the selection of the best varieties of agricultural crops and the determination of the regions in which the varieties should be cultivated.
In the USSR varietal zoning is based on proposals from varietal-testing plots. The State Commission for Varietal Testing of Agricultural Crops of the Ministry of Agriculture of the USSR supervises varietal zoning. The zoning of varieties and hybrids is based on their suitability for the local conditions of a particular region. New varieties that have undergone varietal testing and surpass old varieties for certain criteria (yield, quality, resistance to diseases and pests) are introduced into a region to supplement or replace varieties that were zoned earlier.
In 1976, 4,915 varieties and hybrids (of the 11,455 tested in 1974) were introduced into various regions of the USSR: these included 3,142 Soviet-bred varieties, 827 local varieties, and 946 foreign-bred varieties. One hundred and five varieties (of 50 crops) were zoned for the first time. These included 27 cereal varieties; 13 varieties of industrial crops; 22 vegetable and melon varieties; ten corn varieties; 19 varieties of feed crops; and 14 fruit, berry, and grape varieties. Varietal zoning was first practiced in the USSR in 1929.
REFERENCESKatalog sortov plodovykh, iagodnykh kul’tur i vinograda, vkliuchennykh v gosudarstvennoe sortoispytanie. Moscow, 1963.
Katalog raionirovannykh sortov sel’skokhoziaistvennykh kul’tur. Moscow, 1974.