Sunflower yield formation in the Northern Forest-Steppe of Ukraine as affected by plant density

Abstract

Purpose. The research was carried out to establish the features of productivity formation of different by morphotype sunflower hybrids depending on plant density.Methods. Field and statistical. Multifactorial field experiment was based on the following scheme: factor A – ‘hybrid’: ‘Ukrainskyi F1’, ‘P63LL06’, ‘NK Brio’, ‘NK Ferti’; factor B – ‘plant density’: 50, 55, 60, 65 thousand pieces/ha.Results. Field multifactorial experiment was established and conducted in the Left-Bank Forest-Steppe of Ukraine during 2016–2018 on light loam chernozem. The highest yield was formed by hybrid ‘NK Brio’ with a range of changes depending on year conditions and plant density from 3.20 to 4.20, with an average yield 3.63 t/ha for all variants. The hybrid ‘NK Ferti’ formed a fairly stable yield - with a range of changes from 2.70 to 3.79 t/ha and an average yield 3.27 t/ha. The yield range of hybrid ‘P63LL06’ was 2.58-3.52 t/ha, average for all studied factors - 3.12. The yield of hybrid ‘Ukrainskyi F1’ varied from 2.16 to 3.11 t/ha, with an average 2.62 t/ha. The share of factors influence on sunflower yield formation is established. The biggest share in yields formation has the factor ‘hybrid’ - 58 %, also plays an important role ‘plants density’ – 14 %; interaction of factors “hybrid” and “plant density” - 18 % and factor - “conditions of the year” – 9 %. Conclusions. The lowest level of productivity was provided by cultivation of early-ripening hybrid ‘Ukrainskyi F1’, while cultivation of medium-ripe sunflower hybrid ‘NK Brio’ averaged 3.93 t/ha of seeds over the years of research with plant density 60 thousand pieces/ha. Productivity level of sunflower hybrids strongly depends on the density of sowings (correlation coefficients were obtained at the level of positive strong and very strong connection). Different precocious sunflower hybrids do not react equally to sowings density - it is necessary not only to select optimal areas for growing hybrids, but also to determine the optimal density of plants in the sowings. Due to agrocenosis formation with optimal plant density provides an increase in its productivity.