Grain concentrations of protein and mineral nutrients in a large collection of spelt wheat grown under different environments

A large number of spelt wheat genotypes (ranging from 373 to 772) were evaluated for grain concentrations of protein and mineral nutrients under 6 different environments. There was a substantial genotypic variation for the concentration of mineral nutrients in grain and also for the total amount of nutrients per grain (e.g., content). Zinc (Zn) showed the largest genotypic variation both in concentration (ranging from 19 to 145 mg kg⁻¹) and content (ranging from 0.4 to 4.1 μg per grain). The environment effect was the most important source of variation for grain protein concentration (GPC) and for many mineral nutrients, explaining between 37 and 69% of the total sums of squares. Genotype by environment (G × E) interaction accounted for between 17 and 58% of the total variation across the minerals. GPC and sulfur correlated very significantly with iron (Fe) and Zn. Various spelt genotypes have been identified containing very high grain concentrations of Zn (up to 70 mg kg⁻¹), Fe (up to 60 mg kg⁻¹) and protein (up to 30%) and showing high stability across various environments. The results indicated that spelt is a highly promising source of genetic diversity for grain protein and mineral nutrients, particularly for Zn and Fe.     

Molecular characterization of storage proteins for selected durum wheat varieties grown in different environments

The variations of the amounts of individual high molecular weight glutenin subunits (HMW-GS), of the ratios HMW-GSy to HMW-GSx and HMW-GS to low molecular weight glutenin subunits (LMW-GS) and of protein content were evaluated for eight durum wheat cultivars in two regions using four fertilizer combinations during two successive years. All measured parameters showed significant variation with genotypes (G), environments (E) and fertilizers (F). The interaction E × G × F was highly significant for glutenin amount variation. Amongst cultivars possessing HMW-GS 20, landraces seem to better value the N-fertilizer use for the accumulation of HMW-GSy than high yielding cultivars. Both HMW-GSy to HMW-GSx and HMW-GS to LMW-GS ratios were found to be positively correlated (p < 0.05) with total protein content.     

Phytate and mineral elements concentration in a collection of Italian durum wheat cultivars

Mineral deficiencies are prevalent in human populations and the improvement of the mineral content in cereal products represents a possible strategy to increase the human mineral intake. Nevertheless, most of the inorganic phosphorus (P_i) present in mature cereal seeds (40–80%) is stored as phytate, an anti-nutritional factor that forms complexes with minerals such as Ca, Mg, Zn and Fe reducing their bioavailability. The present study was undertaken: (i) to determine the variation in phytate and mineral concentrations in the whole grains of 84 Italian durum wheat (Triticum durum Desf.) cultivars representative of old and modern germplasm; (ii) to estimate the magnitude of genotype × environment interaction effects; and (iii) to examine the interrelationships among mineral concentrations in durum wheat with the final aim to identify superior durum wheat cultivars that possess low phytate content and high concentration of mineral elements in their whole-wheat flour. The cultivars were grown in field trials during 2004–2005 at Foggia, Italy and during 2005–2006 at Foggia and Fiorenzuola d’Arda—Southern and Northern Italy. The phytate content was estimated indirectly by using a microtitre plate assay evaluating the P_i absorbance at 820 nm, while the Cu, Fe, Mn, Ca, K, Mg, Na and Zn mineral contents were determined by ICP/OES. The contents of Zn and Fe across years and locations ranged from 28.5 to 46.3 mg/kg for Zn with an average of 37.4 mg/kg and from 33.6 to 65.6 mg/kg for Fe with an average of 49.6 mg/kg. P_i grain content was between 0.46 and 0.76 mg/g showing a positive correlation with all minerals except Cu and Zn. Although breeding activity for Fe and Zn would be difficult because G × E interaction is prevalent, multi-location evaluation of germplasm collection help to identify superior genotypes to achieve this objective. The results here reported open the possibility of designing a specific breeding program for improving the nutritional value of durum wheat through the identification of parental lines with low-P_i and high minerals concentration in whole grains.     

