Yield, Physical and Chemical Characteristics of Greenhouse Tomato Grown on Soil and Organic Substratum

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1 Yield, Physical ORIGINAL and Chemical SCIENTIFIC Characteristics PAPER of Greenhouse Tomato Grown on Soil and Organic Substratum Yield, Physical and Chemical Characteristics of Greenhouse Tomato Grown on Soil and Organic Substratum Sima RODICA, Silviu Alexandru APAHIDEAN, Maria APAHIDEAN, Dănuţ MĂNIUŢIU, Laura PAULETTE University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, 3-5 Mănăştur Str., Cluj-Napoca, Romania, ( Abstract Type of culture substrate and variety are important factors to be considered for growing tomatoes. Five tomato hybrid varieties were cultivated in soil and organic substrate in the greenhouse to evaluate the yield and fruit quality. Maximum yields were obtained in case of organic substrate culture. Concerning fruit quality features some differences reveal among the tomato fruits obtained from the two culture systems. Thus, despite dry matter content of fruit was higher in case of soil culture, all varieties recorded higher total sugar content, titratable acidity and vitamin C content on organic substrate culture. None of the nitrate and nitrite values over passed the accepted limits of permission for greenhouse tomatoes. Key words: tomato, greenhouse, organic substrate, fruit quality Prinos i svojstva plodova rajčice uzgajane na tlu i u organskom supstratu Sažetak Vrsta supstrata i sorta važni su čimbenici za razmatranje u uzgoju rajčice. Pet hibridnih sorata rajčice uzgajano je na tlu i organskom supstratu u zaštićenu prostoru zbog vrednovanja prinosa i kvalitete plodova. Maksimalni su prinosi ostvareni u uzgoju na organskom supstratu. Što se tiče kvalitete plodova otkrivene su razlike između sorata iz dva sustava proizvodnje. Unatoč veće količine suhe tvari u plodovima biljaka uzgajanih na tlu, sve su sorte imale veću količinu ukupnih šećera, veću kiselost i količinu C-vitamina kada su uzgajane na organskom supstratu. Količine nitrata i nitrita u plodovima nisu prelazile vrijednosti propisanih ograničenja za rajčicu iz zaštićena prostora. Ključne riječi: rajčica, zaštićeni prostor, organski supstrat, kvaliteta ploda Introduction Greenhouse vegetable production offers advantages compared to production at the open field with regard to quality assurance principally, because the plants are not exposed directly to the rapid changes of climate conditions. Greenhouse soilless culture may be an alternative growing system for high-value vegetable crops including tomato. An important role for this purpose is also the cultivar selection by using tomato hybrid varieties with a high yield potential and a good fruit quality. Therefore, the research was conducted in 2005 and 2006 years, to evaluate yield, and tomato fruit physical and chemical characteristics. Proceedings. 43 rd Croatian and 3 rd International Symposium on Agriculture. Opatija. Croatia ( ) XXX) Vegetable Growing 439

