Vorobyova Y. The Formation of Seed Productivity of Winter Wheat under the Conditions of the Western Forest-Steppe of Ukraine

It is established that the variety and weather conditions during the period from the maturing beginning before full ripeness are limiting factors of cultivation of winter wheat for seeds in the zone of risky conducting seed growing of the western Forest-Steppe. The adaptive potential of varieties of different groups of ripeness and ecotype, their variation of phenotype under the influence of biotic and abiotic factors, peculiarities the destruction of plants and spica by diseases, level of implementation of their genetic potential, the yield loss depending on the enzyme-mycotic exhaustion of seeds and change of indicators of seed efficiency, technological and sowing quality under the influence of this occurrence are investigated. It is proved that under the influence of a large amount of precipitation in the period of full ripeness and for the 4-th, 8-th, 12-th days after its coming biological properties of seeds decrease and crop losses occur in the varieties of different ripening group. Separately for the fourth day after coming full ripeness of crop losses were 1,9 15,1 %, for the eighth day - 3,2 1,89 % and for twelfth they increased to 4,7 23,4 %. The biggest losses weight of 1000 seeds for the twelfth day were observed at early-ripening varieties - 18,6 23,4 %, slightly lower - at middle-early-ripening (11,3 13,6 %) and at middle-late-ripening (4,7 %). This occurrence causes lowering in the next indicators of seed production of varieties; crop of seeds - for 5,1 19,1 %, yield of conditioned seeds - for 2,4 12,0 %, coefficient of reproduction of seeds - for 0,7 3,0 units, laboratory germination - for 1,7 4,1 %. The economic and bioenergy valuation about using of resistant varieties by enzymo-mycotic exhaustion of seeds, are presented. Key words: variety, seeds, field germination, winter hardiness of plants, leaf area of surface, resistance to diseases, crop, coefficient of seed multiplication, exit of conditioned seeds, technological indicators of grain, sowing qualities of seeds.