Variation in gluten quality parameters of spring wheat varieties of different origin grown in contrasting environments

The aim of this study was to investigate variation in protein content and gluten viscoelastic properties in wheat genotypes grown in two mega-environments of contrasting climates: the southeast of Norway and Minnesota, USA. Twelve spring wheat varieties, nine from Norway and three HRS from Minnesota, were grown in field experiments at different locations in Norway and Minnesota during 2009–2011. The results showed higher protein content but lower TW and TKW when plants were grown in Minnesota, while the gluten quality measured as Rmax showed large variation between locations in both mega-environments. On average, Rmax of the samples grown in Minnesota was higher than those grown in Norway, but some locations in Norway had similar Rmax values to locations in Minnesota. The data showed inconsistent relationship between the temperature during grain filling and Rmax. Our results suggest that the weakening effect of low temperatures on gluten reported in this study are caused by other environmental factors that relate to low temperatures. The variety Berserk showed higher stability in Rmax as it obtained higher values in the environments in Norway that gave very weak gluten for other varieties.     

Genetic control of processing quality in a bread wheat mapping population grown in water-limited environments

End-use quality of bread wheat (Triticum aestivum L.) is affected by both genetic and environmental variation. Current understanding of the genetic control of wheat quality traits is mainly based on genetic experiments conducted using grain produced in favourable conditions. The objective of this research was to extend the genetic analysis of these traits by using grain produced in water-limited environments. Grain samples harvested from a mapping population grown in field experiments at two locations in Australia were used to assess characteristics of the grain, flour, dough and bread. Quantitative trait loci (QTLs) were mapped. The parents of the population, RAC875 and Kukri, differ at several loci that are known to affect grain quality or plant phenology. Of these, a high-molecular-weight glutenin locus (Glu-B1) affected dough properties, the puroindoline-encoding Ha locus affected grain hardness, flour and loaf properties and a photoperiod response locus (Ppd-D1) affected flour extraction and protein content. Similarly, several previously reported quantitative trait loci (not associated with specific genes) also had effects in the stress environments used here. In addition, novel loci were detected for bread wheat quality traits; their effects may be specific to materials grown in water-limited environments.     

Grain yield,starch, protein,and nutritional element concentrations of winter wheat exposed to enhanced UV-B during different growth stages

In order to alleviate the damage of UV-B on plants, it is important to determine at which growth stages are plants more sensitive to enhanced UV-B. The objective of the study was to evaluate the effects of UV-B on wheat yield and quality during different growth stages. Enhanced UV-B during heading, flowering and the whole growth stages (UCK, from seedling to grain filling) decreased yield by 6.6, 4.4 and 9.6%, respectively. Protein content in grain was decreased by enhanced UV-B during flowering and UCK over the control. Amylose, amylopectin and total starch content were not affected by UV-B treatments. UCK treatment resulted in a decrease of nitrogen (N), phosphorus (P) and iron (Fe) concentrations, while zinc (Zn) and manganese (Mn) concentrations increased. Enhanced UV-B during tillering, heading and flowering stages reduced Fe concentration, but increased Mn, copper (Cu) and Zn (except for flowering) concentrations. The results indicated that the changes in wheat yield and quality induced by enhanced UV-B during the whole growth stage were probably from the effects of UV-B radiation during heading and flowering stages. Therefore, to better defend the damage of UV-B to wheat, some methods should be undertaken during heading and flowering stages.     

Molar fractions of high-molecular-weight glutenin subunits are stable when wheat is grown under various mineral nutrition and temperature regimens

