INFLUENCE OF GA3 AND DIFFERENT 6-BENZYLAMINOPURINE DOSES ON FRUIT QUALITY OF SUPERIOR SEEDLESS GRAPEVINES.

CONCLUSION

From the present study, it is suggested that the application of GA₃ 20 mg/L in combination with BAP at 5 mg/L significantly enhanced the yield and the grape quality attributes such as, cluster weight, berry size, berry dimensions, berry firmness, the free total amino acids and the total phenols. However, it caused slight effects on the T.S.S, T.S.S /acidity ratio and total sugars. Eventually, it is recommended to be applied as GA₃at 20 mg/L with BAP at 5mg/L at a mean berry diameter of about 8-10 mm for improving the berry quality of Superior grapevines.

INFLUENCE OF GA₃ AND DIFFERENT 6-BENZYLAMINOPURINE DOSES ON FRUIT QUALITY OF SUPERIOR SEEDLESS GRAPEVINES.

Mekawy, A.Y. and A.S.S. Ahmed

Viticulture Dept. Hort. Res. Instit. ARC, Giza, Egypt.

Key Words: 6-benzylaminopurine (BAP), gibberellin (GA₃), grapevine, plant growth regulator, Superior Seedless.

ABSTRACT

This study was carried out during the two successive seasons 2016 and 2017 to examine the effect of single or combined applications of 6-benzylaminopurine (BAP) at 2.5 or 5 mg/L and gibberellin (GA₃) at 20 mg/L on yield and berries quality in Superior grapevines. The results illustrate that dipping clusters with BAP alone or combined with GA_3, at an average berry diameter of 8-10 mm, improved yield, berry quality characteristic such as firmness, total free amino acids, total phenols, total sugars, T.S.S. % and decrease total acidity %, comparing with the control treatment. The best results with regard to quality of Superior berries were obtained with using GA₃ at 20 mg/L with BAP at 5 mg/L in all parameters.

INTRODUCTION

Superior Seedless grape (Vitis vinifera L.) is considered as one of the most important table grape varieties, since its grapes are desired for export to the international markets. As, small berry size represents a problem of table grape growers, the key of improving the quality of Egyptian grapes exported to the international markets is optimizing the berry quality including physical and chemical characteristics of the berry.Berry size is the main quality factor in international markets as affected by many things like hormones, nutrients and environmental factors (Ollat et al. 2002). 

As already pointed out, plant hormones have been generally used in viticulture to enhance chemical and morphological characteristics of clusters and berries of grapes, making it the most economically important (Vieira et al., 2008 and Bhat et al., 2011). Moreover, Ravest et al., (2017) mentioned that gibberellins are a group of plant growth regulators that promote cell division and elongation in different plant organs and are participate in numerous developmental processes, for instance berry development, it is well known to improve the size and quality of berries. In addition, Jauregui et al., (2017) suggested that the use of plant hormones can provide significant economic advantages to grape growers when applied to appropriate situations as these have proven effectiveness as stimulating the number of required responses such as increase in fruit size.

GA₃ applications are usually done either by spraying or by dipping clusters in a GA₃ solution, with the latter technique being very labour intensive. The manual dipping technique is specifically used because it is believed the decreased fertility associated with GA₃ spray applications can be prevented (Abu-Zahra and Salameh, 2012).Indeed, exogenous application of cytokinins including 6-benzylaminopurine, has been largely applied in horticultural crops for instance grape, kiwifruit and apple to enhance fruit set and/or maximizes fruit size (Stern et al., 2003; Kim et al., 2006 and Zabadal, 2006). BAP (6-Benzyladenine or 6-Benzylaminopurine) is N6-substituted adenine derivatives, representing aromatic cytokinins, have been discovered in a many of plant species as minor components of the total cytokinins, as described by Strnad, (1997) and Saenz et al., (2003). Interestingly, a short survey of 38 countries indicates that 6-Benzylaminopurine is used in 63 % many more countries than in 6-Benzyladenine (Teixeira, 2012).

