Duration of the growing season of spring wheat varieties of different ripeness groups depending on the sowing time in the conditions of the Krasnoyarsk forest-steppe

Wheat varieties were used as objects of research: Novosibirskaya 29, Uyarochka - mid-early, Krasnoyarskaya 12, Kuraginskaya 2 - mid-ripening, Svirel - mid-late. Sowing dates are May 17 and May 25. The duration of the growing season of spring wheat varieties was determined to a greater extent by the number of days of the germination-earing phase. At different sowing dates, the mid-early varieties Uyarochka and Novosibirskaya 29 formed the same duration of germination-heading periods (52-54 days); in the varieties Kuraginskaya 2 and Krasnoyarskaya 12, this period decreased by two days at the late sowing time, and significantly reduced in the variety Svirel (by 6 days). In general, the duration of the growing season with a late sowing period decreased by 2-6 days, while the growing season of mid-ripening and mid- late varieties is longer than medium-early ones by 8-14 days. Mid-early varieties Novosibirskaya 29 and Uyarochka formed a yield of 3.02-3.32 t/ha, regardless of the sowing date. Varieties of spring wheat of the middle and middle late types Kuraginskaya 2, Krasnoyarskaya 12, Svirel significantly increased yields at the optimal sowing time: by 0.31 t/ha, 0.32 t/ha and 0.53 t/ha, respectively. Mid-ripening and mid-late varieties exceeded early-ripening biotypes in terms of yield at both sowing dates, providing an increase of 1.3 to 1.5 t/ha. The recommended sowing time for wheat Svirel, Kuraginskaya, Krasnoyarskaya May 12 - 17, for mid-early varieties - Uyarochka, Novosibirskaya May 29 - 27.