Genetic changes in durum wheat yield components and associated traits in Italian and Spanish varieties during the 20th century

Twelve field experiments comparing 24 durum wheat varieties from three periods—old (<1945), intermediate (1950–1985) and modern (1988–2000)—were carried out in order to ascertain the advances made in durum wheat yield components and related traits in Italian and Spanish germplasm. Grain yield improvements were based on linear increases in the number of grains per m² and harvest index, while grain weight and biomass remained unchanged. Yield per plant increased at a rate of 0.36 and 0.44% y⁻¹ and the number of grains per m² improved by 39% and 55% in Italian and Spanish varieties, respectively. The mean rate of increase in the number of grains per m² was 0.55% y⁻¹. Plants per m², spikes per plant and grains per spike contributed 20%, 29% and 51%, respectively, to the increase in the number of grains per m². The enhance of the number of grains per m² was due to the greater grain set in the modern varieties, since the number of spikelets per spike remained unchanged. Harvest index increased overall by 0.48% y⁻¹ (0.40 and 0.53% y⁻¹ in Italian and Spanish varieties, respectively). Plant height was the trait that suffered the most dramatic changes (it decreased at a rate of −0.81% y⁻¹, with little difference between the varieties of the two countries), as consequence of the presence of the Rht-B1 dwarfing gene. Harvest index and plant height, which were the traits that most contributed to discriminating between periods, remained unchanged from 1980 to 2000. The higher rates of improvement in Spain are discussed in the context of the contrasting strategies followed to improve durum wheat yield in the two countries.     

Genetic variation of wheat glutenin subunits between landraces and varieties and their contributions to wheat quality improvement in China

Glutenin, one of major factors effecting bread-making quality, is comprised of a mixture of polymers, viz. high-molecular-weight glutenin subunits (HMW-GSs) and low-molecular-weight glutenin subunits (LMW-GSs). Understanding variation among these glutenin subunits can help breeders determine allelic effects on specific quality traits and to use them as genetic markers. The HMW-GS and LMW-GS compositions of 390 landraces and 225 released varieties were analyzed by SDS–PAGE, and some quality traits, including Zeleny sedimentation volume, dough development time, stability time and strengths, were evaluated. The results indicated that 17 and 13 HMW-GSs were present in landraces and released varieties, respectively. For LMW-GS (Glu-A3 and Glu-B3 loci), 12 alleles were found in both landraces and released varieties. Total allelic richness at glutenin loci in landraces was higher, but the genetic dispersion index was lower than in released varieties. Two new subunit combinations 6 + 16 and 7 + 22, and some rare subunits 6 + 9*, 23 + 22, 6* + 8, 7 and 8, were identified in landraces and released varieties. The Glu-D1 and Glu-B3 loci had significantly positive effects. Based on the comparison of the effect of each subunit on quality, it was concluded that subunits 1 at Glu-A1, 13 + 16, 17 + 18 and 6 + 16 at Glu-B1, 5 + 10 at Glu-D1, Glu-A3b at Glu-A3 and Glu-B3d at Glu-B3 contributed larger positive effects on bread-making quality than alternative alleles. From this study, genetic materials with strong gluten and good quality were identified in landraces that did not carry the 1BL.1RS translocation.     

Complexity of the Gli-A3 locus in bread wheat

Two bread wheat cultivars, ‘Ariana 8’ and ‘Cajeme 71’, and 129 F₂, grains from the cross between them were analysed for gliadin composition. Two monodimensional (A-PAGE and SDS-PAGE) and two different two-dimensional (SDS-PAGE x SDS-PAGE and A-PAGE x SDS-PAGE) electrophoretic methods were used. Parents differed at the Gli-Al locus, detected by A-PAGE. The SDS-PAGE of the aqueous ethanol extractable protein under nonreduced conditions showed two bands of ‘Ariana 8’ and one of ‘Cajeme 71’, encoded by genes located 22 cM from the Gli-Al locus, and therefore, located at the Gli-A3 locus. This locus has been considered to contain genes coding for ω-gliadins alone. The two-dimensional maps of the parents showed that one band from ‘Ariana 8’ was an ω-gliadin, but the other two bands, one from each parent, were γ-gliadins. Results obtained indicated that GH-A3, like Gli-Al, is a complex locus coding for both ω-and γ-gliadins.     