The objective of this study, as there is a shortage of studies on the application of gibberellin with 6-benzylaminopurine as proposed by Souza et al., (2010), is to evaluate the effects of 6-benzylaminopurine, gibberellin alone or combined, on levels of improving fruit quality of grapevine cv. Superior Seedless.

MATERIALS AND METHODS

This study was conducted during two consecutive seasons of 2016 and 2017 in a commercial vineyard located at Minia Governorate, Egypt. Eight-year-old Superior seedless grapevines (Vitis vinifera L.), growing in silty clay soil under surface irrigation system were used in this investigation. Fifty-four vines (6 treatments x 3 replicates x 3 vines / replicate) trained to cane pruning under gable system, and spaced to 1.5 x 3 m, the selected vines received the usual horticultural operations that are used in the vineyard.

BAP and GA₃ were applied by dipping clusters once in the solution using a wide-mouthed container at once when averages diameter of the berries reached about 8-10 mm. Triton B as a wetting agent was added to all solutions as follow:

1- Control (dipped in water only).

2- GA₃at 20 mgL^-1

3- BAP at 2.5 mgL^-1

4- BAP at 5 mgL^-1

5- BAP at 2.5 mgL^-1 + GA₃ at 20 mgL^-1

6- BAP at 5 mgL^-1 + GA₃ at 20 mgL^-1

Clusters were harvested on the first week of June in both seasons. All vines were representative random samples were collected when total soluble solids reached about 16% according to Badr and Ramming (1994), transported to the laboratory to determine quality parameters as physical and chemical characteristics:

1. Yield and physical characteristics of clusters:

1.1 Yield (kg)

1.2 Cluster weight (g)

1.3 Cluster dimensions (cm)

1.4 Berry weight (g)

1.5 Berry size (cm³): the berry volume was determined according to Hidnert and Peffer, (1950).

1.6 Berry dimensions (cm).

1.7 Berry firmness (g/cm²): It was determined using Penetrometer, Model FT 011, Italy.

1. 2.    Chemical characteristics of berries:

2.1 Total sugars (%) were determined by using the 3, 5 dinitrosalicylic acid method (Miller, 1959).

2.2  Refractometric total soluble solids (T.S.S. %), titratable acidity as gram of tartaric acid per 100 ml of juice (A.O.A.C., 1985) and T.S.S. / acid ratio.

2.3 Total phenols (%) content were determined according to the Folin-Ciocalteu colorimetric method (Singleton and Rossi, 1965).

2.4 Total free amino acids (g/100 mg) were determined according to Jayaraman, (1985).

1. The economic study:

The economic evaluation of spraying GA₃ at 20 mg/L and different doses of 6-Benzylaminopurine to improve fruit quality of grapevine cv. Superior Seedless was calculated for the average of the two seasons for the various items, regarding the cost per feddan for each.

1. Experimental design and statistical analysis:

The experimental design was a randomized complete block design (RCBD). The collected data were tabulated and statistically analyzed as described by Snedecor and Cochran (1980) for comparing the differences between treatments by using the new L.S.D. test.

RESULTS AND DISCUSSIONS

1. Morphological measurements:

1.1 Yield (kg)

   As shown in Table 1 and figure 1, yield /vine was significantly increased by the application with GA₃ and different rates of BAP either in the single or in the combined treatments compared with control in both seasons. Treatment  with   GA₃ and the highest dose of BAP at 5 mg/L  resulted in the highest values (13.1 and 13.2 Kg/vine) for both seasons respectively, whereas; the lowest values were obtained from control vines (6.5 and 6.7 Kg/vine) for both seasons respectively.  The results obtained under the present investigation are also supported with the findings of (Chaitakhob et al., 2014; Kumar and Sharma, 2016). Increased yield is positively related to the berry weight and thus the cluster weight and may also be related with proper nutritional supply to the developing clusters associated with higher photosynthetic capacity, translocation of photosynthates to the treated clusters with the GA₃ and BAP (Huang et al., 2002)

Table 1: Effect of treatment with GA3 & 6-BAP on yield and physical characteristics of clusters in Superior Seedless grapevine during 2016 and 2017 seasons.

