Cytogenetical analysis of hybrids between sunflower and four wild relatives

Summary The end-use quality of wheat (Triticum aestivum L.) is determined in large part by the texture of the grain (soft or hard). Endosperm texture is currently determined by several empirical methods. These methods are limited because the use bulk grain lots, as opposed to individual kernels; assess phenotypic, as opposed to genotypic hardness; require a quantity of grain greater than that generally available in the early generations of wheat breeding programs, and are destructive. Recent approaches that use single kernels address the problems associated with bulk grain lots, but suffer the other limitations of providing only the phenotype and being destructive. An objective method for determining the texture genotype of single kernels of wheat was developed using starch granule-associated friabilin, a family of closely related 15 kDa proteins, as a biochemical marker. The occurrence of friabilin on water-washed wheat starch granules is apparently unaffected by the environment and is perfectly correlated (no exceptions) with grain softness. The technique presented here can detect friabilin on as little as 0.2 mg of starch and provides a 250-fold improvement in friabilin detection compared to previous methods. The method is capable of correctly assessing the genotype of F₁ heterozygotes from hard x soft and soft x hard crosses. Further, the method uses only a portion of the endosperm from the kernel and therefore accommodates embryo propagation and high molecular weight glutenin subunit characterization. This single kernel method also facilitates the genetic characterization of mixed, bulk grain lots.Abbreviations HMW high molecular weight - HRS hard red spring - HRW hard red winter - HWS hard white spring - NIR near infrared reflectance - PAGE polyacrylamide gel electrophoresis - PDA piperazine diacrylamide - PSI particle size index - SDS sodium dodecyl sulfate - SKWCS single kernel wheat characterization system - SWS soft white spring - SWW soft white winter - TCA trichloroacetic acid - Tris tris(hydroxymethyl)amino methane     

High Frequencies of Fertilization and Haploid Seedling Production in Crosses Between Commercial Hexaploid Wheat Varieties and Maize

Nineteen commercial hexaploid wheat varieties were crossed with the maize F₁ hybrid ‘Seneca 60’. Fertilization frequencies ranged from 32.1 % to 47.5 % of pollinated florets (mean 39.5 %) in the 14 winter wheat varieties and from 40.7 % to 51.4 % (mean 47.8 %) in the five spring wheat varieties. In some cases only an endosperm was formed and the frequencies of embryo formation were therefore slightly lower, being 28.2 % to 45.9 % (mean 36.4 %) for winter wheats and 39.8 % to 48.6 % (mean 45.1 %) for spring wheats. Mean values were significantly higher in the spring wheats but no significant variation was found between varieties within the spring or winter categories. In the five spring wheats the mean yield of embryos, and hence the potential yield of haploid plants, was 3.4-fold higher than with the tetraploid Hordeum bulbosum clone PB179. For the 14 winter wheats the figure was 10.9-fold higher. These differences were highly significant (p < 0.001) in all varieties. A single 2,4-D treatment given to spikes one day after pollination with maize enabled embryos to be recovered from all 19 varieties. A total of 311 embryos were recovered from 950 florets (an average of 7.3 embryos per spike) of which 191 germinated, giving an average yield of one haploid plant for every 5.0 florets pollinated (4.4 haploid plants per spike).     

小麦品质的麦谷蛋白亚基评定标准研究

测定了233份小麦面粉样品的高分子量谷蛋白亚基(HMW-GS)含量、Zeleny-沉降值和谷蛋白大聚体(GMP)含量,并根据SDS-PAGE结果计算了其Payne亚基品质评分.结果表明,不同HMW-GS含量差异显著,不同HMW-GS所对应品种的HMW谷蛋白总量、沉降值、GMP含量、Payne品质评分平均值也存在显著差异,说明不同亚基对品质的影响存在显著差异.HMW谷     

High molecular weight glutenin subunit composition of Chinese bread wheats

Summary The endosperm storage proteins of 205 Chinese bread wheat cultivars and advanced lines were fractionated by SDS-PAGE to determine their high molecular weight (HMW) glutenin subunit composition. Seventeen alleles were identified: three at Glu-A1, eight at Glu-B1, and six at Glu-D1. The most common alleles were Null, 1, 7+8, 7+9, and 2+12. The results indicate that wheats from different regions differ in their frequencies of HMW glutenin subunits, however, none of the subunits could be related to specific environments. The glutenin quality scores of Chinese wheats ranged from 3 to 10, with an average of 6.7. Increasing quality scores have implications in improving steam-bread making quality for Chinese consumers. On the basis of HMW glutenin subunit composition, Chinese wheats are close to European wheats, especially Italian wheats because several Italian introductions are widely distributed in the pedigrees of Chinese wheat.     

