Effect of grafting on the tomato's yield, quality - Akademiai.com

Acta Alimentaria, Vol. 34 (4), pp. 453–462 (2005) 

EFFECT OF GRAFTING ON THE TOMATO’S YIELD, QUALITY 

AND MAIN FRUIT COMPONENTS IN SPRING FORCING 

Á. POGONYI a , Z. PÉK a , L. HELYES a and A. LUGASI b * 

a Department <strong>of</strong> Horticulture and Technology, Szent István University, 

H-2103 Gödöll , Páter K. út 1. Hungary 

b National Institute for Food Safety and Nutrition, H-1097 Budapest, Gyáli út 3/a. Hungary 

(Received: 9 December 2004; accepted: 31 August 2005) 

Soil-born diseases <strong>of</strong>ten cause problems in vegetable forcing; this is because growers use greenhouses 

for the longest time possible. During the years several solutions have been found to displace chemical 

control. Grafting is a possible chemical free solution that shows several changes in plants thanks to the 

vigorous rootstock. In this study we examined the effect <strong>of</strong> <strong>grafting</strong> on the yield and fruit characteristics 

in tomato cultivar. Lemance F 1 was used as scion and Beaufort as rootstock. Earliness, total yield, fruit 

weight and number <strong>of</strong> each graft combination were recorded. Moreover, the main fruit components 

such as Brix°, carbohydrate, acid and the carbohydrate/acid ratio were analysed. We harvested more 

yield from the grafted plants. The increase <strong>of</strong> yield was mainly caused by higher average fruit weight. 

Brix° and carbohydrate content were lower in the fruits on grafted plants than on ungrafted ones but 

there was no significant difference in acid content. 

Keywords: acid, Brix°, carbohydrate, <strong>grafting</strong>, quality, tomato 

Use <strong>of</strong> grafted seedlings has become a widespread practise in many parts <strong>of</strong> the world. 

One <strong>of</strong> the advantages <strong>of</strong> using grafted plants is the resistance or tolerance to the soilborn 

diseases (corky root, fusarium wilt, verticillum wilt, bacterial wilt) and nematodes, 

which cause most <strong>of</strong> the damages to continuous cropping in greenhouses (ODA, 1999; 

LEE & ODA, 2003). This was the early purpose <strong>of</strong> using grafted seedlings, but there are 

several other reasons <strong>of</strong> <strong>grafting</strong> (LEE, 1994). Due to the utilization <strong>of</strong> vigorous root 

system <strong>of</strong> the rootstocks, grafted plants usually show increased uptake <strong>of</strong> water and 

minerals compared to self-rooted plants. There are several other advantages <strong>of</strong> <strong>grafting</strong> 

such as low and high temperature tolerance, salt tolerance, extended harvest period, 

earliness and increase <strong>of</strong> yield (LEE & ODA, 2003). Tomato is a major vegetable where 

<strong>grafting</strong> is important worldwide, although <strong>grafting</strong> is also <strong>of</strong>ten used in case <strong>of</strong> 

watermelon, cucumber, melon, eggplant and capsicum pepper (LEE, 2003). 

Tomato contains about 93–96% water. The total soluble solids range from 4% to 

9% (ADAMS, 1986). The content <strong>of</strong> total soluble solids is inversely related to fruit 

yield (STEVENS & RUDICH, 1978). Sugars, mainly glucose and fructose, account for 

about half <strong>of</strong> the dry matter or 65% <strong>of</strong> the soluble solids <strong>of</strong> a ripe tomato fruit. 

* To whom correspondence should be addressed. 

Phone: +36-1-476-6461; fax: +36-1-215-5369, e-mail: lugasi@oeti.antsz.hu 

0139-3006/$ 20.00 2005 Akadémiai Kiadó, Budapest

454 POGONYI et al.: EFFECT OF GRAFTING ON TOMATO QUALITY 

The sugar content ranges from 1.7 to 4.0% <strong>of</strong> fruit fresh weight. The organic acids in a 

tomato fruit consist mainly <strong>of</strong> citric and malic acid. The acid content ranges from 0.3– 

0.6% (HELYES, 1999). 

Sugars, acids and their interactions are important in relation to sweetness, sourness, 

and flavour intensity in tomatoes. Much sugar and relatively high concentration <strong>of</strong> acids 

are required for the best flavour. High concentration <strong>of</strong> acids and low sugar content will 

produce a tart tomato, while high sugar content and low concentration <strong>of</strong> acids will 

result in a bland taste. When both sugar and acid contents are low, the result is a 

tasteless, insipid tomato. It is supposed the best if the ratio <strong>of</strong> sugar to acid ranges from 

9 to 10 (HELYES, 1999). 

