Sunflower yield and seed quality depending on elements of adaptive cultivation technology

Influence of the different seed sowing rates (the plant population 40, 60 и 80 thousand pants per ha) on productivity of new and perspective sunflower varieties (Skormas, Umnik, Master) and hybrids (Mercury, Typhoon, Imidzh, Oksi, Nataly) having the various duration of vegetative period, developed at the All-Russia Research Institute of Oil Crops by Pustovoit V.S. was studied in condition of unstable moistening on typical chernozem (Korenovsk district of the Krasnodar region) in 2016-2017. It is determined that at sufficient quantity of accessible moisture before crop planting, increase of seed sowing rate from 40 to 60 and 80 thousand seeds per ha promotes significant increase of yield (by 0.22 and 0.30 t per ha, respectively) in favorable on moistening year and yield decrease (by 0.14 t per ha at 80 thousand plants per ha compared to 60 thousand plants per ha) in unfavorable year in case of less water supply of plants during crop vegetative period and high daily average air temperatures during flowering and seed formation. On an average for these years the maximal yield was noted for the hybrids Nataly (3.42 t per ha) and Typhoon (3.30 t per ha), varieties Master (3.27 t per ha) and Umnik (3.26 t per ha); this certifies a high potential of these genotypes in the different weather conditions. The new very early maturing variety Skormas was differed with a low level of response on changes of seeds sowing rate independently the weather conditions of the year. The varieties Umnik (52.5%), Master (51.8%), Skormas (49.4%) and a hybrid Merkury (49.1%) had high oil content in seeds. And increase of seed sowing rate from 40 to 60 and 80 thousand per ha causes oil content rise in all studied varieties and hybrids, except the variety Master at a rate of 80 thousand seeds per ha. Overcrowding of sunflower sowings at increase of seed sowing rate from 40 to 60 and 80 thousand per ha in the different of moistening years did not influence generally on oil yield of varieties and hybrids, except the hybrid Typhoon which positively react on such increase.