The impact of plant population on the productivity of confectionary sunflower varieties

In 2015-2017, the formation of productivity of six sunflower confectionary varieties (Oreshek, Lakomka, SPK, Dzhinn, Belochka and Krupnyak of VNIIMK breeding) depending on plant population of 20, 30, 40 and 50 thousand plants per ha was studied on leached chernozem of the Krasnodar region. In 2015-2017, weather conditions during the sunflower growing season (May-August) were characterized by a sufficient amount of moisture in the before-sowing spring period (March-April), a sufficient amount of precipitation in May-July, abundant rainfall in May 2017 and in June 2015-2016, the lack of precipitation in August 2016-2017, and high daily average air temperature. During flowering and seeds ripening the average temperature exceeded the climate norm by 1.6-2.6 °С in July and by 3.6-4.5 °С in August. In the weather conditions of May-August 2015-2017 a high yield of studied sunflower varieties was obtained and the dependence of yield, seed oil content and oil collection on plant population was revealed. It was established that the highest yield of confectionary sunflower varieties is achieved when growing them at population of 40-50 thousand plants per ha (3.46-3.65 t per ha). With an increase of crop population from 20 to 50 thousand plants per ha, the oil content in seeds increases from 43.6-44.9 to 46.7-48.1%, and the oil collection increases from 1.16-1.28 to 1.49-1.54 t per ha.