In this country the systematic breeding work with vegetable crops using plant growing structures has begun in the late forties.
In 1968, 72 varieties and hybrids from 6 different crops (cucumbers, tomatoes, cauliflower, lettuce, radishes and shallot) were zonated in the USSR.
Along with the special varieties for plant growing structures, a substantial number of varieties taken from the field production have also been zonated.
Most of the zonated varieties have been developed according to the breeding method.
In practice, individual breeding is very often combined with the family or the group one.
Lately, however, breeding enterprises have adopted the hybridization method on a very large scale.
An important method designed to increase productivity has proved to be the inter-varietal crossing.
It has been applied for the development of a great number of tomato and cucumber varieties designed for greenhouse growing.
Aimed at improving the breeding methods for developing new varieties, suitable for plant growing structures, the achievements in the theory and practice of breeding work with vegetable crops grown in the open ought to be considered.
In this respect the achievements of modern genetics in developing polyploids and mutations under the influence of chemical and physical mutagens are of great interest.
In order that a successful breeding work be achieved, diverse initial materials, which would ensure the basic directions for developing varieties designed for plant growing structures, should be available.
The selection of such materials is designed not only for developing varieties and groups for growing in specific plant growing structures, but the zonal peculiarities ought also to be taken into consideration.
Thus, for example, most suitable for the northern regions of the country have proved varieties reacting positively to long days and decreased sun irradiation, and for the southern regions of the country varieties reacting positively to short days and intense sun irradiation.
The collection of vegetable crops of the N.I. Vavilor All-Union Scientific Research Institute is a copious source of the mentioned initial materials.
It comprises all crops needed for plant growing structures, namely cucumbers, tomatoes, peppers, salad crops, green onions and others.
They are represented by local and selected varieties of native and foreign provenances.
The collection comprises several semi-cultivated and wild forms as well.
It is obvious that the maintenance of the seed germinating capacity of a great number of collected samples requires much time and is a labour consuming task, being in close connection with periodical sowing.
Thus, the research work done by the Institute is in connection with keeping seed samples for a long period under storage conditions and is of great interest