1.2 Cluster weight (g)

Data in Table (1) revealed the application of GA₃ + BAP 5 mg/L had the highest cluster weight (546.5 and 551.7 g) in two growing seasons, whereas, the lowest weight (272.4 and 280.7 g) was recorded in control, in two growing seasons, respectively. As mentioned by Huang et al., (2002) increased cluster weight is ascribed to the proper nutritional supply received by the vines treated with GA₃ and BAP which associated with higher photosynthetic capacity.

1.3 Cluster dimensions (cm)

Statistical analysis did not show any significant differences in Table (1) between width and length of clusters treated with GA₃ and BAP 5 mg/L compared to the control in both seasons.  These results coincide with the findings of Chaitakhob et al., 2014.

1.4 Berry weight (g)

It is clear in Table 2 and figure 2 that the clusters dipped with the lower concentration of (BAP 2.5 mg/L) in combination with GA₃ were characterized by lower berry weight than the higher dose of 5 mg/L BAP in combination with GA₃ in both seasons. However, it enhanced the berry weight values (6.63 g) in the first season, and (6.87 g) in the second compared to control (2.80 g and 2.65 g) respectively. In the previous studies of Casanova et al. (2009) reported that the application of gibberellic acid in seedless varieties at the initial stage of cell growth increased berry weight and reached to similar values as in seeded varieties. Moreover, the observed increase in the berry weight treated with the BAP in combination with GA₃ may be due to greater mobilization of photoassimilates to the clusters. These results was previously concluded by Stern et al., (2007) who ascribed the role of BAP in improving fruit weight to its role in increasing cell division during the early stages of fruit development.

Table 2: Effect of treatment with GA3 & 6-BAP on Physical characters of berries in Superior Seedless grapevine during 2016 and 2017 seasons.

1.5 Berry size (cm³)

It was evident from Table (2), that all the treatments are significantly increased the berry size in two growing seasons compared to control. Data revealed that the application of GA₃and the mixture of GA₃+ BAP at (5 mg/L) had a beneficial influence on the berry size with superiority when compared to other treatment and control respectively.GA₃ is also reported to promote growth by increasing plasticity of the cell wall followed by the hydrolysis of starch into sugars which reduces the cell water potential, resulting in the entry of water into the cell and causing elongation (Richard, 2006).The direct effect of GA₃on stimulating cell division and cell enlargement and increasing fruit size was previously indicated by Valero, (2010). In addition, (Shiozaki et al., 2014) reported that BAP stimulated the berry development by increasing the levels of free polyamines in the grape berry. Cell elongation and cell division to the clusters treated by both with GA₃ and BAP was accompanied by an inevitable increase in berry size. Present results are in conformity with the findings of Chaitakhob et al.,(2014) who recommended  that using of the cluster dipping with BAP+ GA₃ instead of GA₃alone in different grape cultivars, has a greater effect on increasing the berry size.

1.6 Berry dimensions (cm)

It is clear from the data in table (2) that all the treatments are significantly increased the berry dimensions in the two growing seasons compared to control. The higher results were obtained from the application of GA₃ and the mixture of GA₃ + BAP at (5 mg/L). The promotion of the berry length and width by GA₃ treatment may be due to its role in increasing cell enlargement as described by Pharis and King, (1995). While the mechanism of the BAP in enhancing the berry length and width may be due to its role in increasing cell division during the early stages of berry development (Stern et al., 2007).

1.5 Berry firmness (g/cm²)

         The positive effects attributed to dipping clusters in GA₃ and different rates of BAP either in the single or in the combined form were obvious on the berry firmness (Table, 2). Using of the BAP at (5 mg/L) in combination with GA₃ enhanced the berry firmness values in both seasons compared to control. The present findings are in accordance with those reported by Souza et al.,(2010) and El-Abbasy et al.,(2015).