Genetic gain in yield and changes associated with physiological traits in Brazilian wheat during the 20th century

The objective of this study was to characterize physiologically wheat cultivars released in different decades and identify selection criteria for the continued genetic progress in Brazil. Ten cultivars released from 1940 up to 2009 were tested during 2010 and 2011 crop seasons. The following traits were evaluated: grain yield (GY), thousand-kernel weight (TKW), grain number per m⁻² (GN), plant height (PH), harvest index (HI), above-ground biomass (BIO), relative Chlorophyll content and leaf gas exchanges. The increase in grain yield was 29 kg ha⁻¹ yr⁻¹ a genetic gain of 0.92%, annually. Grain yield improvement was largely associated with HI (0.94^**), number of grains m⁻² (0.93^**), BIO (0.88^**) and reduced PH (−0.93^**). The post-anthesis Chlorophyll content, stomatal conductance and pre/post-anthesis photosynthetic rate were positively correlated with GY. Genetic gains of Brazilian wheat are mainly related to the increases of HI, GN, and BIO. These improvements were achieved by reducing PH and raising gas exchanges and chlorophyll content.     

Breeding progress in morpho-physiological,agronomical and qualitative traits of durum wheat cultivars released in Italy during the 20th century

Fourteen durum wheat (Triticum durum Desf.) cultivars introduced in Italy between 1900 and 1990 were grown for 2 years (2001 and 2002) at Foggia (Italy) in field trials with three agronomic treatments in order to assess the genetic improvement in agronomic and qualitative parameters. The traits were measured in the field to describe the biomass production and its partitioning to the grain, the phenological behaviours and the photosynthetic properties. Grain protein content, alveograph's W-index, carotenoid pigments content, ash content and the glutenin and gliadin subunit compositions were then measured to assess grain quality. The results showed that differences in agronomic traits among durum wheat cultivars released in Italy in the last century are generally similar to differences observed in hexaploid wheat, with an annual genetic yield gain of 19.9 kg ha⁻¹ year⁻¹. The genetic gain was most clearly associated with a higher kernels number m⁻² indicating a larger grain-sink size and a higher number of spikes m⁻². The gradual reduction in plant height associated with an increased harvest index has represented the main breeding goal with an effect on the sink capacity and on the biomass partitioning. The progressive incorporation into recent cultivars, of favourable alleles (7 + 8 glutenin subunit composition) coding for superior quality subunits reflects the improvement in pasta making quality of the recent genotypes.     

影响面条品质的小麦品质性状及其QTLs定位的研究进展

本文总结了国内外近几年关于面条品质的研究资料,对影响面条品质的小麦品质性状,包括蛋白质的含量、麦谷蛋白亚基组成、直链淀粉的含量、淀粉特性、Waxy蛋白、面筋的含量、沉淀值、面团的主要特性等进行了概述,对这些小麦品质性状在染色体上QTLs定位的研究情况进行了综述,以期为面条专用小麦的选育和我国面条加工业的发展提供科学的参考。     

黄淮麦区小麦品种高分子量谷蛋白亚基及亚基组成与品质性状关系的研究

对黄淮麦区的77个不同小麦品种高分子量谷蛋白亚基及亚基组成与蛋白质含量和沉降值之间的关系进行了研究,结果表明:Glu-1三位点的亚基等位变异共有13种,A1位点亚基1出现频率最高,为71.05%,亚基2*最低,仅为3.94%;B1位点亚基7 9和7 8相对频率最高,分别为43.42%和31.58%,亚基17 18出现频率最低,为1.32%;D1位点亚基2 12出现频率最高,为52.63%,亚基4 12最低,为3.16%。值得注意的是,优质亚基14 15和5 10,在B1和D1位点分别出现了较高的频率,为10.53%和31.21%。三位点亚基对蛋白质含量的效应分别表示为:1≥2*>Null,14 15≥17 18≥7 8>7>7 9>20≥6 8,5 10>2 12≥4 12。对沉降值的效应分别表示为:2*≥1>Null,14 15≥7 8>7≥17 18>7 9≥20>6 8,5 10>2 12≥4 12。在蛋白质含量水平上,亚基组成1、14 15、2 12,1、7 8、5 10,1、7、5 10和1、7 9、5 10相对较高;在沉降值水平上,亚基组成1、7 8、5 10和1、14 15、2 12相对较高。因此,研究认为三位点分别为1或2*、7 8或14 15、5 10是品质优良的最佳亚基组合。     

