PRINCIPAL ASPECTS OF GREENHOUSE TOMATO BREEDING IN BULGARIA
As the greenhouse tomato production started since 1960 to be extended at an industrial scale principally for exportation, the variety Zaria-Comet, lost his significance in favor of Dutch varieties, among which Extase was helding longer an important place.
Now and much more in the future, the variety must detain a complex of properties such as high productivity, supperior fruit qualities, multiple resistance against the most important diseases and pests, possibilities to be cutlivated with low labor requirements, a.o.
This goals and, on the other side, the relatively specifical climate, soil and farming conditions, are representing the start points of the amplified developing of greenhouse tomato breeding in this country.
In Bulgaria are common three cycles of cropping: winter, spring and autumn crop.
The winter cycle, the basical one, is situated in the period September-June, the spring cycle in the period January-June, and the autumn cycle in August-January.
For the winter cycle, in which the plants are supporting the most unfavourable conditions, the breeding is oriented to create indeterminate varieties, with longer internodes, and fine, horizontal or half erected leaves. Such varieties would permit a better penetration of the light, and air through, which will favorise the photosynthese and fruit setting. In the same time the plants will be less affected by certain deseases (Botritys, Cladosporium, Phytophthora) and will permit an easier acomplishement of the works (thieving, pollination, irrigation, harvesting).