Productivity and Disease Resistance of Primary Hexaploid Synthetic Wheat Lines and their Crosses with Bread Wheat

Hexaploid synthetic wheat, derived from crosses between durum wheat and Aegilops tauschii, is widely accepted as an important source of useful traits for wheat breeding. During 2015 and 2016, three groups of synthetics were studied in Azerbaijan (3 sites) and Russia (1 site). Group 1 comprised CIMMYT primary synthetics derived from eastern European winter durum wheats crossed to Ae. tauschii accessions from the Caspian Sea basin. Group 2 included lines derived from CIMMYT synthetics x bread wheat crosses. Group 3 consisted of synthetics developed in Japan by crossing durum variety Langdon with a diverse collection of Ae. tauschii accessions. Varieties Bezostaya-1 and Seri were used as checks. Group 1 synthetics were better adapted and more productive than those in group 3, indicating that the durum parent plays an important role in the adaptation of synthetics. Compared to Bezostaya-1 synthetics produced fewer spikes per unit area, an important consideration for selecting bread wheat parents for maintenance of productivity. Synthetics had longer spikes but were not generally free-threshing. All synthetics and derivatives had 1000-kernel weights comparable to Bezostya-1 and significantly higher than Seri. All primary synthetics were resistant to leaf rust, several to stem rust, and few to stripe rust. Superior genotypes from all three groups that combine high expression of spike productivity traits and stress tolerance index were identified.