Molar fractions of the high-molecular-weight glutenin subunits (HMW-GS) were determined for flour from bread wheat (Triticum aestivum L. cv Butte86) produced under 13 different combinations of temperature, water and mineral nutrition. Albumins, globulins and gliadins were removed from the flour by extraction with 0.3 M NaI in 7.5% 1-propanol. Total HMW-GS were recovered by extracting the remaining protein with 2% SDS and 25 mM DTT. Individual HMW-GS were then separated and quantified by RP-HPLC. Constant molar fractions for the five HMW-GS were maintained under all environmental conditions, despite large differences in duration of grain fill, total protein per grain, flour protein percentage, and total HMW-GS per grain. Similar molar fractions were found for five other US wheat varieties. The Bx7 subunit accumulated to the highest level at 30% of total HMW-GS. The Dx and Dy subunits were present in smaller but nearly equal proportions, 22% and 23%, respectively, and the Ax and By subunits were the least abundant, 14% and 12%, respectively. Although the amounts of HMW-GS per unit of flour are strongly affected by environment, the different subunits respond so similarly to external conditions that their final proportions appear to be determined mainly by genetic factors.     

Variation in mineral micronutrient concentrations in grain of wheat lines of diverse origin

150 lines of bread wheat representing diverse origin and 25 lines of durum, spelt, einkorn and emmer wheat species were analysed for variation in micronutrient concentrations in grain. A subset of 26 bread wheat lines was grown at six sites or seasons to identify genetically determined differences in micronutrient concentrations. Substantial variation among the 175 lines existed in grain Fe, Zn and Se concentrations. Spelt, einkorn and emmer wheats appeared to contain higher Se concentration in grain than bread and durum wheats. Significant differences between bread wheat genotypes were found for grain Fe and Zn, but not Se concentration; the latter was influenced more by the soil supply. Grain Zn, but not Fe, concentration correlated negatively with grain yield, and there was a significant decreasing trend in grain Zn concentration with the date of variety release, suggesting that genetic improvement in yield has resulted in a dilution of Zn concentration in grain. Both grain Zn and Fe concentrations also correlated positively and significantly with grain protein content and P concentration, but the correlations with kernel size, kernel weight or bran yield were weak. The results from this study are useful for developing micronutrient biofortification strategies.     

Effect of mineral nutrients on spot blotch severity in wheat,and associated increases in grain yield

Spot blotch, caused by Cochliobolus sativus, is a serious disease of wheat (Triticum aestivum L.) in the warm lowlands of South Asia. A field study was conducted using two wheat varieties (Bhrikuti and Sonalika) during the 2001 and 2002 wheat seasons in Rampur, Nepal, to determine the effect of nitrogen, phosphorus, potassium, and chlorine fertilization on reducing spot blotch severity in wheat, and its associated increase in grain yield. Application of N alone reduced spot blotch severity by 8% in 2002. Phosphorus fertilization had no effect on spot blotch development. The balanced application of N, P, and K reduced disease severity by 15 and 22% in 2001 and 2002, respectively. Application of KCl as well as CaCl₂ reduced spot blotch severity, but the former caused 11% greater reduction than the latter. The two varieties responded differently to the mineral nutrients’ effect on spot blotch severity, suggesting the nutrients’ importance in cultivar selection when considering the effect of soil fertility on susceptibility to foliar diseases. The lower disease severity and higher grain yield observed after the application of KCl compared to CaCl₂ showed that KCl should be used on K-deficient soils in the warmer wheat growing regions of South Asia where spot blotch is a serious perennial wheat disease in intensive rice–wheat cropping systems.     

Grain yield,zinc efficiency and zinc concentration of wheat cultivars grown in a zinc-deficient calcareous soil in field and greenhouse