Variation at Glu-1 Loci in Club Wheats

Hexaploid club wheats (Triticum aestivum L.) possess unique end-use quality characteristics and are grouped as a U.S. market subclass of soft white common wheat. Although there have been many reports on associations among high-molecular-weight glutenin storage protein (HMW-Glu) sub-units with end-use quality in hard wheats; there has been very limited work done on surveying the club wheats for these subunits. The HMW-Glu subunits, spike types and grain color were determined for 41 U.S. club wheat cultivars and 79 club accessions obtained from the National Small Grains Collection (NSGC), USDA-ARS. Accession ‘Harlan JR 35’ (PI 420948), which appears morphologically to be a hexaploid club wheat, was determined to be tetraploid. Egyptian line ‘Maya II-Tel's’ (PI 422288) was shown to have previously undescribed HMW-Glu subunits. In the U.S. club wheats the most common HMW-Glu subunits were: null, 49 % (Glu-A1); 6, 37 % (Glu-B1); and 2 + 12, 94 % (Glu-D1). In the NSGC group the most common HMW-Glu sub-units were: 2*, 52 % (Glu-A1); 7 + 8, 31 % (Glu-B1); and 2 + 12, 92 % (Glu-D1). The high frequency of subunits 2 + 12 in the club wheat groups has not been observed previously in numerous surveys of diverse wheat cultivars. The Glu-B1 subunits 6 (without subunit 8) and 20 which have not been reported in US red wheats, were shown to be common in both club wheat groups. A comparison of diversity indices, including previous studies on HMW-Glu subunit frequencies on all market classes of wheat, showed that the club groups are as diverse for the Glu-A1 and Glu-B1 loci and less diverse for the Glu-D1 locus.     

General combining ability of six genotypes of spring wheat (Triticum aestivum) for biscuit-making quality characteristics

The first South African soft wheat breeding programme was initiated in 19 90 , consequently almost no information is available on soft wheat quality characteristics. The aim of this study was to determine general combining ability (GCA) of several spring wheats for biscuit-making quality characteristics. A full dialled cross was made with five spring wheats with good biscuit-making quality and a sixth hard wheat with poor biscuit-making quality. Seventeen quality characteristics were measured. When the GCA to specific combining ability (SCA) ratios were calculated, strong additive gene action was shown for all characteristics, excluding flour colour and biscuit diameter, which suggested high heritabilities for most characteristics. None of the characteristics showed more non-additive than additive gene action. Three of the soft wheat cultivars combined well for the characteristics important for biscuit-making quality.     

冬小麦品种的HMW-GS组成和1BL/1RS易位分布及其与品质性状的关系研究

研究了我国代表性冬小麦品种(系)高分子量麦谷蛋白亚基(HMW-GS)以及1BL/1RS易位的分布和组成,探讨了其对揉面仪特性等小麦加工品质性状的影响,结果表明:在Glu-A1位点,我国小麦品种中1亚基的频率为64.0%,N亚基为32.5%,2*亚基频率低,为3.5%;在Glu-B1位点,7 9亚基占56.8%,7 8亚基为26.4%,14 15亚基为10.7%,而20,13 16,7亚基的材料极少(频率分别为3.6%,1.5%和1%);在Glu-D1位点,2 12和4 12亚基合计占63.0%,而5 10亚基的比例偏低,为37.0%.1BL/1RS易位系的比例仍然偏高,为50.8%.HMW-GS组成及1BL/1RS易位对小麦加工品质影响较大,其中5 10亚基对小麦绝大多数加工品质指标起正向作用,而1BL/1RS易位对大多数品质指标起负向作用.因此,我国小麦品种5 10亚基的频率仍然偏低,1BL/1RS易位系频率仍然偏高,可能正是目前我国小麦生产中优质品种面筋强度不够,品质稳定性差的原因所在.根据SDS-PAGE麦谷蛋白电泳结果或分子标记进行优质高、低分子量麦谷蛋白亚基选择,提高5 10等优质亚基的比例,并根据醇溶蛋白电泳结果进行1BL/1RS易位筛选,降低1BL/1RS频率,应成为今后我国优质小麦育种的重要目标和手段之一.     