Detection of QTLs for bread‐making quality in wheat using a recombinant inbred line population

Whereas gluten fraction accounts for 30–60% of the variation in wheat bread‐making quality, there remains substantial variation determined by non‐gluten factors. The objective of this study was to detect new loci for wheat quality. The genetics of sodium dodecyl sulphate‐sedimentation volume (Ssd), grain hardness (GH), grain protein content, wet gluten content (WGC) and water absorption (Abs) in a set of 198 recombinant inbred lines derived from two commercial varieties was studied by quantitative trait loci (QTL) analysis. A genetic map based on 255 marker loci, consisting of 250 simple sequence repeat markers and five glutenin loci, Glu‐A1, Glu‐B1, Glu‐D1, Glu‐B3 and Glu‐D3, was constructed. A total of 73 QTLs were detected for all traits. A major QTL for GH was detected on chromosome 1B and its relative contribution to phenotypic variation was 27.7%. A major QTL for Abs on chromosome 5D explained more than 30% of the phenotypic variation. Variations in Ssd were explained by four kinds of genes. Some QTLs for correlated traits mapped to the same regions forming QTL clusters or indicated pleiotropic effects.     

Agronomic and quality characteristics of old,modern and mixture wheat varieties and landraces for organic bread chain in diverse environments of northern Italy

Wheat landraces and old varieties could have an important role for food security not only as source of gene readily available for breeders, but also because they perform well in marginal environments and are more resilient as compared to the modern cultivars. The Italian cereal sector suffers from lack of seed companies that breed specifically adapted varieties for organic and biodynamic farms. Participatory and evolutionary plant breeding (PPB and EPB) have been used in this research to (i) evaluate the agronomic characteristics of old, modern and mixture of varieties and landrace of bread wheat (Triticum aestivum spp.) and their adaptability to organic farming in hilly and mountainous areas; (ii) assess the technological, nutritional and functional properties of grains (rheological characteristic, macro and micro elements contents and antioxidants); (iii) explore the consumers’ preferences for breads obtained by old and modern varieties. Between five and seven old (Sieve, Verna, Gentil Rosso, Andriolo, Gambo di ferro, Frassineto and Abbondanza), two mixtures and four modern (Bolero, Blasco, Arabia and Bologna) varieties were tested for two years in between two and three organic farms (FARM1, FARM2 and FARM3) in hilly areas of Piedmont. Agronomic characteristic were strongly affected by locations and years. On average, Bologna, Abbondanza and Arabia, and the two mixtures were the highest yielding varieties. Flour strength (W) varied greatly ranging from 230 in 2011 for Andriolo to 38 in 2012 for Gambo di ferro. Gluten quality, expressed by GI, was found to be almost within the optimal range but was affected by the year. All six bread samples were acceptable to the 233 consumers who scored them, but the bread produced with old wheat varieties, particularly with Andriolo and Gambo di Ferro, was the preferred one. The old varieties and their mixtures yielded less than the modern varieties but with higher stability as shown by the inability of the modern varieties in FARM1 to survive the winter (they were not harvested) while the old varieties reached maturity showing higher robustness, Therefore, the use of old bread wheat varieties and their mixture, assessed with participatory and evolutionary plant breeding, could represent a strategy for local communities to cope with climate change while improving food security and food quality.     

Heritability estimates of bread wheat quality traits in the Western Cape province of South Africa

High performance liquid chromatography analysis revealed the presence of five phenolic acids in embryos of triticale caryopses (vanillic, caffeic, p-coumaric, ferulic and sinapic). Free phenolic acids reached the highest level at the early stages of development when germination was the lowest and decreased considerably in embryos at the final stage of grain maturation when germination was the highest. Revealing inverse correlation between the contents of free phenolic acids in developing embryos and intensity of precocious germination may indicate a role of phenolic acids in preventing pre-harvest sprouting in cereals. Total content of phenolic acids in embryos (i.e. free, and liberated from soluble esters and glycosides) increased gradually to 43DAF and decreased at full ripeness, whereas the content of total phenolics fluctuated slightly in embryos during development and ripening of caryopses. Enforced dehydration of unripe triticale caryopses stimulated germination both in embryos and whole grains. During the enforced dehydration treatment, a decrease in total content of both phenolic acids and phenolic compounds in embryos of triticale caryopses at different stages of development and maturation was observed. It should be stressed, that a number of naturally occurring phenolics are known to inhibit the germination of cereal grains. A possible role for phenolics in preventing pre-harvest sprouting and acclimation to dehydration in cereals is discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Is it possible to forecast the grain quality and yield of different varieties of winter wheat from Minolta SPAD meter measurements?