2 Sima RODICA, Silviu Alexandru APAHIDEAN, Maria APAHIDEAN, Dănuţ MĂNIUŢIU, Laura PAULETTE Materials and methods Five tomato hybrid cultivars ('Matador', 'Marfa', 'Shirley', 'Graţiella', 'Amanda') were grown in greenhouse soil, and in 6 L volume polyethylene bags filled with mixed organic substrate. Organic substratum was prepared from brown peat (80%) and long duration follow soil + well decomposed manure (20%). The plant density was 41,600 per hectare at both culture systems. The transplants were planted in soil on the end of January and the bags with tomato plants were put at the final growing place on the second decade of February, in both years. The usual tomato cultivation methods were applied in conventional culture system. The cultivation methods established by Carpenter (1982) and adapted to local conditions by Indrea et al. (1990) were used for bag tomato growing. The measurements concerning quantity and quality of tomato fruits were done (shape, weight, firmness, dry matter content, total sugar content, titratable acidity, flavour intensity, ascorbic acid concentration). Results and discussions The harvest started in the second decade of April and it finished in the second decade of July in both years, due to a later period of culture setting up. Early yield had considered being that one recorded till 31 of May in both years. The analysis of reciprocal influence of all variants (Duncan test) shows significant early yield efficiencies for all cultivars in organic substrate culture (5 kg fruits per m 2, 60-80% yield efficiency rate) in comparison with soil culture (Table 1). The highest early yield was recorded by cv. 'Marfa' grown in soil (3.24 kg/m 2 ), and by cvs. 'Amanda' (5.49 kg/m 2 ), 'Matador' (5.36 kg/m 2 ) and 'Marfa' (5.19 kg/m 2 ) grown in bags with organic substrate. The analysis of reciprocal influence of both experimental factors on total yield of tomato (Duncan test) shows an apart behaviour of cv. 'Amanda', with a medium total yield of kg/m 2 on organic substrate, which assures a positive difference of 3.88 kg/m 2 in comparison with soil culture, followed by cv. 'Marfa' (9.92 kg/m 2 ) but which realized a good yield on soil culture too, the difference obtained by system culture changing (1.82 kg/m 2 ) being under errors limit (Table 2). On an average for both experimental years, organic substratum culture system obtained total yield efficiencies which varied between 46.0% at cv. 'Shirley' and 60.1% at cv. 'Amanda' in comparison with cv. 'Matador' cultivated in soil, took as control. Tomato fruit quality for fresh consumption is determined by appearance (colour, size and shape), firmness, texture, dry matter and organoleptic properties. The main physical characteristics of tomato cultivars, followed in the experiment, are presented in Table 3. The average height of fruits of the studied cultivars varied between 44.0 mm ('Matador') and 52.8 mm ('Amanda'). The same cultivars recorded the smallest (54.4 mm) respectively the biggest (66.0 mm) fruit diameter. The index of fruit shape was calculated as a proportion between the height and the diameter of fruit. It had very close values ( ) for all cultivars, thus they being defined as flat-round type. The firmness of the fruits, appreciated on a scale from 1 to 10, was very good, all cultivars obtaining scores between 8.8 and 9.6. The extreme firmness of fresh market tomato cultivars may be useful because they can be picked at later stages of ripeness, having better flavour characteristics. The values of correlation coefficient of the main physical characteristics which determine commercial aspect of tomato fruit (height, diameter, index of fruit shape) are presented in Table 4. Results indicated a significant positive correlation between fruit height and fruit diameter, as well as a strong positive correlation between fruit diameter and fruit firmness. It can be also remarked the negative correlation between index of fruit shape and fruit firmness, even if it is not significant (r = 0.570), which shows that flat-round fruit are more firm flesh. The flat-round shape, typical for open field tomato, could be as well a high commercial characteristic for greenhouse tomato. Fresh tomato quality is a complex characteristic, involving besides physical appearance and firmness, as well as flavor and nutritive value. Concentrations of dry matter, soluble solids, titratable acidity, volatile compounds, minerals, carotene and vitamin C in fresh fruit increase with increasing salinity (Dorais at al., 2000; Sonneveld at al., 1988; Stevens, 1979). In our experiment dry matter content of fruit varied between % for soil culture and % for organic substrate culture. The highest content of dry matter was recorded for cvs. 'Marfa', 'Matador' and 'Amanda' in soil culture (all with 6.5%) and for cv. 'Gratiella' (6.3%) in organic substrate culture (Table 5). For all cultivars, in case of organic substrate culture dry matter content rd Croatian and 3 rd International Symposium on Agriculture

3 Yield, Physical and Chemical Characteristics of Greenhouse Tomato Grown on Soil and Organic Substratum was lower maybe because of the higher obtained yields and due to the reverse correlation between the yield and dry matter content of fruits. Certain of the tomato cultivars differed greatly in flavour. Sweetness was determined largely by the content of total sugar, while sourness was related to titratable acidity. The highest sugar content of fruit was recorded by cv. 'Gratiella' in organic substrate culture (2.83%), while cv. 'Amanda' obtained the highest sugar content in soil culture (2.91%). The correlation between total sugar content and acidity was positive for both systems of culture even if just in case of soil culture it was significant (Table 6). With the highest levels of sugar and acidity, thus with greater sweetness, sourness, tomato-like character and flavor intensity were remarked cv. 'Amanda' in soil culture and cv. 'Graţiella' in organic substrate culture, among the studied cultivars. Vitamin C is a health-promoting factor with antioxidant properties. Even if the antioxidant content of tomato may depend on genetic factors, in case of a given variety it can varies according to the culture system. High vitamin C contents were recorded in case of organic substrate culture ( mg per 100 g of fresh matter). An important factor influencing the vegetable quality is the quantity of absorbed nitrogen and the way in which it is utilized in plant metabolism, mainly with respect to the nitrites and nitrates content of edible plant tissues. However, both these factors are better managed in hydroponics, since in the small volume of rooting medium the nutrient supply is more efficiently controlled through the composition of the nutrient solution. In our experiment the recorded values of nitrites and nitrates content of fruit were situated under normal accepted limits, even if they were a little bigger in case of organic substrate culture than in soil culture (Table 5). The lowest fruit nitrites content of tomato cultivars was recorded by cv. 'Gratiella' in soil culture (14.82 mg/kg) and by cv. 'Shirley' on organic substrate (16.17 mg/kg) and the lowest fruit nitrates content was recorded by cv. 'Gratiella' in soil culture (18.23 mg/kg) and by cv. 'Matador' on organic substrate culture (18.23 mg/kg). Table 1. The influence of cultivar and cultivation method on tomato early yield (kg/m 2 ), soil % substrate % + D average Matador (control) 2.94 bcd ab PQ Marfa 3.24 abcd ab P Shirley 2.92 bcd ab PQ Graţiella 2.12 d abc Q Amanda 2.35 cd a PQ Substrate average 2.72 M 5.15 N % DScultivar x substrate = ; DScultivar = ; DSsubstrate = 0.99 Table 2. The influence of cultivar and cultivation method on tomato total yield (kg/m 2 ), soil % substrate % +D average Matador (control) 6.44 b ab P Marfa 8.10 ab a P Shirley 7.13 ab ab P Gratiella 6.24 b a P Amanda 6.43 b a P Substrate average 6.87 M 9.80 N % DScultivar x substrate = ; DScultivar = ; DSsubstrate = 1.30 Table 3. Fruit physical properties of tomato hybrid cultivars grown in greenhouse, Fruit height (mm) Fruit diameter (mm) Fruit shape index Fruit firmness Matador Marfa Shirley Graţiella Amanda Vegetable Growing 441

