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Development of winter wheat (Triticum aestivum) synthetics started at CIMMYT-Mexico in 2004, when winter durum wheat (Triticum turgidum) germplasm from Ukraine and Romania was crossed with Aegilops tauschii accessions from the Caspian Sea region. Chromosomes were doubled after pollination and embryo rescue, but chromosome number and cytological validation was not performed. F2 populations were grown in Mexico and were shipped to Turkey in 2008. During 2009–2015, these populations were subjected to rigorous pedigree selection under dry, cold, disease-affected environments of the Central Anatolian Plateau. The wide segregation and partial sterility observed in 2009 gradually decreased and, by 2016, most of the F8 single spike progenies demonstrated good fertility and agronomic performance. Since 2013, lines have been selected from synthetic populations and evaluated at multiple sites. Superior lines were characterized for resistance to leaf, stripe and stem rust, plant height, and reaction to common bunt and soil-borne pathogens. Thousand kernel weight of many lines exceeded 50 g, compared with the check varieties that barely reached 40 g. Threshability of synthetic lines varied from 0 to 95%, demonstrating genetic variation for this important domestication trait. Screening against Hessian fly, sunny pest and Russian wheat aphid identified several resistant genotypes. Both durum and Aegilops parents affected synthetic wheat traits. Several studies are underway to reveal the genetic diversity of synthetic lines and the basis of resistance to diseases and insects. This synthetic germplasm represents a new winter bread wheat parental pool. It is available upon request to interested breeding/research programmes.
Stripe rust, caused by Puccinia striiformis f.sp. tritici (Pst), is an important disease of winter wheat in Central Asia. Stripe rust races contain diverse virulence/avirulence patterns and change rapidly. Therefore the objectives of this research were to: (i) examine current pathotype variability of Pst races collected from Kazakhstan and Uzbekistan and (ii) evaluate stripe rust resistance in leading cultivars and advanced breeding lines targeted to those regions. Analyses of 152 Pst samples showed diverse virulence patterns with avirulence to Yr5, Yr10 and Yr15 being common. Most of identified races are among the rare. Analysis of a mixed Pst population showed 10 distinct pathotypes with frequencies ranged from 1.2 to 8.7%. The virulence patterns ranged from least ‘31–1.5’ and X-1.5 to highly virulent ‘86 + E16’. Seedling evaluation of 62 genotypes using the 10 pathotypes showed variations for resistance. Bunyodkor and Barhayot showed resistance to all pathotypes. Five Yr genes were postulated. Yr1 in KR12-5075, and Yr6 in KR11-03 and KR12-5003 were postulated. Yr5 combined with Yr10 and Yr15 genes were determined in Bunyodkor. The wheat genotypes also showed different levels of resistance in adult plant stage under field conditions. Twenty genotypes showed <20% severity in both Kazakhstan and Uzbekistan. The disease severity on several genotypes differed in this countries, suggesting different Pst populations in the two countries. Several resistant genotypes were identified, which should be further evaluated for release as new varieties or used in breeding programmes. Two resistant lines from this study were identified as new varieties in Georgia and Uzbekistan.
This paper summarizes a study initiated by the Turkish General Directorate of Agricultural Research and ICARDA/CIMMYT Wheat Improvement Program on the adoption of five new winter and spring wheat varieties developed and released by the Turkish national breeding program and through international collaboration in the past 10 years. The study results are based on a survey of 781 households selected randomly in the Adana, Ankara, Diyarbakir, Edirne, and Konya provinces of Turkey. The five new wheat varieties are compared to old improved varieties released prior to 1995 that are also still grown by farmers. Technical and biological indicators of impacts including crop productivity are measured to determine the impact of these varieties. Yield stability is assessed by comparing average yields in normal, good and dry years and by comparing the coefficients of variation of yields by variety. Profitability is measured by the gross margin generated per unit of land. Household income from wheat and for all economic activities are estimated and compared between adopters and non-adopters. Adopters of the new varieties have higher per-capita income than non-adopters as compared to the same group using old varieties. However, the overall impact of the improved varieties is generally low, mainly due to their low adoption levels. Farmers’ knowledge and perception of certain variety characteristics and unavailability of adequate and timely seed are the main reasons. Increasing adoption has the potential to improve household income and this requires revising wheat impact pathway to achieve the expected impact.
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