To optimize wheat segregation for the various markets, it is necessary to add to genotype segregation, a prediction before harvest of the values of yield and grain protein concentration (GPC) for the different fields of the collecting area. Different tools allowing a prediction of crop production exist. Among them, the evaluation of nitrogen concentration by a chlorophyll meter (Soil–Plant Analysis Development (SPAD) readings), classically used to adapt the nitrogen fertilizer application, has been used in few works to foresee grain yield and grain protein concentration. But the relationships between N crop status and SPAD measurements varies among varieties and this genotypic effect has rarely been incorporated in models of forecasting grain quality.

This paper compares several models to forecast yield, nitrogen uptake in grain (NUG) and grain protein concentration from trials carried out in 2001 and 2002 at the INRA experiment station of Grignon (West of Paris). Trials crossed nine varieties by four (2002) or five (2001) nitrogen rates. Input variables of those models are mainly chlorophyll meter measurements (SPAD) on the penultimate leaf at GS65 and on the flag leaf at GS71 Zadoks growth stages and ear number per square meter (NE).

A square root model of yield based on NE × SPAD gave the best fit (RMSE = 0.6 t ha⁻¹ for both stages) if considering three different groups of genotypes. Based on the same variable, NE × SPAD, a quadratic model for NUG without significant effect of genotypes gave the best fit (RMSE, between 21 and 30 kg ha⁻¹ depending of the growth stage). And, for GPC, considering the same three groups of genotypes, the slope of the linear model with the ratio of predicted grain nitrogen concentration to predicted yield, is the same at both stages and very close to the standard value used to calculate protein concentration from nitrogen concentration (5.7), but the predictive quality of the model is more than 10% higher at GS71 (R² of 0.77) than at flowering (R² of 0.64). Finally, the sensibility of the models to delay in the stage of measurement is discussed.     

Additive and epistatic effects of allelic variation at the high molecular weight glutenin subunit loci in determining the bread-making quality of breeding lines of wheat

Summary The relation has been studied between the high molecular weight glutenin (HMWg) subunit alleles and the bread-making quality of 226 lines of winter wheat (T. aestivum L.), grown in The Netherlands. The lines represented a wide range of genetic backgrounds, and had not been selected for quality, in contrast to the established varieties used by other authors.The variation in HMWg subunit genotypes accounted for about 20% of the total variation in loaf volume among the lines. Most important was the allelic variation at the Glu-D1 locus. The Glu-D1 allele encoding the subunits 5+10 was superior to its allelic counterpart, encoding 2+12. The difference in average of loaf volume between groups of lines containing 5+10 or 2+12 was negatively related with protein content of the flours. When protein content was below 9.2%, no effect of allelic variation at the Glu-D1 locus was present. Epistatic effects between the Glu-I loci also contributed to the variation in loaf volume of the lines: i.e. the effect of allelic variation at Glu-A1 and Glu-B1 depended on the allele present at the Glu-D1. The contribution of the epistatic effects was about half the contribution of the additive effects, and should therefore be included in predictive models for bread-making quality.     

不同基因型小麦籽粒蛋白质合成动态及相关酶活性的研究

以蛋白质含量差异较大的小麦为材料,研究了不同营养水平下籽粒发育过程中蛋白质含量和谷氨酰胺合成酶(GS)、谷氨酸脱氢酶(GDH)活性的动态变化规律及关系,以及小麦生育期功能叶相关酶活性动态变化及与籽粒蛋白质含量的关系。结果表明,两种营养水平下蛋白质含量的动态变化都表现为“高-低-高”的变化趋势,不同品种籽粒的蛋白质积累过程品种间存在差异,PH82-2-2一直处于最高水平,而PH97-4一直处于最低水平,PH97-5在籽粒发育后期蛋白质含量超过济南17,低于PH82-2-2,高于PH97-4。籽粒GS活性在籽粒发育过程中总体呈下降趋势,籽粒蛋白质含量较高的品种,籽粒GS活性较高,反之,较低,PH82-2-2籽粒有较高的酶活性,PH97-4的酶活性较低,籽粒GS活性和蛋白质积累在两种营养水平下在花后21 d,相关显著。对于籽粒GDH活性,PH82-2-2和PH97-5表现趋势基本一致,而济南17和PH97-4表现基本一致,但和籽粒蛋白质积累相关不显著。功能叶片NR活性在开花期最高,高营养水平下起身期和开花期NR活性和籽粒蛋白质含量相关显著;营养水平高叶片GS活性高,品种间表现基本一致;GDH活性品种间表现不完全一致,叶片GS和GDH活性籽粒蛋白质含量相关不显著。     

