. In the process of production and cultivation， there is a common problem of pursuing high yield with large amount of fruit retention， which not only causes problems such as poor coloration of the fruit， oversized panicle shape， low sugar content， but also affect the tree growth and flower bud differentiation of the second year[3-4]. If the load is too low， the vegetative growth of the plant will be strong. Although the fruit quality is improved， the yield is reduced， and it will also affect the economic benefits[5]. Therefore， reasonable load is an important measure to ensure tree growth and to obtain high yield， stable yield and high quality. In this study， the effect of load on the yield， fruit quality and grapevine storage nutrient of Summer Black grape was investigated through setting treatments with different shoot??fruit ratios， with the aim to provide theoretical bases for the management of Summer Black grape load in Tai??an， Shandong Province.
Materials and Methods
Test materials
Tests were conducted in the Jinniushan Grape Demonstration Base of Shandong Institute of Pomology from 2015 to 2016. The tested variety was the cutting seedlings of 3??year??old Summer Black grapes， which were in the north??south direction with plant spacing of 5 m ?? 2 m. There were 2 seedlings in a hole， trimmed in T??shape. Others were in accordance with normal field management. After fruit setting， the plants with the same growth were selected to proceed with the load treatments according to the shoot??fruit ratio of 3?? 1， 2?? 1， 1.5?? 1， 1?? 1， 1?? 1.5， 1?? 2， respectively. There were 10 plants in each treatment， and each treatment had 3 repetitions. Samples were taken at the fruit mature period （August 20， 2015， and August 21， 2016）， and all the fruits of 10 plants were randomly collected from each treatment. The 1??year??old grapevines of each treatment were collected during the dormant period （on December 26 in both 2015 and 2016）. Determination items and methods
During the fruit mature period， all the fruits of 10 plants in each treatment were randomly collected， and the yield per plant was calculated， which was equivalent to the yield of 667 m2. The soluble solid content was determined by a digital hand??held saccharimeter， the titratable acid content was determined by acid??base titration， and the vitamin C content was determined by the 2，4??dinitrophenylhydrazine method. The storage nutrient index in grapevines were determined as follows： starch and soluble sugar content were determined by anthrone colorimetric method， soluble protein content was determined by Coomassie Brilliant Blue G??250 method， and free amino acid content was determined by ninhydrin colorimetric method[6]. Statistical analysis of the data was performed using Excel 2003 and DPS software. One??way ANOVA analysis of variance and LSD were used for the significance test.
Results and Analysis
Effect of shoot??fruit ratio on fruit yield
The results of 2 consecutive years of tests showed that with the decrease of the load， the yield of Summer Black grape showed a downward trend. The general trend was consistent in 2015 and 2016. In 2016， the yield of plants with shoot??fruit ratio of 1?? 1 was significantly higher than that of 1?? 1.5. There was no significant difference in the yield between the low load treatments with shoot??fruit ratios of 2?? 1 and 3?? 1. For the treatments with high loads， the yields with shoot??fruit ratios of 1?? 2 and 1?? 1.5 in 2016 were slightly reduced from those in 2015 （Table 1）.