4 Sima RODICA, Silviu Alexandru APAHIDEAN, Maria APAHIDEAN, Dănuţ MĂNIUŢIU, Laura PAULETTE Table 4. Values of correlation coefficient (r) of the main physical characteristics of five greenhouse tomato cultivars, Correlated properties Fruit diameter Index of fruit shape Fruit firmness Fruit height ** * Fruit diameter *** Index of fruit shape r5% = 0.811; r1% = 0.917; r0.1% = Table 5. Fruit quality characteristics of tomato hybrid cultivars grown in soil and organic substrate in greenhouse, Cultivation method Dry matter, % Total sugar, % Titratable acidity, % Vitamin C, mg/100 g Nitrite (NO2 - ), mg/kg Nitrate (NO3 - ), mg/kg Matador soil Marfa soil Shirley soil Gratiella soil Amanda soil Matador substrate Marfa substrate Shirley substrate Gratiella substrate Amanda substrate Table 6. Values of correlation coefficient (r) of the main chemical characteristics of five greenhouse tomato cultivarss, Correlated characteristics Fruit content Sugar Titratable acidity Vitamin C Soil Dry matter *** * Sugar * Titratable acidity Organic substrate Dry matter *** Sugar Titratable acidity r5% = 0.811; r1% = 0.917; r0.1% = Conclusions The best result of experience with greenhouse tomato cultivated in soil and organic substrate, which confirm our previous results, is that on organic substrate they can be obtained earlier yields than in soil. Cv. 'Marfa' recorded the highest yield both in soil and on organic substrate. At organic substrate it was obtained the highest yield that varied between 46.0% for cv. 'Shirley' and 60.1% for cv. 'Amanda' in comparison with control (cv. 'Matador', soil) in both years. The index of fruits shape had very close values ( ) for all cultivars. A strong positive correlation was recorded between fruits diameter and fruits firmness which reveals that flat-round shape fruits had better firmness. The total sugar content and acidity are the most important characteristics of tomatoes taste. With the highest levels of sugar and acidity, thus with greater sweetness, sourness, tomato-like character and flavour intensity were remarked cv. 'Amanda' in soil culture and cv. 'Graţiella' in organic substrate culture, among the studied cultivars. Nitrates content of tomato fruits was a little bigger in case of organic substrate culture for all the cultivars but none of them over passed the accepted values rd Croatian and 3 rd International Symposium on Agriculture

5 Yield, Physical and Chemical Characteristics of Greenhouse Tomato Grown on Soil and Organic Substratum References Carpenter, T. D. (1982). Analysing and managing nutrition of vegetables grown in upright polyethylene bags. Journal of Plant Nutrition 5(8): Dorais, M.; Dorval, R.; Demers, D.A.; Micevic, D.; Turcotte, G.; Hao, X.; Papadopoulos, A.P.; Ehret, D.L.; Gosselin, A. (2000). Improving tomato fruit quality by increasing salinity: effects on ion uptake, growth and yield. Acta Horticulturae 511: Indrea, D.; Apahidean, Al.S.; Apahidean, M.; Paven, I. (1990). Cercetări privind o nouă metodă de cultură fără sol, a tomatelor în sere. Buletin IACN, vol. 44 (2) Sonneveld, C.; Welles, G.W.H. (1988). Yield and quality of rockwool-grown tomatoes as affected by variations in EC value and climatic conditions. Plant and Soil 111:37 42 Stevens, M.A. (1979). Tomato quality: potential for developing cultivars with improved flavour. Acta Horticulturae 93: sa2008_0404 Vegetable Growing 443