A population of 96 doubled haploid lines (DHLs) was prepared from F1 plants of the hexaploid wheat cross Chinese Spring x SQ1 (a high abscisic acid-expressing breeding line) and was mapped with 567 RFLP, AFLP, SSR, morphological and biochemical markers covering all 21 chromosomes, with a total map length of 3,522 cM. Although the map lengths for each genome were very similar, the D genome had only half the markers of the other two genomes. The map was used to identify quantitative trait loci (QTLs) for yield and yield components from a combination of 24 site x treatment x year combinations, including nutrient stress, drought stress and salt stress treatments. Although yield QTLs were widely distributed around the genome, 17 clusters of yield QTLs from five or more trials were identified: two on group 1 chromosomes, one each on group 2 and group 3, five on group 4, four on group 5, one on group 6 and three on group 7. The strongest yield QTL effects were on chromosomes 7AL and 7BL, due mainly to variation in grain numbers per ear. Three of the yield QTL clusters were largely site-specific, while four clusters were largely associated with one or other of the stress treatments. Three of the yield QTL clusters were coincident with the dwarfing gene Rht-B1 on 4BS and with the vernalisation genes Vrn-A1 on 5AL and Vrn-D1 on 5DL. Yields of each DHL were calculated for trial mean yields of 6 g plant(-1) and 2 g plant(-1) (equivalent to about 8 t ha(-1) and 2.5 t ha(-1), respectively), representing optimum and moderately stressed conditions. Analyses of these yield estimates using interval mapping confirmed the group-7 effects on yield and, at 2 g plant(-1), identified two additional major yield QTLs on chromosomes 1D and 5A. Many of the yield QTL clusters corresponded with QTLs already reported in wheat and, on the basis of comparative genetics, also in rice. The implications of these results for improving wheat yield stability are discussed.

Sixty-six spring and winter common wheat genotypes from Central Asian breeding programs were evaluated for grain concentrations of iron (Fe) and zinc (Zn). Iron showed large variation among genotypes, ranging from 25 mg kg -1 to 56 mg kg -1 (mean 38 mg kg -1 ). Similarly, Zn concentration varied among genotypes, ranging between 20 mg kg -1 and 39 mg kg -1 (mean 28 mg kg -1 ). Spring wheat cultivars possessed higher Fe-grain concentrations than winter wheats. By contrast, winter wheats showed higher Zn-grain concentrations than spring genotypes.

This regional synthesis addresses a major gap in knowledge about the effects of COVID-19 on agriculture and food across Asia • Key informants from 20 Asian countries assessed early direct and indirect effects on each of four major regional farming and food systems • The analysis showed Asian farming and food systems were moderately resilient to the pandemic, especially the hill mixed system • System resilience, food and labour markets, and farm and food chain economic benefits are key priorities for recovery policies and programmes • This study highlights COVID-19 effects and informs recovery policies and precautionary strategies against future pandemics in Asia and globally

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.

Historical changes in grain yield and quality of spring wheat varieties cultivated in Siberia from 1900 to 2010. Can. J. Plant Sci. 93: 425Á433. This study focusses on changes in yield, protein content, micronutrient composition and bread-making quality of 32 historical bread wheat varieties. The germplasm was divided into four groups: viz. 1: bred before 1935; 2: bred 1955Á1975; 3: bred 1976Á1985; 4: bred after 1985. Yield genetic gain was 0.59% per year. The last three periods scored significantly higher for protein, gluten content and alveograph W values, compared with the first group, but did not differ significantly from each other. The physical dough properties of varieties developed between 1976 and 1985 were superior, as reflected by the W value, farinograph mixing time and degree of softening. Loaf volume was highest for the 1950Á1975 group, representing a 15.6% superiority. There were significant and gradual reductions between the earliest and latest groups for protein (7.6%) and wet gluten (7.7%) contents. No changes in zinc and iron contents, important in determining grain nutritional value, were detected. Generally, modern germplasm had superior physical dough quality and stability. This improvement was not clearly associated with changes in the frequencies of high-and lowmolecular weight glutenin alleles. Sustaining the genetic gains for yield and quality will require investigation of the effects and interactions of genes controlling adaptation and end-use quality of spring wheat in Siberia.