Shapar L. Seed production of winter rape varieties depending on sowing time and seeding rates in the southern steppes of Ukraine

Object of study – the processes of growth, development, seed productivity formation, photosynthetic activity and water consumption of the winter rape variety in the conditions of the Southern Steppe. Aim – to specify the characteristics of the winter rape variety certified seeds depending on the biological potential of the genotypes under the study, sowing date and seeding rates in the southern steppe of Ukraine on irrigated lands. Methods – field, laboratory method aimed at determining the effect of the factors under study on the plant biometric characteristics, plants mass above surface and their leaf area, the productivity; calculation-comparative method aimed at assessing the economic and bioenergetics efficiency of the crop cultivation; statistical method aimed at justifying the reliability of the obtained research results. Results – based on the results of the studies conducted “Scientific and practical recommendations on winter rape cultivation technology in the southern steppe of Ukraine under irrigation” have been developed and published. The optimal sowing time and seeding rate have been determined which ensure high yield of certified seeds and high net reproduction coefficient of the appreciable varieties. It has been determined that for the irrigated zone of the Ukrainian southern steppe the Antaria winter rape variety ensures high certified seed productivity and yield if sown in the first ten-day period of September, the seeding rate being 1.1 million seeds per hectare. Novelty – for the first time in the southern steppe of Ukraine under irrigation there have been established growth and development characteristics of such winter rape varieties as Antaria, Senator Lux, Anna, Cheremosh, etc as well as their seed productivity depending on different sowing date and seeding rate; there has been accessed the effect of the factors under study on their photosynthetic potential; there has been determined the effect of productivity structural elements on certified seed yield. The dynamics of the net reproduction coefficient depending on the agronomy technology factors and variety genetic peculiarities has been established. Based on the correlation analysis, the effect of the cultivation technology elements on yield and seed sowing qualities has been established. The scientific value – certain elements of the rape varieties cultivation technology have been improved, which makes it possible to increase certified seed yield and the net reproduction coefficient of appreciable genotypes adapted to southern steppe conditions. Sector – agriculture.