Field experiments were carried out to study grain yield, zinc (Zn) efficiency and concentrations of Zn in shoot and grain of 37 bread wheat (Triticum aestivum) and three durum wheat (Triticum durum) cultivars grown in a Zn-deficient calcareous soil with (23 kg Zn ha⁻¹), and without, Zn fertilization in 1993–1994 and 1994–1995. The same Zn-deficient soil was used in greenhouse experiments to study shoot dry weight, Zn efficiency and shoot Zn concentrations of 21 bread and three durum wheat cultivars (same cultivars used in the field experiments). Zinc fertilization of cultivars in the field enhanced grain yield on average by 30% in both years. Increases in grain yield to Zn fertilization varied substantially between cultivars from 8% to 76%. Accordingly, there was large variability in Zn efficiency of cultivars, expressed as the ratio of grain yield or shoot dry-matter yield produced under Zn deficiency compared to that under Zn fertilization. On average, Zn efficiency values ranged from 57% to 92% for grain yield in field experiments and from 47% to 83% for shoot dry weight in greenhouse experiments. Most of the cultivars behaved similarly in their response to Zn deficiency in the field and greenhouse. The cultivars selected from local landraces had both, a high Zn efficiency and high yield under Zn-deficient conditions. The bread wheat cultivars, improved for irrigated conditions, had generally low Zn efficiency and low yield, both in the field and greenhouse. All durum wheat cultivars in this study also showed low levels of Zn efficiency, grain yield and shoot dry weight under Zn deficiency. Overall, there was no relation between Zn efficiency values and Zn concentrations in grain or shoot dry matter. The results presented here demonstrate the existence of substantial variation in Zn efficiency among wheat cultivars, particularly bread wheat cultivars, and suggest that wheat landrace populations are a valuable source of genes to improve high Zn efficiency of wheat for Zn-deficient soils.     

Effects of N and K fertilizers on durum wheat quality in different environments

Eight genotypes from two different genetic pools (high yielding varieties and landraces) were assessed for grain yield (GY) and for five quality traits: protein content (P), thousand kernel weight (TKW), yellow berry (YB), gluten content (G_c) and gluten index (G_i) in sub-humid and semi-arid areas using four combinations of nitrogen and potassium fertilizers during two cropping seasons. Genotype × Environment × Fertilizers (G × E × F) was significant only for protein content (p < 0.05); and E × F was found significant (p < 0.05) for all parameters. Greater quality related traits expression was noted in the semi-arid areas for both genetic pools. Excessive rainfall in semi-arid areas resulted in gluten elasticity reduction. N-fertilizers seemed to enhance protein content and to reduce thousand kernel weight. K-fertilizer, might enhance the increase in both proteins and thousand kernel weight in favorable growing conditions of water availability. Semolina yielding ability was higher in landraces as compared to high yielding varieties particularly using recommended fertilizer management. This group of cultivars showed superiority over high yielding cultivars for quantitative quality parameters.     

Nutritive value of wheat grown under organic and chemical systems of farming

1) 21±2 day old LACA mice, derived from litter sizes 8–10 and maintained at 22.2±0.6°C and 58.0±1.5% relative humidity, were housed as 5 or 5 per box and fed 1 of 4 experimental diets or a control diet.2) The experimental diets were made from flour produced from wheat grown on the Organic, Mixed or Stockless (chemical) Sections of the experimental farms at Haughley, or a neighbouring farm using intensive farming methods. The flour was supplemented with vitamins and minerals and made into biscuits. In 2 of the 5 experiments the diets were also supplemented with casein. The control diet was Spratts Laboratory diet 1, formerly known as Laboratory Small Animal Diet (Autoclaved).3) At 65±2 days old the mice were put together as monogamous pairs and their subsequent breeding performance monitored.4) The litter size at birth, the weaning ability of the mother, and the time interval between successive litters were recorded. Separate analyses of variance performed on the data for each parameter for each experiment failed to detect a difference in the performance of the animals receiving wheat grown on the 3 Sections of the experimental farms.5) All offspring were sexed and weighed at weaning. Analyses of variance showed a significant difference in these weights. The animals derived from parents receiving wheat from the Mixed Section were consistently heavier than those derived from parents receiving wheat from the other Sections of the experimental farms. This evidence suggests that agricultural practise can influence the nutritional value of crops.     