Numerous rootstocks were developed, which have quite different characteristics 

and resistance (LEE, 1994). For example, eggplants were commonly used as rootstocks 

for tomato in earlier years (LEE & ODA, 2003). 

ODA and co-workers (1996) examined the effect <strong>of</strong> scarlet eggplant rootstock on 

growth, yield and sugar content <strong>of</strong> grafted tomato. Fruit yield on scarlet eggplant 

rootstock was lower than that on tomato rootstocks. Soluble solids and sugar contents in 

fruit were all higher in plants grafted on scarlet eggplant than those on tomato 

rootstocks. 

ROMANO and PARATORE (2001) studied the consequences <strong>of</strong> <strong>grafting</strong> on fruit 

production and characteristics <strong>of</strong> tomato on three different rootstocks (one <strong>of</strong> them was 

the Beaufort that we also investigated). The use <strong>of</strong> Beaufort enhanced the growth and 

production, but resulted in a minimum Brix°. In their trial Brix° <strong>of</strong> ungrafted fruits was 

the highest. 

CHUNG and co-workers (1997) examined the differences in marketable yield and 

fruit components between grafted and non-grafted tomato plant. Grafting increased the 

number <strong>of</strong> marketable fruits, although soluble solids, ascorbic acid and total soluble 

sugar content were higher in ungrafted plants than those in grafted ones. 

In this study we investigated the effect <strong>of</strong> <strong>grafting</strong> on yield, quality and 

concentration <strong>of</strong> the main components in tomato fruits such as soluble solids (Brix°), 

carbohydrate, organic acid and the ratio <strong>of</strong> carbohydrate and acid, as well. 

1.1. Plant material 

Acta Alimentaria 34, 2005 

1. Materials and methods 

The experiments were conducted in the test sites <strong>of</strong> Szent István University, Gödöll in 

a spring greenhouse forcing in 2002. Tomato variety Lemance F 1 as scion was grafted 

to Beaufort rootstock <strong>of</strong> different ages. Grafted and ungrafted seedlings were planted at 

two different times. The main parameters <strong>of</strong> tomato plant introduction can be seen in 

Table 1.

POGONYI et al.: EFFECT OF GRAFTING ON TOMATO QUALITY 455 

Table 1. The main parameters <strong>of</strong> tomato plant introduction 

Action Date 

Sowing <strong>of</strong> Beaufort 17. 01. 

Sowing <strong>of</strong> Beaufort 21. 01. 

Sowing <strong>of</strong> Beaufort and Lemance F1 25. 01. 

Grafting period 28. 02. – 04. 03. 

Planting out <strong>of</strong> Lemance F1 13. 03. 

Planting out <strong>of</strong> grafted plants 25. 03. 

First harvest 27. 05. 

Last harvest 05. 08. 

The plant density was 2.1 plants m –2 . The distance between the rows was 1.2 m 

and the distance between the plants was 0.4 m in the rows. Plants were arranged in four 

repetitions and two plants per replicate were randomly selected for detailed 

examination. Flowering and fruit development was checked separately on the first eight 

trusses on the marked plants. Growing techniques followed the common practice 

suggested for greenhouse tomatoes. Plants were cultivated on soil, irrigated with a 

standard nutrient solution by means <strong>of</strong> a drip irrigation system, plant trained to one 

stem, supported by a high wire system. During the experiment the number and weight 

<strong>of</strong> fruits on each truss were recorded. At every harvesting date, fruits were classed by 

quality and size according to CODEX ALIMENTARIUS HUNGARICUS (1995). We 

distinguished five quality classes (extra, first, second, third class and unmarketable) and 

seven size categories (1: 35–40; 2: 40–47; 3: 47–57; 4: 57–67; 5: 67–82; 6: 82–102; 7: 

>102 mm in diameter) in extra and first class. Fruit samples were harvested three times 

during the vegetation period (June 18 and 25, July 9) for chemical analysis. 

Temperature was determined by the SKY micrometeorological equipment. The 

instrument measured the temperature six times per hour and calculated an average. 

1.2. Chemical analyses 

Fruits from each repetition were washed, cut and mixed and the juice samples were 

refrigerated at –18 °C until analysis. The Brix° was examined with refractometer (AST 

1230, Japan) according to HUNGARIAN STANDARD (1998). Acid content <strong>of</strong> fruits was 

determined according to HUNGARIAN STANDARD (1993) and expressed as g citric acid 

in 100 g or kg fresh weight. Carbohydrate content was measured after an acidic 

hydrolysis with HCl at 65 °C during 5 min by the modified Schoorl-Regenbogen 

method (HUNGARIAN STANDARD, 1986). 

