Yield of different sunflower hybrids depending on seeding rate

Abstract

The steady trend towards climate warming and aridization has led to the expansion and partial shift of the industrial sunflower growing area from the Steppe to the Forest- Steppe and Polissya zones. The range of soil, climatic and agronomic conditions in this region, which is different from the main growing zone, requires revision and optimization of the parameters of existing technologies, including the sowing density of modern hybrids. Plant density is increasingly seen as one of the most effective levers for managing crop yields. Incorrect calculation of seeding rates can lead to both thickening of crops and irrational use of seeds, as well as to their excessive liquefaction. To unlock the potential of a crop's biological yield, when determining plant density, soil and climatic conditions, variety or hybrid, and cultivation technology should be taken into account. The aim of the research was to study the peculiarities of yield formation of different sunflower hybrids and seed quality with an increase in sowing density compared to the existing recommendations. Research methods. For two years, a production experiment was conducted to study the effectiveness of growing two mid-season sunflower hybrids NK Condi (linoleic) and Suvango NST (high oleic) at different sowing densities in the conditions of Central Polissya of Ukraine. The arrangement of variants is systematic in three replications. The size of the plot is 0,145 hectares. Results. It has been proved that the hybrid of linoleum type of use NK Condi provided the highest yield (3,22 t/ha) at a seeding rate of 50 thousand/ha and a sowing density of 45 thousand/ha. When sowing was thickened to 62 thousand/ha (sowing 72 thousand/ha), the yield decreased by 0,11 t/ha, or 3,4%, but the highest oil yield per unit area was obtained. The optimal sowing density of the high oleic hybrid Suwango HTS under moderate moisture conditions is 45–50 thousand plants/ha (sowing rate 50–57 thousand/ha), and under sufficient moisture conditions – 55–60 thousand plants/ha (sowing rate 65 thousand/ ha). Such a sowing density provides not only high yields (2,71 and 2,66 t/ha, respectively), but also the highest yield of high-quality oil per 1 ha. Conclusions. In order to obtain high and sustainable yields of sunflower in the conditions of Central Polissya, it is advisable to grow the hybrid NK Condi with a sowing density of 45 thousand plants/ha at a seeding rate of 50 thousand seeds/ha. High oleic hybrid Suwango HTS under conditions of sufficient moisture should be grown at a density of 55–60 thousand plants/ha (seeding rate 65 thousand seeds/ha). This sowing density provides not only high yields, but also the highest yield of high-quality oil per 1 ha.