Grain cadmium and zinc concentrations in wheat as affected by genotypic variation and potassium chloride fertilization

Thirteen bread wheat (Triticum aestivum L.) and two durum wheat (Triticum turgidum L. var. durum) cultivars were grown over six site-years to identify differences in grain Cd and Zn concentrations, as affected by genotypic variation and soil application of potassium chloride (KCl) fertilizer. Application of KCl fertilizer did not consistently affect grain Cd concentration of wheat cultivars, but increased average grain yield and decreased average grain Zn in 4 of 6 site-years. However, soil type and year had significant effects on grain Cd and Zn, indicating a strong environmental effect on grain quality. Grain concentrations of Cd and Zn were generally lower for the clay loam (CL) than the fine sandy loam (FSL) soils. The wheat cultivars showed significant genotypic differences in grain concentrations of Cd and Zn, suggesting the potential of breeding to reduce Cd and increase Zn concentrations in grain. The two durum cultivars contained high concentrations of Cd but not Zn compared to the bread wheat. The interaction between cultivars and site-years was significant for grain Zn, but not for grain Cd, suggesting that grain Cd is a more stable trait than grain Zn across environments. Grain Zn and Cd were not related to each other but they both correlated negatively with grain yield. The lack of relationship between Zn and Cd suggests that breeding for enhanced Zn concentration can be attained without necessarily affecting grain Cd concentration. The negative relationship between Cd and Zn concentration and dry matter yield was likely the result of biological dilution, suggesting that genetic improvement leading to increased yield may concurrently decrease mineral concentration. Results of this study are useful to improve the mineral composition of wheat used for human consumption through the development of cultivars and use of agronomic management practices that increase Zn and/or reduce Cd concentrations in wheat grain.     

Winter wheat genotypes under different levels of nitrogen and water stress: Changes in grain protein composition

Hard white winter wheat with superior and consistent quality is preferable for Asian markets. This study investigated the combined influences of moisture deficit during grain-fill and N management on protein quality, dough rheological properties, and protein molecular weight distributions in soft and hard winter wheats. Genotypes were grown under an irrigation gradient and two N-fertilization levels. Grain polyphenol oxidase (PPO) activity, SDS sedimentation, and Mixograph analyses were evaluated. Flour protein composition was characterized using SE-HPLC. Moisture stress during grain-fill increased flour protein content. N fertilization increased flour protein content. No significant correlation was found between flour protein and PPO. Changes in protein composition were related to general increases in protein content, regardless if the result of reduced irrigation or increased fertilization rate. The percentage of monomeric proteins increased more than the polymeric proteins as flour protein increased. Similarly, SDS sedimentation volume increased as a function of protein content. As expected, subunit GluD1 5+10 was associated with larger sedimentation volume and higher dough strength in genotypes as compared to those with subunit GluD1 2+12. Biplot analyses showed that genotypes of similar protein quality and composition responded similarly to N and irrigation treatments.     

Evaluation of CIMMYT conventional and synthetic spring wheat germplasm in rainfed sub-tropical environments. I. Grain yield

Hexaploid spring wheat (Triticum aestivum L.) germplasm from CIMMYT's breeding program in Mexico has assisted wheat improvement in Australia, particularly in the north-eastern region where terminal drought frequently reduces grain yield. A total of 273 conventional hexaploid and derived synthetic hexaploid spring wheats from CIMMYT, along with 15 locally adapted Australian cultivars (Oz lines), were evaluated for grain yield over four years in a total of 27 environments in Australia's north-eastern wheat region. The CIMMYT conventional spring wheats were from a Seri/Babax recombinant inbred line population (SB lines), elite entries from an International Adaptation Trial (IAT lines) introduced to Australia between 1999 and 2004 and from CIMMYT screening nurseries introduced to Australia in 2004–2005 (SW lines). Synthetic wheats (SYN lines) were also from these nurseries as well as from a separate program of synthetic wheat introductions to Australia over 2001–2004.     

不同SDS-PAGE分离胶浓度条件下大豆贮藏蛋白亚基的分辨效果

采用SDS-PAGE浓缩胶浓度为5%,分离胶浓度分别为9%、10%、11%、12%、13%的凝胶系统,探讨不同分离胶浓度条件下大豆籽粒主要贮藏蛋白(7S和11S组分)亚基的分辨效果.结果表明,分离胶浓度大小对大豆贮藏蛋白(7S和11S组分)亚基电泳图谱分辨率的影响非常明显.分离胶浓度为9%和10%时,7S组分亚基(α'、α和β)分辨效果较好;分离胶浓度为13%时,11S组分各亚基(A3、A4A2、A1aA1b、A5、B3、B1aB1bB2和B4)分辨效果较好.如需获得较好的7S和11组分亚基综合分辨效果,以分离胶浓度为12%的凝胶系统为佳.     