Influence of winter and spring wheat genetic backgrounds on haploid induction parameters and trait correlations in the wheat × maize system

The interactive influence of winter and/or spring wheat genetic background on haploid induction parameters and trait correlation was studied by hybridizing five elite and diverse genotypes each of winter and spring wheat and their F₁s (winter × winter, spring × spring, and winter × spring, generated in a diallel design excluding reciprocals) with a single genotype of maize. Data were recorded with respect to per cent seed formation, embryo formation, and regeneration. High genetic variability was present among the wheat genotypes (parents + F₁s) for the three haploid induction parameters. Significant differences were obtained within and between different groups viz., spring wheats, winter wheats, spring × spring wheats, winter × winter wheats, and winter × spring wheats with respect to the three haploid induction parameters based on ANOVA. The winter genotypes (winter parents and winter × winter wheat hybrids) responded better than the spring groups (spring wheat parents, spring × spring and winter × spring wheat hybrids) with respect to embryo formation and winter × spring wheat hybrids yielded significantly the highest numbers of regenerants. Correlation studies amongst the haploid induction parameters indicated that the genes controlling seed formation and haploid plantlet regeneration are negatively correlated when the genetic backgrounds of both ecotypes are combined in winter × spring hybrids. Haploid embryo formation had no association with seed formation and regeneration in all genetic backgrounds, suggesting independent inheritance.     

The HMW glutenin suhunit composition of bread-wheat varieties bred in Pakistan

A total of 50 bread-wheat varieties bred in Pakistan were characterized for the composition of the high-molecular-weight glutenin subunit (HMW-GS). The glutenin subunits, as revealed by sodium dodecyl-sulfate-polyacrylamide-gel electrophoresis (SDS-PAGE) were numbered according to Payne's numbering system and, varieties were accordingly assigned theoretical quality scores. All varieties were found to possess either subunit 1 or 2* coded by the A genome. Subunits 17+18 and 7 + 9 of the B genome and 5+10 of the D genome were predominantly found in this set of varieties. The frequency of the appearance of Glu-l alleles in the varieties was different from that seen in other countries, especially in terms of the absence of the ‘null’ form of the A genome and the presence of novel subunits at the Glu-Bl and Glu-Dl loci. The compositions of HMW-GS were generally of good quality, with more than 50% of the varieties achieving quality scores of 9–10 with a high (8.6) average score. The results in this study indicate that wheat varieties bred in Pakistan have a narrow genetic base in terms of HMW glutenin subunits. It appears that the breeders have been selecting wheat genotypes of glutenin subunits associated with good quality without knowing the actual composition of these subunits. The database established on the basis of these results is useful for wheat-improvement programmes aimed at varietal identification and breeding for good quality parameters.     

Allelic variation in high-molecular-weight glutenin subunit Loci of Glu-1 in Japanese common wheats

Seed storage proteins of 131 Japanese Norin wheat (Triticum aestivum) varieties were fractionated by sodium dodecyl sulfate polyacrylamide gel electrophoresis to determine allelic make-up in varieties at each of three loci that control high-molecular-weight (HMW) glutenin subunits. Three alleles were identified at the Glu-A1 locus, six at the Glu-B1 locus and five at the Glu-D1 locus. Twenty-four different, major glutenin HMW subunits were identified and each contained three to five subunits and seventeen different glutenin subunit patterns were observed for 19 subunits in the 131 Japanese Norin varieties. Fourteen alleles were identified by comparison of subunit mobility with that previously found in hexaploid wheat. Japanese Norin varieties showed a specific pattern of allelic variation in glutenin HMW subunits, different from that of Chinese and other country common wheats in allelic frequency at Glu-1 loci. This revised version was published online in July 2006 with corrections to the Cover Date.     

Allelic variation at high-molecular-weight glutenin subunit Loci, Glu-A1, Glu-B1 and Glu-D1, in Japanese and Chinese hexaploid wheats

Variation in the electrophoretic banding patterns of high-molecular-weight (HMW) glutenin subunits of 274hexaploid wheat (Triticum aestivum) varieties from China was examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and 27 different major HMW glutenin subunits were identified. Each variety contained three to five subunits and 29different glutenin subunit patterns were observed in274 Chinese hexaploid wheats. Seventeen alleles were identified based on the comparison of subunits mobility with that previously identified in a set of standard hexaploid wheats. The Chinese hexaploid wheats exhibited allelic variation in HMW glutenin subunit composition and the variation differed from that of Japanese and hexaploid wheats of other countries. This revised version was published online in July 2006 with corrections to the Cover Date.     

