Abstract
The study is devoted to a comparative analysis of adaptation and productivity of spring bread ( Triticum aestivum L.) and durum ( Triticum durum Desf.) wheat under agroecological conditions of Western and Northern Kazakhstan and Russia (Western Siberia) to enhance production and breeding. The methodology is based on the analysis of the results of long-term (2005–2024) field experiments of the Kazakhstan–Siberian Network for Spring Wheat Improvement (KASIB) at four scientific institutions: Karabalyk Agricultural Experimental Station (AES), Aktobe AES (Kazakhstan), Altai Scientific Center of Agrobiotechnologies, and Omsk Agricultural Scientific Center (Russia). The weather changes observed at the four breeding sites over 20 years were slightly different, owing to underlying regional variation. Seasonal precipitation tends to increase at Aktobe, the driest site, while temperature gradually increases at Barnaul and Omsk. Most of the temporal changes do not meet the significance test except air temperature increase at Barnaul. The results showed that under Kazakhstan conditions, spring bread wheat demonstrated insignificantly higher yield than durum (by 7%–21%), even though durum wheat forms taller plants and has a larger 1,000 grain weight. In Western Siberia (Altai Territory), durum wheat insignificantly outperformed bread wheat in yield by 8.6%. A strong positive correlation was established between yield and plant height, and 1,000 grain weight in both wheat species. Both crops showed similar sensitivity to elevated air temperatures in June and in May–July. The positive association between grain yield and rainfall was more pronounced for spring durum, suggesting its better response to moisture availability. Durum wheat expressed higher resistance to leaf rust. The two species’ distinct climate-response strategies operate through precipitation-driven disease pressure and differential responsiveness of yield and kernel weight to overall environmental favorability. The practical significance of the work consists in the possibility of a more informed choice of wheat species for specific agroecological conditions and the development of breeding strategies specific to each crop and across the species.