Growth, Development, Yield and Quality of Middle and Large Fruit Size Greenhouse Tomato - On-Farm Research

Four tomato cultivars from the Seminis Vegetable Seeds Company: large size Red Chief F₁ and Ivone F₁ fruits and middle size Flexxione F₁ and Brillant F₁ fruits were used in the experiment. There were six plants on each slab of rockwool. Plant density was 2.5 plants·m^-2. Tomato plants were grown according to a system for one main shoot or two shoots in which case fruits for the experiment were collected from the main shoot or from fruit bearing lateral shoots (two plants on each mat). The measurements included a week's increase of the shoot length, the diameter of the stem, the length of the leaf, number of leaves, number of blooming cluster, number of cluster set, number of harvesting cluster and plant loading with fruits.

Fruit firmness as well as the content of dry matter, vitamin C, total sugars, titratable acidity, pH of the cell sap, soluble solids, NO₃, P, K, Ca and the content of nutrients such as N, P, K, Ca in the leaf samples which allowed the assessment of the state of plant nutrition, were determinared. Large size fruit tomato cultivars produced higher total commercial yield than middle size fruit cultivars. Middle size fruit cultivars produced higher early yield. The large size fruit cultivars showed better yielding in the autumn than the middle size fruit cultivars. The plant growth depended on the type of the cultivar. The stem diameter of tomato plant depended on the cultivation conditions. A smaller stem diameter was observed with the higher EC in the root environment. In 2006 fruits were characterized by a higher content of vitamin C, total sugars, soluble solids, nitrates, phosphorus and calcium than in the year 2007. Higher values of chemical components (dry matter, vitamin C, titratable acidity, soluble solids, nitrates, phosphorus, potassium and calcium) were obtained in tomato fruits harvested in summer than in autumn time. Large size fruits contained a little more dry matter, total sugars, nitrate ions and phosphorus, but less vitamin C than middle size fruits. On the other hand, middle size tomato fruits were firmer than large size fruits and contained more vitamin C and calcium. No clear differences in fruit quality were observed depending on different systems of plant growing.