GROWTH AND REPRODUCTIVE MANIFESTATIONS OF TOMATOES GROWN IN UNHEATED POLYETHYLENE GREENHOUSES
These peculiarities in the greenhouse microclimate have a definite effect on tomato growth and reproductive manifestations.
The study conducted with the variety No 10 x Bison showed that at simultaneous planting in the greenhouse and outdoors (5–10 April) the greenhouse plants develop at an accelerated rate and fruits maturate 2–7 days earlier than those of early outdoors-grown tomatoes. Greenhouse-grown fruits maturate 10 to 13 days earlier when planted at the optimal date (25 March).
The growth dynamics is shown in fig. 1. Greater and faster vegetative biomass accumulation is observed in the greenhouse compared to that in the open.
On simultaneous planting, the dry weight of a plant in the phase red fruit at the third inflorescence in the open is 182.4 gm and in the greenhouse 242.2 gm. The difference is 68.9 gm at the optimal planting date 25 March. The dry weight difference between the second and third variants during the growing season varies, rising progressively from 9.3 gm on 3 May to 69.3 gm on 22 June. The average daily mass increase from planting to the phase red fruit at the third inflorescence is 2.23 gm in the open and 3.26 gm in the greenhouse. The daily increase in the greenhouse is bigger throughout the growing season, the maximal one amounting to 5.53 gm, and in the open 4.94 gm. The increase in the root system and overground organs - leaves, stems and fruits - shows the same regularity, i.e. the dry weight is heavier and the average daily increase is higher in the greenhouse than in the open. Data presented in fig. 1 reveal slowest growth and least daily increase in the roots, followed by stems and leaves and fastest increase in fruit weight. After the transplanting of the plants till the 25th day, the leaves and roots increase most fast and the fruits most slowly. During this period roots in the