Effect of shoot??fruit ratio on fruit quality
The test results showed that the quality of Summer Black grape increased with the decrease of load. The soluble solids in 2015 and 2016 were the highest at the shoot??fruit ratio of 1?? 1， which were significantly higher than those with the shoot??fruit ratios of 1?? 2 and 1?? 1.5， while the content was the lowest with the shoot??fruit ratio of 1?? 2， which was significantly lower than that of the other 5 treatments. In terms of titratable acid content， the treatment with shoot??fruit ratio of 1?? 1.5 was the lowest in both 2015 and 2016， and the highest was found in the treatment with shoot??fruit ratio of 1?? 2 in 2015 and 2016， which was significantly higher than tat of the other treatments. As for solid??acid ratio， the highest was found in the treatment with shoot??fruit ratio of 2?? 1 in 2015 and 1.5?? 1 in 2016， while the lowest was found in the treatment with shoot??fruit ratio of 1?? 2 in both 2015 and 2016. For Vitamin C content， the highest was found with the shoot??fruit ratio of 1?? 1 for the 2 years， which was significantly higher than that of the other treatments. According to the comprehensive performances of all the indicators， the fruit quality was the best with the shoot??fruit ratio of 1?? 1 （Table 2）. Effect of shoot??fruit ratio on grapevine storage nutrient
The test results showed that with the decrease of the load， the storage nutrient indexes of Simmer Black grapevines increased first. The soluble sugar content was the highest at the shoot??fruit ratio of 1?? 1， followed by that of 1.5?? 1， 3?? 1， and it was the lowest in the treatments with shoot??fruit ratio of 1?? 2， 1?? 1.5. In terms of starch content， the highest was found at the shoot??fruit ratio of 3?? 1 for the 2 years， and there was no significant difference between the shoot??fruit ratio of 1?? 1 and 3?? 1 in 2015， both of which were significantly higher than that of the other treatments. In 2015， the free amino acid content was the highest in treatments with shoot??fruit ratios of 3?? 1， 2?? 1 and 1.5?? 1， which showed no significant difference between each other， followed by the treatment with the ratio of 1?? 1. In 2016， the free amino acid content was the highest in treatments with shoot??fruit ratios of 3?? 1 and 2?? 1 and 1.5?? 1， followed by the treatment with the ratio of 1?? 1. In both 2015 and 2016， the content of free amino acid was the lowest in the high load treatments with shoot??fruit ratios of 1?? 2， 1?? 1.5. The soluble protein content was the highest in the treatments with shoot??fruit ratios of 1?? 1 and 3?? 1 for the 2 years， which had no significant difference between each other， followed by the treatments with the ratios of 1.5?? 1， 2?? 1， and the lowest was found with the shoot??fruit ratio of 1?? 2 and 1?? 1.5. According to the comprehensive performances of all the indicators， the grapevine storage nutrient was the highest with the shoot??fruit ratio of 1?? 1 （Table 3）.
Conclusions and Discussion
The load not only affects the yield and fruit quality of the orchard， but also affects the fruit yield in the second year. In order to ensure the high and stable yield of the grapes， and to produce high??quality， high??grade fruit， the production must be strictly controlled[7]. The results of this study show that the yield with shoot??fruit ratio of 1?? 2 is the highest in the 2 consecutive years， followed by that of 1?? 1 and 1?? 1.5. The high load treatments with shoot??fruit ratio of 1?? 2 and 1?? 1.5 have the yield decreased in 2016 from the yield in 2015. High load can seriously deplete the tree nutrients and reduce the storage nutrient， which can weaken the tree growth and reduce the yield in the next year， resulting in unstable yielding[8]. Therefore， it is necessary to carry out flower and fruits thinning in management to reduce the quantity of fruits and the weight of fruit clusters， and thereby making the tree maintain reasonable growth. Soluble solid content plays an important role in grape quality and is the basic raw material for fruit flavor components and other nutrients[9]. In this study， with the increase of tree load， the yield of Summer Black grape increases gradually， but the content of soluble solids， solid??acid ratio and Vitamin C decrease. The reason is that the high load intensifies the competition for nutrients among fruits， decrease the supply of nutrients in each fruit， and thus delay the fruit maturity to some extent[10]. Low??load fruits have higher soluble solid content， which may be due to the fact that the low load reduces the nutrient competition between fruits and enhances the supply of carbohydrates in fruits， thereby increasing the content of sugars and soluble solids[11]. This is consistent with the results of previous studies on varieties such as Summer Black， Red Globe and Jingya[3， 12-14].
The storage nutrient level of the grapevines not only reflects the cold resistance of the tree， but also determines the sprouting rate of new shoots and the quality of the panicles in the next year[15]. A high storage nutrient level of grapevines is more favorable for overwintering and cold resistance. The comprehensive analysis on the soluble sugar， starch， free amino acid and soluble protein content of the grapevines at each shoot??fruit ratio shows that the performance is the best at the shoot??fruit ratio of 1?? 1. The reason why the storage nutrient indexes decrease in the treatments with shoot??fruit ratios of 2?? 1， 1.5?? 1 is that the unbalanced load can affect the nutrient distribution at the "library" end， resulting in vegetative growth and reproductive growth disorders. At high loads， the reproductive growth is too strong， inhibiting the vegetative growth， which not only consumes the storage nutrients of the grapevines， reducing the nutrient accumulation of the tree， but also reduces the fruit quality.
