Productivity and quality indicators of a large seed fraction of confectionery sunflower varieties cultivated at different plant populations

In 2015-2017, we studied the effect of planting density of 20, 30, 40, 50 thousand plants/ha on the yield of a large seed fraction, productivity, yield structure and quality in confectionery sunflower of varieties SPK, Lakomka, Oreshek, Krupnyak, Dzhinn and Belochka. We established that the yield of a large seed fraction decreases from 55-59 to 23-26 % in case of using screens with oblong holes 4.5 × 20 mm in size (fraction 45+) from the main seed fraction of 38+ and increase of plant density from 20 to thousands plants/ha. The highest yield of the 45+ seed fraction was obtained by growing sunflower with a plant density of 20 thousand plants/ha: Belochka - 1.80 t/ha, Dzhinn - 1.62 t/ha, Krupnyak and SPK - 1.56-1.58 t/ha, Lakomka and Oreshek - 1.48-1.53 t/ha. With an increase of plant density from 20 to 50 thousand plants/ha, the yield decreases from 1.48-1.80 to 0.58-0.67 t/ha, the thousand-seed weight decreases from 139-146 to 116-124 g, seed huskness decreases from 31.2-32.3 to 28.8-29.2 %, seed kernel yield decreases from 1.02-1.23 to 0.41-0.53 t/ha, thousand-kernel weight decreases from 94-101 to 82-87, depending on the variety, and the volume weight of the 45+ seed fraction increases from 333-337 to 344-350 g/l.