Changes in the genetic structure of wheat germplasm accessions during seed rejuvenation

Changes in the genetic structure of wheat accessions caused by interspecific competition during periodic seed rejuvenation at a gene-bank were studied. Electrophoretic patterns (Acid-PAGE) of gliadin storage proteins were used to discriminate bread from durum wheat and to identify bread-wheat genotypes. Bread wheat shows high selective advantage over durum wheat and its frequency increased up to 100% after seven rejuvenation cycles. The number of bread-wheat genotypes identified in each entry varied from five to 13, but only a few prevailed and these were different in each accession. In most cases, bread wheat was already present in the field sample collected, but at low frequency. In one case, ‘seed flow’ was thought to have occurred at a very low rate among neighbouring plots. The implication of these findings for genetic resources conservation are: 1. Mixtures of wheat species within the same germplasm accession must be avoided; 2. Only in some cases are low planting densities effective in reducing competition; and 3. The genetic structure of accessions in the gene banks must be monitored.     

A classification of the NORIN 10 and Tom Thumb dwarfing genes in British,Mexican, Indian and other hexaploid bread wheat varieties

Summary The two semi-dwarfing genes Rht1 and Rht2 from Norin 10 have now been incorporated in successful varieties in use in most major wheat growing areas. The more potent dwarfing gene, Rht3, from Tom Thumb has been used in a limited way.These genes may be identified and classified by assessing the associated character of GA-insensitivity in the progeny from test crosses.This paper describes these classifications in the CIMMYT, Mexican, PBI, Cambridge and Indian breeding programmes and for a number of other international varieties.     

山东省主推小麦品种品质性状的近红外光谱分析

摘 要：为给山东小麦品质育种亲本选配提供参考依据,本研究利用近红外光谱技术对山东近两年 25 个主推小麦品种的蛋白质含量、吸水率、面筋含量、形成时间和稳定时间进行检测,结果表明,蛋白质含量和面筋含量达到强筋麦标准的分别占 68% 和 64%,72.00% 小麦品种的形成时间和稳定时间达到中筋麦标准;10% 的小麦品种为强筋麦,90% 的小麦品种为中筋麦,没有检测到弱筋麦。     

江苏省中籼水稻品种演进过程中米质的变化

以江苏省近60年来各阶段具有代表性的13个中熟籼稻品种(含杂交稻组合)为材料,依据品种种植年代结合株型特点将其分为早期高秆(ET)、矮秆(DC)、半矮秆常规稻(SDC)、半矮秆杂交稻(SDH)和超级稻(SR) 5个类型,研究了品种演进过程中米质的变化。结果表明,稻米的碾磨品质(糙米率、精米率和整精米率)在同一类品种间有较大差异,在品种演进过程中无明显变化。与早期品种相比,现代品种(半矮秆杂交稻和超级稻)稻米的垩白度显著降低,崩解值变大,消减值变小,稻米中的清蛋白、谷蛋白、赖氨酸、甘氨酸和精氨酸含量显著增加,醇溶蛋白含量显著降低。随着品种演进,产量逐步提高,其原因主要是总颖花量的增加及每穗粒数的显著增多。说明中籼稻品种演进过程中,米质和产量协同提高。     

氮素营养水平对冬小麦氮代谢关键酶活性变化和籽粒蛋白质含量的影响

通过氮素营养水平对籽粒蛋白质含量差异较大的3个小麦品种的氮素代谢关键酶活性变化及籽粒蛋白质含量影响的研究表明: 增加施氮量能够提高氮素同化关键酶硝酸还原酶和谷氨酰胺合成酶的活性, 降低旗叶蛋白质水解酶的活性. 增加施氮量提高籽粒蛋白质含量主要与促进开花后氮素吸收同化能力有关. 不同品种间籽粒蛋白质含量的差异