Effect of autumn vegetation conditions on overwintering of winter rye and wheat with different sowing dates

The research was carried out in order to study the effect of autumn vegetation conditions on the growth, development and overwintering of winter wheat and rye depending on different sowing dates. The work was performed in 2016–2019 in the conditions of the forest-steppe of the Ob region. The research material included the varieties of tetraploid winter rye Vlada and Tetra short and winter wheat varieties Novosibirskaya 40 and Novosibirskaya 3. Sowing was carried out on three dates: 1st – 23 August, 2nd – 31 August and 3rd – 7 September under bare fallow. The choice of the optimal sowing time creates favorable conditions for the growth and development of winter crops and their preparation for further overwintering. According to the studies, it was noted that the intensity of autumn shoot formation and plant growth to a greater extent depends on the duration of the autumn growing season. A decrease in the plant growth rate and formation of tillering shoots from the first sowing date to the third date was associated with a decrease in the sum of effective temperatures. When sowing on a later date, the sum of effective temperatures varied in the range of 90–197° over the years. Under these conditions, overwintering rate of winter rye remained at the level of 94–100%, while in winter wheat it decreased to 40%. The best option, which ensured the stability of winter resistance, was the second sowing date (August 31) with a sum of effective temperatures of 250-300°, whereby the plants formed 3–4 tillering shoots and the plant height reached 18–25 cm. Winter rye outperforms winter wheat in autumn growth rate, shoot formation and in the vegetation cone development.