A synthetic cytokinin, applied after fruit set increases the firmness of table grapes (Vitis vinifera L.) (Peppi and Fidelibus, 2008), beyond what is possible without treatment of BAP. Rizk-Alla et al.,(2011) reported that spraying GA₃after fruit set improved the number of epidermis and hypodermal layers in berry skin and increasing the diameter, thickness of bark and diameter of wood cylinder of the berry pedicel, resulting in the grape berry firmness. Additionally,   Jian-Na, (2012) mentioned that the application of BAP was delayed the deterioration of membrane permeability of the grape berry, resulted in the maintained firmness of the berry. Eventually, applications of GA₃ reduced the activities of polygalacturonase and pectin methyl esterase enzymes and improved fruit firmness (Canli, 2014).Additionally, El-Abbasy et al.,(2015)  reported that the increasing in the berry firmness is attributing to increased cell turgidity as sugar and potassium are downloaded in the berries, stimulating water uptake driven by osmotic pressure of the berries.

2-Chemical characteristics of berries:

2.1 Total sugars (%)

          Data in Table (3) obviously showed that total sugars  (%) were significantly increased by the combined application of GA₃ and the highest dose of BAP at 5 mg/L. These results were confirmed by those obtained from Kiran et al., (2019) who revealed that maximum berry juice content of total sugars was recorded in the grapes treated with gibberellic acid treatment as cluster dipping. However, the combination of GA₃and 6-BAP enhances the endogenous hormone levels such as  ABA (Juan et al.,2009), which in turn increases the  total sugars in berries of Red globe grapevines (Mekawy and Ahmed, 2018).

2.2 Total soluble solids (T.S.S. %), titratable acidity and T.S.S. / acid ratio

          Data in Table (3) showed the inconsistent response of soluble solids and titratable acidity in all treatments with a higher content of T.S.S.% in the sixth treatment (BAP at 5 mg/L + GA₃).This is confirmed by the study of Singh et al., (1993) who reported that this increase of T.S.S. due to application of gibberellic acid is attributed to accumulation of more carbohydrates. The possible reason for improvement in the amount of T.S.S. content could be due to increased capacity of the grape berries to draw more carbohydrates through increased amount of auxin content directly or indirectly by quicker metabolic transformation of soluble compounds induced by the gibberellic acid. However, Cytokinin has been shown to play a major role in the regulation of various processes associated with active growth and thus an enhanced demand for carbohydrates (Chaitakhob et al., 2014).

In the treatments with BAP 5 mg/L combined with GA₃ decreased acidity, causing an increase in T.S.S/acid ratio (Table 3), results also reported by Souza et al., (2010) and Guerios, et al., (2016)  with 'Superior Seedless' grapevines.

2.3 Total phenols (%)

   Applying of the above mentioned treatments causing an increase in the total phenols values compared to control (Table, 3). Higher results were obtained from the combined application of GA₃ along with the higher dose of BAP at 5 mg/L. The role of GA₃ and BAP may be related with proper nutritional supply to the developing clusters associated with higher photosynthetic capacity, translocation of photosynthates to the clusters (Huang et al., 2002), and may increase the total phenols in ‘Superior Seedless’ grape berry. 

2.4 Total free amino acids (g/100mg)

Applying the plant hormones demonstrated a beneficial effect on the total free amino acidsin ‘Superior Seedless’ grape (Table 3 and figure 3). It was found that clusters treated with GA₃ and the mixture of GA₃ + 5 mg/L BA had significantly increased total free amino acids contents in the grape berry than the control. Interestingly, Shiozaki et al,(2014) reported that the polyamines levels are generally strongly correlated with cell division in plants. Huang et al., (2002) mentioned that proper nutritional, higher photosynthetic capacity and translocation of photosynthates to the clusters which increased the total free amino acids in ‘Superior Seedless’ grape berry are related to the role of GA₃ and BAP.

