Nendel 38 | Jørgen Eivind Olesen 37 | Taru Palosuo 44 | John R. Porter 42,45,46 | Eckart Priesack 39 | Dominique Ripoche 47 | Mikhail A. Semenov 48 | Claudio Stöckle 17 | Pierre Stratonovitch 48 | Thilo Streck 33 | Iwan Supit 49 | Fulu Tao 50,44 | Marijn Van der Velde 51 | Daniel Wallach 52 | Enli Wang 53 | Heidi Webber 30,38 AbstractWheat grain protein concentration is an important determinant of wheat quality for human nutrition that is often overlooked in efforts to improve crop production. We tested and applied a 32-multi-model ensemble to simulate global wheat yield and quality in a changing climate. Potential benefits of elevated atmospheric CO 2 concentration by 2050 on global wheat grain and protein yield are likely to be negated by impacts from rising temperature and changes in rainfall, but with considerable 156 |

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Following the boom in durum wheat breeding, ancient wheat disappeared from the human diet and old durum wheat varieties were replaced by what is believed to be their better versions: higher yielding modern varieties grown in high-input systems. Breeders have worked intensely ever since to improve the quality of durum wheat traits -mainly gluten subunit alleles -to obtain superior technological quality in the main durum wheat end products (first pasta and then bread) but conflicts about predicting their quality still exist. This is because quality is neither governed by one trait alone nor conditioned by a single controllable factor. This review discusses the evolution of wheat varieties from ancient to old, and then modern durum wheat in terms of agronomy, genetics, technological, and end-product qualities. Environmental effects will not be discussed. Moving from ancient to modern durum wheat varieties, grain yield increased, grain protein concentration decreased, and gluten strength and dough toughness improved, ameliorating the quality of pasta but decreasing the durum wheat versatility.

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High protein content and a 'strong' gluten are required in durum wheat (Triticum turgidum L. var. durum) to process semolina into a suitable final pasta product. The variation in grain protein content and quality realized through breeding and the concomitant variation in biomass production and partitioning have been analyzed by comparing in a 2-year field trial, four groups of cultivars released in different eras and areas of breeding. Three groups of cultivars represented the evolution of the Italian germplasm from the first landraces and genealogical selections (Group 1) to the cultivars constituted by crossing Mediterranean types with Syriacum types (Group 2), and the modern dwarf and semi-dwarf cultivars (Group 3). Group 4 was an ICARDA collection of breeding lines bred for adaptation to high altitudes. The measured traits included both biomass production and its partitioning to the grain, and total nitrogen uptake and its partitioning to the grain. Grain protein percentage, gluten content and gluten index were utilized as quality traits. Breeding resulted in an increased earliness, reduced height without significant decreases in total biomass, and improved partitioning. The concomitant total nitrogen uptake did not change, whereas the changed biomass partitioning caused a parallel change in nitrogen partitioning, with an increase in nitrogen harvest index from 0.41 to 0.59. The lower protein percentage in the grains of modern cultivars was therefore not due to a reduced nitrogen uptake, nor to a lower NHI or to less milligram of nitrogen per grain, but to the dilution effect caused by the heavier grains of modern cultivars. A notable increase in gluten index was observed in the modern cultivars, reflecting an improvement in the pasta-making quality of grain proteins.

The importance of awns in durum wheat (Triticum turgidum L. var. durum) has to be evaluated whenever an increase in grain yield is expected due to a greater photosynthetic capacity of the awned ear. Awned and awnless isolines of durum wheat were compared in a 3-year field trial in Sardinia (Italy). Ear and flag-leaf size, radiation interception, canopy temperature, yield, and yield components were measured.Awns increased the ear surface area from 36 to 59%, depending on their length, which ranged from 5.5 to 13.8 cm. This resulted in an average 4% more radiation intercepted by the awned ears. Canopy temperature was 0.9�C lower, on average, in the awned isolines, and was negatively correlated with kernel weight (r = –0.85**, n = 10), although consistent and marked effects of awns on canopy temperature were only observed in the long-awned lines. Awns positively affected grain yield, with an average increase of 10 and 16%, respectively, in the 2 years in which they affected kernel weight. The irrelevant effect of awns on yield in the year characterised by a severe drought was a consequence of their early desiccation.The effects of awns on grain yield and kernel weight strongly depend on the genetic background, on awn length and functionality, and on the environmental conditions during grain filling.

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