From seed to bread: variation in quality in a set of old durum wheat cultivars.

BACKGROUND: Old durum wheat varieties are being appreciated again because of their interesting genetic diversity and low fertilizer needs. RESULTS: The agronomic and bread-making performances of 14 old Italian durum wheat varieties grown under two low nitrogen (N) inputs (46 and 86 kg ha-1 ) were determined and the relationships among grain, semolina, dough and bread quality parameters were established. The old varieties yielded similarly to the check modern variety Svevo under both N levels. Increasing N fertilization from 46 to 86 kg ha-1 did not increase grain yield or the mg of N in the grain, although grain protein percentage increased as a result of a decrease in grain weight and an increase in gliadin content. Despite the resulting decrease in the gluten index, dough and bread quality improved at the higher N rate, highlighting the influential role of protein percentage and gliadin in bread quality. The genotypic variation in grain protein percentage among old varieties was more strongly associated with glutenin than with gliadin content. Variation in the gluten index was high (4-54); indeed, it was the most variable semolina parameter, and proved to contribute the most to variation in bread quality. This variation was independent of the glutenin alleles (HMW 20, 20*, 7, 13+16, 6+8) and was linked to the quality of the grain in terms of grain weight and the associated mg of N per grain. Remarkably, two old varieties, namely Calabria and Cappelli, were able to produce both a good yield and high-quality bread. CONCLUSION: Old Italian durum wheats continue to boast significant biodiversity and are worth exploring in low-input production systems. © 2019 Society of Chemical Industry.

Climate change impact and adaptation for wheat protein.

Wheat 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 CO2 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 disparities between regions. Grain and protein yields are expected to be lower and more variable in most low-rainfall regions, with nitrogen availability limiting growth stimulus from elevated CO2 . Introducing genotypes adapted to warmer temperatures (and also considering changes in CO2 and rainfall) could boost global wheat yield by 7% and protein yield by 2%, but grain protein concentration would be reduced by -1.1 percentage points, representing a relative change of -8.6%. Climate change adaptations that benefit grain yield are not always positive for grain quality, putting additional pressure on global wheat production.

From ancient to old and modern durum wheat varieties: interaction among cultivar traits, management, and technological quality.

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. © 2018 Society of Chemical Industry.

Genetic variation for the duration of pre-anthesis development in durum wheat and its interaction with vernalization treatment and photoperiod.

A recombinant inbred durum wheat population was grown under three contrasting regimes: long days following vernalization (LDV), long days without vernalization (LD), and short days following vernalization (SDV). The length of several pre-anthesis stages and the number of leaves and the phyllochron were measured. Different groups of genes were involved in determining the phenology in the three treatments, as demonstrated by a quantitative trait locus (QTL) analysis. The length of the period required to reach the terminal spikelet stage was correlated with the time to anthesis only in the case of LDV- and LD-grown plants where the timing of anthesis depended on the final leaf number. However, for SDV-grown plants, anthesis date was more dependent on the length of the period between the terminal spikelet stage and anthesis and was independent of leaf number. The involvement of the phyllochron in determining the duration of pre-anthesis development was also treatment-dependent. QTL mapping of the various flowering time associated traits uncovered some novel loci (such as those associated with the phyllochron), in addition to confirming the presence of several well-established loci.

Clipping Effect on the Grain Nitrogen and Protein Fractions of Ancient and Old Wheats Grown in a Mediterranean Environment.

This study is the first to assess the effects of clipping, cultivar, season, and their interactions on the protein composition of six old and ancient wheat cultivars (n = 6). For this, nitrogen content, the proportion of wheat protein fractions, and the molecular weight distribution of the extractable and unextractable glutenin polymers were investigated as a function of cultivar and clipping in two consecutive seasons. The relationships between genotypic variation in grain nitrogen and protein fraction content under clipping and non-clipping conditions were also assessed. Clipping delayed and shortened the grain filling period of all of the cultivars. The protein composition of some cultivars behaved differently to clipping due to differences in the environmental conditions of S1 (exceptional dry season) and S2 (rainy season). In S1, clipping decreased the ratio of gliadins over glutenins (GLI/GLU) (<1) of Cappelli and Giovanni Paolo, while in S2, clipping improved the GLI/GLU of Giovanni Paolo, Monlis, and Norberto. The unextractable polymeric proteins were not affected by clipping. Khorasan was shown to be indifferent to clipping in S1 and S2. These results suggest that it is possible to have ancient/old wheats suitable for a dual-purpose system, in different climatic conditions, while maintaining good grain quality traits. The increased market demand for ancient and old wheats presents an economic opportunity for farmers who adopt the dual-purpose technique to cultivate these resilient crops again and increase their profit margins and revenues.

Environmental conditions affect semolina quality in durum wheat (Triticum turgidum ssp. durum L.) cultivars with different gluten strength and gluten protein composition.

