Vlashchuk O. Seed productivity of annual white sweet clover varieties depending on agro-technological cultivation techniques under conditions of the South of Ukraine

Object of study – processes of growth, development, formation of seed productivity, photosynthetic activity, water consumption of white sweet clover under non-irrigated conditions of the South of Ukraine. Aim – to identify the specifics of the formation of seed productivity of different varieties of annual white sweet clover by optimizing the parameters of row spacing and nitrogen fertilizer doses under non-irrigated conditions of the South of Ukraine. Methods – field, laboratory, computational, statistical. Results – on the average, the highest index of seed productivity – 556.0 kg/ha, the maximum productivity of certified seeds – 495.0 kg/ha, and the maximum output of certified seeds of annual white sweet clover – 89.0 % were obtained when sowing the white sweet clоver variety Pivdennyi with the row spacing of 45 cm and the nitrogen fertilizer dose N60. The average coefficient of phenotypic variation (Vpf, %) of the output of certified seeds depending on row spacing was insignificant and ranged from 1.73 to 2.45 % for the variety Pivdennyi and from 1.85 to 2.15 % – for the variety Donetskyi Odnolitnii. Modification variability (Vm, %) was somewhat higher depending on application of nitrogen fertilizer doses being 2.65–9.26 % for the variety Pivdennyi and 2.71–9.38 % for the variety Donetskyi Odnolitnii, that indicates advantages of technological regulation of the output of certified seeds by means of this agro-technological measure. White sweet clover seeds of the variety Pivdennyi (Factor А) were characterized by higher germination energy – the average value of the index equaled 77.4 %, whereas that of the variety Donetskyi Odnolitnii was 77.1 %. Application of different parameters of row spacing (Factor В) also affected seed germination energy. The highest average value of the index – 79.1 % was obtained when using the row spacing of 45 cm, the lowest value – 75.6 % was obtained when using the row spacing of 15 cm. By Factor С (nitrogen fertilizer dose) the maximum seed germination energy – 78.0 % was identified when applying the nitrogen fertilizer dose N60. Тhe highest cost of the gross product per hectare – 55600 UAH/ha, the maximum net profit in the experiment – 43827 UAH/ha, the lowest cost price from per ton of the seeding material – 21174 UAH and the highest level of profitability – 372.0 % were obtained in the crop areas of the variety Pivdennyi with the row spacing of 45 cm and application of the nitrogen fertilizer dose N60. Novelty – for the first time the elements of agro-technology for different varieties of annual white sweet clover under non-irrigated conditions of the South of Ukraine were improved; a complex effect of row spacing and nitrogen fertilizer doses on the formation of the crop seed productivity was determined. The capability of different white sweet clover varieties to form stable yields of certified seeds in the years differing in weather conditions depending on the factors under study was determined and substantiated. The scientific value – scientific ideas concerning the specifics of plant growth and development of annual white sweet clover, formation of seed productivity and quality depending on variety assortment, row spacing and nitrogen fertilizer doses under non-irrigated conditions of the South of Ukraine were further developed. Sector – agriculture.