seeds, fruits, aggregate fruits, and parts of aggregate fruits used for planting. Planting material sometimes includes the parts of plants used for vegetative reproduction, for example, bulbs and potato tubers. In the USSR, state standards have been set for planting quality (germinating power, purity, susceptibility to disease and pests, moisture content, and 1,000-seed weight) and varietal quality (purity and, for some crops, specificity). Only certified seeds meeting these requirements may be planted. State seed inspectorates determine the quality of planting material by means of laboratory analysis, soil control, and test plots.
Planting material is divided by planting quality into three classes. Established for each class are the number of seeds for the main crop, the yield of the main crop, the amount of foreign matter, the number of seeds of other plants (including weeds), germinating power, and moisture content. For winter and spring varieties of soft wheat, the purity norms are 99 percent for class 1, 98.5 percent for class 2, and 97 percent for class 3; the germination rate is 95 percent for class 1, 92 percent for class 2, and 90 percent for class 3. Class-1 and class-2 seeds are planted for crops; class-3 seeds may be planted in exceptional cases and only in the well-tilled areas.
Planting material is also classified according to varietal properties into three categories. For most grains (including pulse crops) category-1 seeds are marked by 99.5 percent purity, cate-gory-2 seeds by 98 percent, and category-3 seeds by 95 percent. Only category-1 seeds may be planted for seed production; cate-gory-2 and category-3 seeds are used in commercial sowing.
Before storing, planting material is cleaned, sorted, and, if necessary, dried. It undergoes various types of preparation before planting. Data on the planting and varietal qualities of planting material are recorded in special registers maintained by each farm.
M. K. FIRSOVA