BACKGROUND: Sowing time may impact semolina and pasta cooking quality by changing the environmental conditions during grain filling. The effect of an optimum and a delayed sowing time on semolina quality was studied by comparing six cultivars under irrigation, in order to isolate temperature from drought effects. RESULTS: Protein content was higher in the old cultivars and in the late sowings, according to the number of days with temperature between 30 and 40 °C during ripening. Gluten index increased as temperature rose to a threshold of about 30 °C, then decreased under higher temperatures. Mixograph parameters were less sensitive to high temperatures. Gliadin:glutenin correlated with gluten strength. Spaghetti firmness and protein content were positively correlated independently of sowing date. Cultivars Trinakria and Cappelli had the highest spaghetti firmness (900 and 828 g). CONCLUSIONS: Late sowings may represent a way of increasing pasta cooking quality whenever they place grain filling under thermal conditions able to increase protein percentage, although the accompanying decrease in yield may represent a drawback in environments prone to drought stress during ripening. The lower protein percentages of modern durum wheat cultivars under conventional sowing times results in a lower pasta cooking quality despite higher gluten strength.

Is the Technological Quality of Old Durum Wheat Cultivars Superior to That of Modern Ones When Exposed to Moderately High Temperatures during Grain Filling?

The growing interest in old durum wheat cultivars, due to enhanced consumer attention on healthy, traditional products and low-input agricultural systems, partly relies on their different quality characteristics compared to modern cultivars. Nine Italian durum wheat cultivars from different breeding periods were compared in two late-sown (January) field trials in order to subject their grain filling period to high temperatures similar to those expected in the future. Late sowing moved anthesis forward by about 10 days and increased the mean temperature during grain filling by 1.3 °C compared to that obtained when using the common sowing period of November-December. In these conditions, old cultivars were on average less productive than modern ones (2.36 vs. 3.54 tons ha-1, respectively), had a higher protein percentage (13.8% vs. 11.1%), a lower gluten index (24.3% vs. 56.3%), and a lower alveographic W (baking strength) (64 vs. 100 J 10-4). The differences were partly associated to variations in the gliadins:glutenins ratio. It depended on the genotype whether the grain and semolina protein percentage and gluten strength compensated one another in terms of alveographic indices to give the dough a strength similar to that of the modern cultivars in the range of moderately high temperatures, which resulted from delayed sowing. Further studies aimed at exploring the genetic variability of quality traits in the large genetic pool represented by the several Italian old and intermediate durum wheat cultivars still available are therefore advisable.

N Partitioning between Gluten Fractions in a Set of Italian Durum Wheat Cultivars: Role of the Grain N Content.

Grain protein content constitutes a key quality trait for durum wheat end-products and may also impact grain protein composition. A total of sixteen durum wheat cultivars were analyzed in a field trial during two seasons at two nitrogen (N) levels to evaluate whether and to what extent the variation in total grain N was associated with variation in the quantity of the various protein fractions and grain quality parameters. Genotypic variation in grain N content correlated with the variation in the content of all three protein fractions, although the strength of the correlation with gliadin and albumin-globulin was higher than that with glutenins. Genotypic variation in gliadin and glutenin content was more tightly correlated with the variation in the sulfur (S)-rich protein groups than with the S-poor protein groups and subunits. The variation in the percentage of unextractable polymeric proteins (UPP%) among genotypes was independent of their glutenin allelic composition. The significant genotypic differences in UPP% and in the ratios between protein groups and subunits were not influenced by the corresponding variation in grain N content. The final grain N content can only account for part of the variation in quality parameters and in the partitioning of total grain N between protein fractions since genotypic differences other than grain N content also contribute to these variations.

Environmental and Genetic Variation for Yield-Related Traits of Durum Wheat as Affected by Development.

Phenology has a profound effect on adaptation and productivity of crops. The impact of phenology on tillering and fertility traits of durum wheat (Triticum turgidum L. subsp. durum Desf.) was evaluated with the aim of specifying which group of flowering genes (Vrn, Ppd, or eps) was involved in their control. A recombinant inbred line population was grown under four contrasting conditions of vernalization and daylength. Phenotyping was carried out according to robust phenological models dissecting both phenological and yield related traits. Whole-genome profiling was performed using the DArT-Seq technology. The genetic variability for tillering was mainly related to the genetic variability for vernalization sensitivity, as shown by the many quantitative trait loci (QTLs) identified in non-vernalized plants associated to both tillering and phenological traits. No effects of photoperiod sensitivity on spikelet number were detected in short-day-grown plants, apparently because of limited genetic variability in photoperiod sensitivity of the population. Earliness per se was involved in control of spikelet number via final leaf number, with these traits genetically correlated and sharing some QTLs. Chaff weight and number of kernels per g chaff were negatively associated and related to anthesis date under most conditions. QTL mapping uncovered novel loci involved in phenological control of tillering and fertility traits, and confirmed the presence of several well-established loci. Phenotyping of both phenology and kernel number according to a robust physiological model amplified the possibility of identifying genetic factors underlying their variations. Also, isolating known flowering gene cues by manipulation of environmental conditions provided the opportunity for each group of genes to be expressed without confounding effects of the others. This information helps to predict the consequences of either genetic manipulation of flowering genes and changes in environmental conditions on the potential yield of durum wheat.