Table 3: Effect of treatment with GA3 & 6-BAP on chemical characteristics in berry juice of Superior Seedless grapevine during 2016 and 2017 seasons.

3. The economic study:

Table (4) showed the economic justification of the recommended treatment (spraying with GA 20 mg/L + BAP 5  mg/L) compared with the other treatments. It can be shown from the data presented that it gave the maximum net profit in both seasons. From the obtained results, it can be concluded that clusters treated with dipping GA₃ 20 mg/L + BAP 5 mg/L gave the highest yield and improved the physical and chemical characteristics of berries.

Moreover, the cost of production /feddan over control for this treatment is economically justified in view of the higher price of the yield obtained from this treatment.

Table (4) The economic study of the cost per feddan for each treatment of Superior Seedless as average for two seasons (2016 and 2017)

CONCLUSION

From the present study, it is suggested that the application of GA₃ 20 mg/L in combination with BAP at 5 mg/L significantly enhanced the yield and the grape quality attributes such as, cluster weight, berry size, berry dimensions, berry firmness, the free total amino acids and the total phenols. However, it caused slight effects on the T.S.S, T.S.S /acidity ratio and total sugars. Eventually, it is recommended to be applied as GA₃at 20 mg/L with BAP at 5mg/L at a mean berry diameter of about 8-10 mm for improving the berry quality of Superior grapevines.

REFERENCES

Abu-Zahra, T.R. and  N.M. Salameh, ( 2012). Influence of gibberellic acid and cane girdling on berry size of Black Magic grape cultivar. Middle-East J. Sci. Res., 11(6): 718 –722.

A.O.A.C., (1985). Association of Official Agricultural Chemists. Official  Methods of Analysis .9th ed., Benjamin.Franklin Station, Washington , D.C.,P.O.Box. 450, 832 pp.

Badr, S.A. and D.W. Ramming (1994). The development and response of Crimson Seedless cultivar to cultural practices. International Symposium on Table Grape Production, 219-222.

Bhat,  Z.A.; Y.N. Reddy; D. Srihari; J.A. Bhat; R. Rashid and J.A. Rather (2011). New   generation growth regulators brassinosteroids and CPPU improve bunch and berry characteristics in ‘Tas-A-Ganesh’ grape. Int. J. Fruit Sci., 11(4): 309 –315.

Canli, F.A.; M. Sahin; N. Temurtas and M. Pektas (2014). Improving fruit quality of apricot by means of preharvest benzyladenine and benzyladenine plus gibberellin applications. Hort. Technology, 24 (4):424 - 427.

Casanova, L.; R. Casanova; A. Moret and M. Agusti (2009). The application of gibberellic acid increases berry size of ‘Emperatriz’ Seedless grape. Spanish Journal of Agricultural Research, 7(4): 919-927.

Chaitakhob,  N.; B. Janchean; N. Pilap and S. Methaneekornchai, (2014). Influence of gibberellic acid and n6-benzyladenine on the development of seed and berry quality in 'Perlette' Seedless grape . Acta. Hortic., 1024:197-203.

El-Abbasy, U. K.; S. M. Al-Morsi; F.E. Ibrahim and  M.H. Abd El-Aziez (2015). Effect of gibberellic acid, cytofex, and calcium chloride as pre-harvest applications on storability of “Thompson Seedless” grapes Egypt. J. Hort., 1(42):427-440.

Guerios, I.T.; F. Chiarotti; F.L. Cuquel and L.A. Biasi (2016). Growth regulators improve bunch and berry characteristics in 'Niagara Rosada' grape. Acta. Hortic., 1115: 243-248.

Hidnert, P. and E.L. Peffer (1950). Density of solids and liquids,Natl. Bur. Standards circ. 487, 28p. 

Huang, W.D.; P. Zhangand W.Q. Li (2002). The effects of 6-BA on the fruit development and transportation of carbon and nitrogen assimilates in grape. Acta Horticulturae Sinica., 29(4): 303-306.