Impact of late-season N fertilisation strategies on the gluten content and composition of high protein wheat grown under humid Mediterranean conditions

The rise in high protein common wheat in humid Mediterranean areas has determined a need to compare specific and effective nitrogen (N) fertilisation protocols in order to increase their end-use value. The aim of the work was to assess the impact of late-season N fertilisation strategies on grain yield and protein content (GPC), gluten fraction composition, and rheological traits. Different applications and types of fertiliser (soil applied ammonium nitrate, soil applied urea, foliar applied urea and a foliar applied commercial fertiliser) were distributed at the same rate (30 kg N ha⁻¹) in a field experiment in NW Italy, during three growing seasons. A control without any late-season N fertilisation was also considered. All the treatments received 130 kg N ha⁻¹ as ammonium nitrate (AN), which was split between tillering and the beginning of the stem elongation growth stages.None of the compared late-season N fertilisations significantly affected canopy greenness and stay green duration during the grain filling period, or the grain yield, test weight, and thousand kernel weight, although the foliar application significantly increased foliage burning (+9.8%). The late application of N consistently increased GPC (+1.1%) and dough strength (W, +21%) in the different growing seasons. The type of fertilisation strategies clearly affected the gluten content and rheological parameters: AN was more effective than urea as a soil top-dressed applied fertiliser in increasing W (+10%), as a result of a higher rise in the GPC content (+0.5%) and extensibility (L, +11%). The foliar application at anthesis, at the same N rate, led to a comparable GPC and W with those of the soil top-dressed granular fertiliser. Only a weak effect of granular urea on y/x type HMW was observed for the gluten composition. Conversely, a notable influence of year was observed (i.e. GS/Glia and y/x type HMW), which in turn resulted in a significant impact on W and P and on the aggregation time and aggregation energy.This study offers a further contribution to the improvement of specific N fertilisation strategies in order to enhance the wheat quality according to its end-use value.     

Optimal numbers of environments to assess slopes of joint regression for grain yield,grain protein yield and grain protein concentration under nitrogen constraint in winter wheat

Plant breeders are interested in rationally reducing the number of testing environments for breeding new genotypes adapted to diverse conditions. One way to characterize the adaptation of a genotype is to use the joint regression model. Our objectives were to estimate the stability for grain yield (GY), grain protein yield (GPY) and grain protein content (GPC) of a set of wheat genotypes grown under varying nitrogen conditions and then to determine optimal numbers of environments for assessing the slopes of joint regression.     

Determination of phenolic acid concentrations in wheat flours produced at different extraction rates

High-performance liquid chromatography (HPLC) was used to determine the distribution of phenolic acids in wheat flours produced from five milling extraction rates ranging from 60% to 100% in four cultivars sown in two locations in the 2008–2009 season. Considerable variation was observed in free and bound phenolic acids, and their components in flours with different extraction rates. Most phenolic acids, including the component ferulic, were present in the bound form (94.0%). Ferulic (51.0%) was the predominant phenolic acid in wheat grain, and caffeic (22.8%) and p-coumaric (17.6%) acids were abundant. The phenolic acids and their components were all significantly influenced by effects of cultivar, milling, location, and cultivar × milling interaction, with milling effect being the predominant. The proportions of phenolic compounds varied considerably among milling extractions and cultivars, and their levels depended on both initial grain concentrations and on selection of milling extraction that was incorporated into the final product. The grain phenolic acid concentrations determined ranged from 54 μg g⁻¹ in flour produced at 60% extraction rate to 695 μg g⁻¹ in flour produced at 100% extraction rate, indicating their higher concentrations in bran associated with cell wall materials. Therefore, wholemeal wheat products maximize health benefits and are strongly recommended for use in food processing.