Variability of biochemical parameters of seeds of the sunflower variety SPK plus depending on sowing dates

The article presents the results of the study of changes in biochemical characteristics of seeds of sunflower variety SPK plus at different sow-ing dates and depending on meteorological conditions of the year. The biochemical composition of economi-cally valuable traits of seeds of the variety SPK plus was determined. The patterns of oil and protein accu-mulation of this variety in relation to the duration of the growing season and the amount of precipitation in different periods were studied. The peculiarities of var-iability and ratio of biochemical components in seeds under different regimes of water availability during the growing season have been examined. The intensity of dynamic oil accumulation with increasing average daily temperatures and humidity during the observa-tion period was shown, which is in accordance with lit-erature sources and data of other researchers. The high content of glutamic acid (0.9–1.4%/kg AirDM) and as-partic acid (0.4–0.7%/kg AirDM) was observed at all sowing dates with a stable low content of other amino acids. Among essential amino acids, a high level of leucine was found at the first, second and fourth sow-ing dates (0.54, 0.56 and 0.55%, respectively) with weak dynamics of accumulation of other amino acids. The importance of breeding new population varieties of confectionery sunflower was emphasized. The pos-sibility of further breeding to improve the quality of sunflower seeds (oil/protein ratio) was evaluated. The average values of the mass fraction of protein in the range from 16.21 to 20.74% ADM, the content of the mass fraction of oil in the range from 38.2 to 43.7% ADM were determined. These factors are char-acterized by a weak negative correlation r = -0.44. At the same time, the intensity of the accumulation of the oil mass fraction with the increase of the average daily temperature and humidity indicators of the observation period is noted.