Jauregui, F.R.; K.M. Soledad; J.A. Alcalde and D. Perez (2017). CPPU treatment modifies quality and susceptibility to post-harvest berry cracking of Vitis vinifera cv. ‘Thompson Seedless. J. Plant Growth Regul., 36(2):413-423.

Jayaraman, J. (1985). Post Harvest Biological Control. Wiley Eastern Limited, New Delhi

Jian-Na, Y; R. Xiao-Lin; C. Bai; Y. Yan-Qing and L. Shu-Gangl (2012). Effect of preharvest 6-benzyladenine treatment on quality and physiology of table grapes during cold storage. Plant Physiology Journal, 48 (7): 714-720.

Juan, H.; Y. Songlin and M. Chao (2009). Effects of plant growth regulator on endogenous hormone levels during the period of the Red Globe Growth.Journal of Agricultural Science,1(1): 92-100.

Kim,  J.G.; Y. Takami,; T. Mizugami; K.Beppu; T. Fukuda and  I. Kataoka (2006). CPPU application on size and quality of hardy Kiwifruit. Sci Hortic., 110(2):219–222.

Kiran, S. D.C.; S.I. Athani; J.B. Gopali; D.R. Patil; H.R. Manukumar and K.M. Shivakumar (2019). Effect of gibberellic acid on berry quality parameters of different grape varieties under northern dry zone of Karnataka. International Journal of Chemical Studies, 7(1): 759-762.

Kumar, K.T. and M.K. Sharma (2016). Effect of GA₃ in combination with urea phosphate and BA on yield and physical quality parameters of grape cv. Thompson Seedless. The bioscan, 11(1): 49-52.

Mekawy, A.Y. and A.S.S. Ahmed (2018). Effect of abscisic acid and green tea extract on fruit quality of ‘Red Globe’grapevines. Middle East J. Appl. Sci., 8(4): 1325-2334.

Miller, G.L. (1959). Use of dinitrosalicylic acid reagent for determination of reducing sugars.Anal chem., 31:426-428.

Ollat, N.; P. Diakou-Verdin; J.P. Carde; F.Bar–Rieu; J.P. Gaudillere and A. Moing (2002). Grape berry development: a review. J. Int. Sci. Vigne. Vin., 36: 109-131.

Peppi, M.C. and M.W. Fidelibus (2008). Effects of forchlorfenuron and abscisic acid on the quality of ‘Flame Seedless’grapes. Hortscience, 43(1):173–176.

Pharis,  R.P.  and  R.W.  King (1985). Gibberellic and reproductive development in seed plants. Ann. Rev. Plant Physiol., 36: 517-568.

Ravest, G.; S. Silva; M. Mamani; J. Correa; C. Muñoz; M. Pinto; L. Giacomelli; C. Moser and P. Hinrichsen (2017). Expression analysis of gibberellin metabolism genes and metabolites during berry development in table grape. Acta Hortic., 1157: 131-136.

Richard, M. (2006). How to grow big peaches. Dep. of Hort. Virginia Tech. Blacksburg, VA 24061.Internet, www.Rce.rutgers.edu. 8 p.

Rizk-Alla, M.S.; M.A. Abd El-Wahab and O.M. Fekry (2011). Application of GA3 and NAA as a means for improving yield, fruit quality and storability of Black Monukka grape Cv. Nature and Sci., 9 (1):1-19.

Saenz, L.; L.H. Jones; C. Oropeza; D. Vlacil and M. Strnad (2003).  Endogenousisoprenoid  and  aromatic  cytokinins  in  different  plant  parts  of Cocosnucifera (L.). Plant Growth Regul, 39:205–215.

Shiozaki, S.; R. Sakurai; M. Hotta and T. Ogata (2014). Effects of BA and CPPU on polyamine content, setting and development of Seedless grapes induced by gibberellins.The Journal of Animal & Plant Sciences, 24(2):967-972.