1.3. Statistics 

Statistical analyses were done with the use <strong>of</strong> ANOVA program. Each point in tables 

and figures represents the mean ±SD <strong>of</strong> two replicate analyses. Data indicated are 

significantly different at P



2. Results and discussion 

To obtain comparable data from different planting times the accumulated yield was 

examined in relation to the sum <strong>of</strong> effective temperature (above 10 °C) calculated from 

the planting date (Table 1). Figure 1 shows the relationship between the sum <strong>of</strong> 

effective temperature and the accumulated yield quantity. This suggests that grafted 

plants need higher heat sum up to the first harvest. The ungrafted and grafted plants 

accumulated about 800 °C and 840 °C, respectively, between the planting and the first 

harvesting time. This was about a 4-day difference. Accumulated yield quantity <strong>of</strong> 

grafted plants reached that <strong>of</strong> ungrafted plants at 1076 °C. This means that about 18 

days passed from the first harvesting <strong>of</strong> ungrafted plants to the date, when the 

accumulated yield quantity <strong>of</strong> grafted plants reached it in the average <strong>of</strong> <strong>grafting</strong> and 

planting combination. 

Figure 2 shows trend lines drawn in the course <strong>of</strong> the harvesting period. In both 

cases a linear trend line could be fitted. The difference between the two lines is the 

incline, as we harvested more yield from grafted plants in the same period. Equations <strong>of</strong> 

trend lines show that we harvested one kilogram <strong>of</strong> fruits at every 88 °C and 60 °C from 

ungrafted and grafted plants, respectively. 

Fig. 1. Accumulated yield quantity <strong>of</strong> tomato fruits from grafted and ungrafted plants. 

—: Ungrafted; : grafted


Fig. 2. Relationship between accumulated yield quantity and sum <strong>of</strong> effective temperature. 

: Ungrafted; : grafted; —: trend line (ungrafted); : trend line (grafted) 

Optimum temperature for tomato is 22±7 °C, however, if the temperature is below 

10 °C or above 32 °C it limits the growing. If the temperature is higher than the 

optimum during the ripening the early yield will be higher, but the total yield quantity 

will be lower. According to Fig. 2 we harvested the total yield at 744 °C and 913 °C 

from ungrafted and grafted plants, respectively. 

During the vegetation period the temperature exceeded 87 times the 32 °C and 

from this there were 27 days when it was above 40 °C. Temperature was below 10 °C 

20 times on ungrafted plants and 15 times on grafted plants (because <strong>of</strong> the different 

planting time). Grafted plants tolerated better the out <strong>of</strong> optimum range temperatures, 

therefore, they were able to produce more fruits. We examined separately the number 

and weight <strong>of</strong> fruits that can cause these differences among the yield quantities between 

the grafted and ungrafted plants. 

Acta Alimentaria 34, 2005


Table 2 shows the average values <strong>of</strong> examined parameters on each truss. Data 

show that grafted plants produced much higher yield in each examined truss. It is 

mainly important for the first three trusses, because the difference is 120% between the 

methods. We examined 1.5 kg and 3.3 kg fruits from ungrafted and grafted plants, 

respectively. There were decreases in the differences at the upper levels that were 

probably caused by climate control. 


Table 2. Average number and weight <strong>of</strong> fruit on examined trusses 

Ungrafted Grafted 

Truss number weight yield 

<strong>of</strong> fruit (pc) <strong>of</strong> fruit (g) truss –1 number weight yield 

(kg) <strong>of</strong> fruit (pc) <strong>of</strong> fruit (g) truss –1 (kg) 

1 6.1 69 0.42 8.9 113 1.00 

2 7.1 58 0.42 9.1 130 1.20 

3 7.9 85 0.66 8.4 132 1.11 

4 8.6 97 0.83 7.4 119 0.88 

5 7.4 86 0.64 6.9 107 0.74 

6 6.0 80 0.48 7.0 102 0.71 

7 4.6 74 0.34 6.3 97 0.61 

8 4.7 57 0.27 4.9 78 0.38 

Average 6.5 76 0.51 7.4 110 0.83 

Total 524 – 4.06 589 – 6.63 

As can be seen in Table 2, the number <strong>of</strong> the fruits on the grafted plants was higher 

than that on ungrafted ones with the exception <strong>of</strong> truss levels 4 and 5. The fruit numbers 

were relatively high on ungrafted plants at the lower levels. The highest value was 

obtained at level 4 (8.6 pc per truss), but on the upper levels there was a considerable 

decrease, at levels 7 and 8 these values dropped below 5. We counted 6.3 pc in average 

at level 7 <strong>of</strong> the grafted plants. The highest value was found on the grafted plants at 

level 2 (9.1 pc). There were no significant differences (P>0.05) in the number <strong>of</strong> the 

fruits between the two methods. 

