Optimization of seeding time for obtaining high productivity of top-quality seeds of durum wheat

In 2013-2016, under the conditions of the southern forest-steppe of Western Siberia, grain productivity and sowing qualities of durum spring wheat seeds were studied at the Experimental Field of the Seed Production Department of the Federal State Budgetary Scientific Institution “Omsk Agrarian Scientific Centre”, according to the sowing period (May 7th, 14th, 21st, 28th and June 4th) and the forecrop (pure fallow and grain crops). Object of the research were the intensive variety Zhemchuzhina Sibiri and extensive variety Omskiy korund. With sufficient and excessive moisture in June, the optimal sowing time for the formation of grain yield for the variety Zhemchuzhina Sibiri was May 7th-14th when sown after fallow, May 14th after grain crops; for the variety Omskiy korund was May 14th-21st when sown after both forecrops. In the years characterized by June drought, the optimal time for sowing both varieties when sown after both forecrops shifted towards May 28th (end of the month). In case of good moisture in the summer period, both varieties provided almost the same level of grain productivity when placed after both forecrops; in case of shortage of June precipitation, durum wheat sown after pure fallow provided an advantage of 0.24-0.36 t/ha at optimal sowing times in comparison with sowing after grain forecrops. Under the conditions of normal and excessive moisture in June, when sowing after pure fallow, the seeds of the variety Zhemchuzhina Sibiri were characterized by the maximum indices of germination energy and seed germination when sown on May 14th-28th, the seeds of Omskiy korund - on May 14th-21st; after grain forecrops, on May 7th-21st and May 7th-14th, respectively. In case of an acute shortage of June precipitation in both varieties, when sowing according to the studied forecrops, seeds with high sowing qualities were formed when sowing from May 7th to 28th. When sowing on June 4th, there was a significant decrease in grain productivity and sowing qualities of durum spring wheat seeds.