High or low load can affect the formation of grape yield and the development of grape quality. Therefore， determining the optimized load for Summer Black grape can provide a code standard for stabilizing tree nutrients， increasing yield and improving the commerciality of grapes. According to the comprehensive analysis of yield， fruit quality and grapevine storage nutrient， the performance of Summer Black grape is the best at the shoot??fruit ratio of 1?? 1 under the climatic conditions of Tai??an of Shandong Province， when the yield is 1 179.37-1 288.63 kg per 667 m2， followed by the shoot fruit ratio of 1?? 1.5. Zhen HAN et al. Effect of Shoot??Fruit Ratio on Grape Yield， Quality and Storage NutrientReferences
[1] YANG HC， LIU YR， LIN SC， et al. Introduction performances and cultivation techniques of early??maturing triploid seedless grape Summer Black[J]. South China Fruits， 2006， 35（3）： 74-76.
[2] WANG HX， SHEN JS， CHEN YF. High??quality and high??yield cultivation techniques for grape variety Summer Black in Jinhua， Zhejiang[J]. China Fruits， 2010（4）： 45-47.
[3] LI XJ， LI C， ZHAI H， et al. Effects of different loading amounts on fruit quality of Summer Black grape[J]. Shandong Agricultural Sciences， 2015， 47 （8）： 42-45.
[4] LIU XC， CHI LH， LI YX. Test on the fruit loading of "Jingya" grape[J]. Shaanxi Fruits， 2007， 5（3）： 6-7.
[5] LOU HP. Effects of fruit loads on grape quality and vegetative growth[J]. Journal of Liaoning Agricultural College， 2005， 7（1）： 31-32.
[6] ZHAO SJ， SHI GA， DONG XC. Plant physiology experiment guide[M]. Beijing： China Agricultural Science and Technology Press， 2002.
[7] MAO AN， LIU Q. Study on the relationship between yield and quality traits and load of Kyoho grape in South China[J]. Journal of Fruit Science， 1994， 11（2）： 76-80.
[8] SHI XB， SUN YJ， GAO RG， et al. Effects of rate of fertilizer application and load on yield， quality and nutrient storage of Kyoho grape[J]. Journal of Agricultural University of Hebei， 2012， 35（6）： 12-17.
[9] GUO L， CHEN JL， SONG CN， et al. Effects of girdling time on berry qualities and coloring of Fujiminori??s berry in greenhouse[J]. Sino??Overseas Grapevine and Wine， 2011 （11）： 10-14.
[10] NAOR A， GAL Y， BRAVDO B. Shoot and cluster thinning influence vegetative growth， fruit yield， and wine quality of ??Sauvignon blanc?? grapevines[J]. Journal of American Society for Horticultural Science， 2002， 127（4）： 628-634.
[11] PRAJITNA A， DAMI IE， STEINER TE， et al. Influence of cluster thinning on phenolic composition， resveratrol， and antioxidant capacity in Chambourcin wine[J]. American Journal of Enology and Viticulture， 2007， 58（3）： 346-350.
[12] ZHAO WD， MAN LT， SUN LL， et al. Effect of different trellises and fruit loads on berry quality of grapevine cv. Red Globe[J]. Sino??Overseas Grapevine and Wine， 2010 （11）： 20-22.
[13] DAI ZX， CHEN LR， LIU Q. Effect of the load of Fujiminori grape on fruit development and tree growth[J]. South China Fruits， 1997， 26（3）： 46-47.
[14] LU MD， HE K， PEI QS， et al. Effects of different fruit loads on berry maturity and quality in grape cultivar Yinhong[J]. Journal of Zhejiang University （Agriculture & Life Sciences， 2014， 40（2）： 175-180.
[15] ZHENG XC， WANG HB， WANG XD， et al. Evaluation of cold resistance of 14 grape rootstock varieties[J]. China Fruits， 2014（1）： 36-39.