Difference in average weight <strong>of</strong> fruits between grafted and ungrafted plants was 

remarkable, though at upper levels the weight <strong>of</strong> the fruits were smaller in both crops. 

This decrease in weight was lower on grafted plants than on ungrafted ones, as the 

average weight <strong>of</strong> fruits was 57 and 78 grams on ungrafted and grafted plants, 

respectively, on level 8. 

The averages <strong>of</strong> the eight levels were 76 and 110 g on the ungrafted and grafted 

plants, respectively. There is a significant (P


Fig. 3. Frequency distribution <strong>of</strong> grades according to fruit quality and size <strong>of</strong> grafted and ungrafted plants. 

: Ungrafted; : grafted 

Comparing the extra and first classes, there was no significant difference between 

grafted and ungrafted plants (P>0.05). About 90% <strong>of</strong> the fruits were extra and first class 

in both cases. While no difference was observed in the quality, there was a marked 

difference in size. Percentage <strong>of</strong> yield in grade 5 was about the same in grafted and 

ungrafted groups (44.5% and 43.7% in extra and 6.9% and 6.7% in first class, 

respectively). But there was a difference between the yield <strong>of</strong> fruits from grafted and 

ungrafted plants in grades 4 and 6. Percentage <strong>of</strong> the fruits in grade 6 was higher, while 

grade was lower on grafted plants compared to ungrafted ones. Of course these changes 

are in connection with the weight <strong>of</strong> fruits. 

Table 3 and Fig. 4 show the average values <strong>of</strong> the main quality components. All <strong>of</strong> 

the parameters showed lower values on the <strong>grafting</strong> plants than on ungrafted ones. 

Studying the Brix° as the characteristic <strong>of</strong> soluble solids, the lowest value (5.95 Brix o ) 

was observed at the third sampling date on the ungrafted plants. But this percent is still 

higher than that <strong>of</strong> grafted plants’ fruit. In that case the highest Brix o value is 5.73. In 

average the Brix° <strong>of</strong> the ungrafted plants was higher by 13% than that <strong>of</strong> grafted ones. 

Acta Alimentaria 34, 2005



Table 3. Average values <strong>of</strong> the main quality components 

Sampling date 

18.06 

Ungrafted 

25.06 09.07 average 18.06 

Grafted 

25.06 09.07 average 

Soluble solids (Brix°) 6.38 6.11 5.95 6.15 5.13 5.73 5.53 5.46 

Carbohydrate (% FW) 3.49 3.09 3.28 3.29 2.32 2.71 2.90 2.64 

Acid (% FW) 0.46 0.51 0.43 0.47 0.44 0.51 0.41 0.45 

Carbohydrate/acid 7.59 6.06 7.62 7.09 5.28 5.31 7.07 5.88 

Fig. 4. Average value <strong>of</strong> the main fruit components. : Ungrafted; : grafted 

We observed 25% difference in average carbohydrate content <strong>of</strong> fruits from 

grafted and ungrafted plants. The least difference was observed in acid content. It was 

only 4% on average for the samples collected at three different dates. 

The ratio <strong>of</strong> sugar and acid content is an important parameter, which determines 

flavour and sensory characteristics <strong>of</strong> tomato. The decrease <strong>of</strong> sugar content was not in 

relation to the loss <strong>of</strong> acid content on grafted plants compared with ungrafted ones. 

Because <strong>of</strong> the decrease <strong>of</strong> sugar content was much higher than that <strong>of</strong> acids, their rates 

were markedly different for the two methods. The average <strong>of</strong> this parameter is smaller 

by 20% on grafted plants than on ungrafted ones (5.88% and 7.09%, respectively). It is 

accepted that the best ratio <strong>of</strong> sugar to acid is from 9 to 10. The value <strong>of</strong> crop from 

ungrafted plants approached better this optimal value than that from grafted ones. 

Marked differences could be noticed in fruit components among the harvesting times.


Table 4 shows the probability values. There were no significant (P>0.05) differences in 

acid content between the grafted and ungrafted plants and in the Brix° <strong>of</strong> the ungrafted 

plants between the harvesting times. 

Table 4. Probability values (P) for the effects <strong>of</strong> the method and harvesting date 

Fruit components Method 

ungrafted 

Harvesting date 

grafted 

Brix° 0.05



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for improvement. Chapman and Hall Ltd, London, New York, pp. 281–334. 

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tomato fruits. J. Korean Soc. Hort. Sci., 38, 603–607. 

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