EFFECTS OF PLANTING DATE AND OF VARIETY ON THE FRUITING AND YIELD OF GREENHOUSE TOMATOES.
The present rate of development is expected to be accelerated in the next future, as the five-years programme provides for the construction of greenhouses in each county and henceforth the consequent extension of forced vegetables for a better supply on the market.
In the above said climatic zone, the light conditions are different comparatively with the plain zones where the forcing houses are far more widespread. Thus, though the annual length of sun brightness during the winter monthhs is shorter, still this index is more favourable than in some other zones. These circumstances lead to the idea that by choosing a more favourable period for growing forced tomatoes, i.e. during the month of March-April (instad of the prolonged ususal cycle 20 December — 30 June), it could be obtained an increase of the early marketable production.
In fact, our researches in the zone of the South plain pointed out the potent influence that the sowing and planting periods had on the growing and fruiting of forced tomatoes, as their behaviour was affected both by the variation of natural light conditions (Nistor Marcela, 1972 (4) ; Manescu B. & Serbanescu Doina, 1974 (3), and by the interaction of light and temperature in controlled environement conditions (Ceausescu I., 1971 (2), Voican V. 1972, (5).
It was also ascertained a different response of cultivars to the variation of light conditions, as a result of the planting period itself (Nistor Marcela, 1972 (4), Voican V., 1972 (6).
In order to assign the most suitable period for growing forced tomatose in the climatic conditions specific to Transylvanian tableland and as to obtain