Singh, S.; I.S. Singh and D.N. Singh (1993). Physico-chemical  changes  during  development  of  Seedless grapes (Vitis vinifera L.). Orissa J. of Horticulture, 21: 43-46.

Singleton, V.L. and J.A. Rossi, (1965): Colourimetry of total phenolics with phosphomolibdic phosphotungstic acid reagent. American Journal of Enology and Viticulture, 16: 144-158.

Snedecor, G. W. and W.G. Cochran, (1980). Statistical Methods. 7th ed., The Iowa State Univ. Press. Ames. , Iowa, U.S.A., pp. 593.

Souza, E.R.; M.C. Pereira; L.S. Santos; V.G. Ribeiro; J.A.A. Pionorio and E.A. Araujo (2010). Quality of grapes ‘Superior Seedless’ with benzyladenine combined with applications or not of gibberellic acid. Revista Caatinga, Mossoro, 23(4): 144-148.

Stern, A.R.; R. Ben-Arie; O. Neria and  M. Flaishman ( 2003). CPPU and BA increase fruit size of ‘Royal Gala’ (Malus domestica) apple in a warm climate. Journal of Horticultural Science and Biotechnology.,78(3):297–302.

Stern, A.R.; I. Doron and R. Ben-Arie (2007). Plant growth regulators increase the fruit size of ‘Spadona’ and ‘Coscia’ pears Pyrus communis in a warm climate. J. Hort. Sci. Biotechnol., 82:3-7.

Strnad, M. (1997). The aromatic cytokinins. Physiol Plant,101:674–688.

Teixeira da Silva, J. (2012). Is BA (6-benzyladenine) BAP (6-benzylaminopurine) ?. The Asian and Australasian Journal of Plant Science and Biotechnology, 6: 121-124.

Valero, D. (2010). Influence of postharvest treatment with putrescine and calcium on endogenous polyamines, firmness, and abscisic acid in lemon (Citrus lemon L Burm cv. Verna). J. Agric.Food Chem., 46: 2102–2109.

Vieira, C.R.Y.I.; E.J.P. Pires; M.M. Terra; M.A. Tecchio and R.V. Botelho (2008). Effects of thidiazuron and gibberellic acid on cluster and berries characteristics of‘Niagara osada’ grape. Review Brasileira de Fruticultura, Jaboticabal, 30(1):12-19.

Zabadal, T.J. and  M.J. Bukovac (2006). Effect of CPPU on fruit development of selected Seedless and Seeded grape cultivars. Hort Sci., 41:154-157.

تأثیر الجبرلین ومعدلات مختلفة من 6 بنزیل أمینو بیورین على جودة کرمات العنب السوبیریور

أحمد یسین مکاوی حسن  –عبدالجواد صبحى شعبان أحمد

معهد بحوث البساتین – مرکزالبحوث الزراعیة – الجیزة – مصر.

أجریت هذه التجربة خلال عامین متتالین 2016 و 2017 لدراسة تأثیر المعاملات المنفردة والمخلوطة  من 6- بنزیل أمینو بیورین عند ترکیز 2.5 أو 5 ملجم / لتر و الجبرلین عند ترکیز 20 ملجم / لتر على المحصول وجودة الثمار لکرمات العنب السوبریور.

أوضحت النتائج أن غمس العناقید فى محلول بنزیل أمینو بیورین بمفرده أو بالإضافة إلى  الجبرلین عند وصول قطر الحبة من 8 - 10 مم أدى إلى تحسین المحصول ، صفات جودة الحبات ، الصلابة ، الأحماض الأمینیة الحرة ، الفینولات الکلیة ، السکریات الکلیة والمواد الصلبة الذائبة الکلیة مع تقلیل الحموضة الکلیة مقارنة بالکنترول. وکانت أفضل النتائج بالنسبة لجودة حبات العنب السوبیریور قد تحصل علیها بالمعاملة بالجبرلین بترکیز 20 ملجم /لتر مع 6- بنزیل أمینو بیورین بترکیز 5 ملجم / لتر فى جمیع القیاسات.