INFLUENCE OF SEEDING TIME AND DENSITY OF PLANTS ON GROWTH AND PRODUCTIVITY OF THE SUNFLOWER

Abstract

With the advent o f new sunflower hybrids in manufacturing determining o f optimal parameters o f major growing agrotechnical practices for them, including plant density at different seeding time has a significant urgency. Analysis o f literary sources shows that for this purpose new hybrids listed in the State Register o f Plant Varieties o f Ukraine in conditions o f Right-Bank Forest-Steppe have not been investigated although they differ in the duration o f the growing season, morphotype, response to agrotechnical measures and resistance to diseases and drought. Therefore the purpose o f our research was studying these issues.The study was carried out during 2012-2014 in the field crop rotation o f Department o f Crop Production. Two-factor field experiment provided the following: term o f sowing depending on the soil temperature at a depth o f seeding - respectively 6 -8 °C (control), 10-12 and 14-16°C and plant density - 40 (control), 60 and 80 thousand o f plants/ha.As a result o f studies it is found that increasing plant density from 40 to 60 thousand o f plants/ha as well as postponement o f sowing from the second decade o f April to the second decade o f May contributes a considerable enhancing o f growth processes. To have the highest yield level the early sowing period was the most optimal when at the depth o f seeding the soil temperature was 6 -8 °C which provides obtaining seed yield over 2.0 t/ha.