RESPONSE OF WINTER WHEAT VARIETIES OF LUTESCENS AND ERYTHROSPERMUM TO SOWING TIMES IN THE CONDITIONS OF THE NORTHERN STEPPE OF UKRAINE

Abstract

To obtain high and stable grain yields, favorable weather conditions are necessary throughout the entire vegetation period of plants, but the latter depend on natural factors that cannot be adjusted. By changing the sowing dates within acceptable limits, it is possible to influence the provision of plants with heat and solar radiation, that is, indirectly optimize the biotic and abiotic factors of the vital activity of grain crops. Winter wheat plants of different varieties have genetic differences in their needs for sowing dates, therefore, establishing the most favorable dates is of scientific and practical importance. The purpose of the research was to establish the most favorable sowing dates for winter wheat varieties Erythrospermum and Lutescens in the conditions of the Northern Steppe of Ukraine. The varieties of winter wheat Vezha (Lutescens) and Yuzovska (Erythrospermum) were used for the research. It was found that at later sowing dates (October 15 and October 25), the interphase period sowing-seedlings is extended compared to early dates by an average of one day, regardless of the variety. It was found that at the first sowing date (September 15), the longest autumn vegetation period was in the Yuzovska variety. When compared with the average multi-year norm, this indicator was 3 days longer. At later sowing dates, the duration of the autumn vegetation period gradually decreased regardless of the variety. Biometric indicators of winter wheat plants at the end of the tillering phase depended on both the sowing date and the variety under study. The highest tillering coefficient in the Vezha (Lutescens) variety was formed when sowing on September 15 – 2.82. Plants of the Yuzovska variety (Erythrospermum) at this sowing date formed a tillering coefficient of 2.77. The highest coefficients of productive tillering at the end of the growing season (2.15 and 1.83) of the Yuzovska variety (Erythrospermum) were formed by plants sown on September 15 and October 5, respectively. The best biometric indicators of plants of the Vezha variety (Lutescens) at the end of the growing season were formed during the first two sowing dates – September 15 and September 25, providing coefficients of productive tillering at the level of 2.03 and 1.88, respectively. Thus, it was established that the varieties of both varieties had the best biometric indicators for the sowing date of September 15.