Wheat breeding for end-product use

High grain yield is the primary objective of most wheat breeding programs around the world. In some countries, for example Australia and Canada, a new wheat cultivar must meet a prescribed level of quality before it can be registered for commercial production. For most traditional uses, wheat quality derives mainly from two interrelated characteristics: grain hardness and protein content. Grain hardness is a heritable trait but it can be strongly affected by abnormal weather conditions such as excessive rainfall during the harvest period. Protein content is weakly heritable and strongly dependent on environmental factors such as available soil nitrogen and moisture during the growing season. In addition, each end-use requires a specific 'quality' in the protein. Quality is determined by the molecular structure of the major proteins of flour which, in turn, controls the interactions of the proteins during the breadmaking process. Durum wheats have the hardest grain texture and are usually high in protein content. They are especially suited to the production of pasta because of their highly vitreous grain (high milling yield of semolina), unique combination of storage proteins for good cooking quality of pasta, and high yellow pigment content required for attractive appearance of cooked product. All three characteristics are highly heritable and can be readily improved by conventional breeding. Recent research has shown that the presence of γ-gliadin 45 is a reliable marker of good cooking quality. This marker is now used for screening early generation material in many durum wheat breeding programs. Common (hexaploid) wheats cover a wide range of grain hardness and protein content. The hardest wheats of this class, generally highest in protein, are used for pan bread. Considerable progress has been achieved in research of the molecular properties of flour proteins that are required for highest bread quality. The key protein component in this regard is glutenin. Segregating breeding populations can be screened by electrophoresis or high performance liquid chromatography for the presence of desirable glutenin subunits. Common wheats of medium hardness and lower protein content are used for other types of bread and noodles. Wheats with softest texture and lowest protein are used for cakes and cookies. In some end-uses, e.g., Chinese-type noodles, starch quality is important together with protein quality; this feature should be taken into consideration in developing a screening strategy for wheats for this application. Screening tests that reflect end-use requirements for most of the known products are available, and should be applied in testing wheats according to intended use. This revised version was published online in August 2006 with corrections to the Cover Date.     

小麦剩余蛋白含量与面包烘烤品质

测定了21个小麦品种(系)的麦谷蛋白、酸可溶性麦谷蛋白和剩余蛋白的含量以及流变学特性指标,作了沉淀试验和面包烘烤试验,进行了逐步回归分析、通径分析和系统聚类分析。结果表明:剩余蛋白含量作为预测面包烘烤品质的量要指标是可靠的,在小麦品质育种中以剩余蛋白含量对育种材料进行选择是可行的。     

Effect of variation at Glu-D1 on club wheat end-use quality

Club wheats (Triticum aestivum L.), having the allele at the C locus conferring short spike rachis internodes and giving compact appearance of spikes, which have unique and highly desirable soft white wheat end-use quality characteristics are a vital submarket class of soft white wheat in the US Pacific Northwest. Two important varieties, ‘Tyee’ and ‘Albit’, are heterogeneous for high molecular weight glutenin subunits 2 + 12 and 5 + 10 encoded by the Glu-D1 locus. Replicated near-isogenic lines (NILs) of club wheats ‘Tyee’ and ‘Albit’ were grown in four field environments and used to determine the effect of Glu-D1 coded high molecular weight glutenin subunits (HMWGS) 5 + 10 and 2 + 12 on various end-use quality traits. The greatest effect of variation at this locus was observed for mixing time to peak, where there was significant variation (P < 0.01) between each 5 + 10 and 2 + 12 NIL group in each environment. Mixing time values for the 2 + 12 NILs for both ‘Albit’ and ‘Tyee’ ranged from 0.60 to 1.23 min lower than the 5 + 10 NILs. Mean values for traits mixing time to peak, cake volume, and viscosity were more favourable for the 2 + 12 NIL groups for all genotypes in all environments. No effects of these HMWGS were detected for test weight, kernel hardness, whole wheat protein, flour yield, ash, flour protein or cookie diameter. Selection for HMWGS 2 + 12 in club wheat breeding programmes should have positive effects on end-use quality.     

Breeding for breadmaking quality using old Hungarian wheat varieties

Due to their broad population diversity, old wheat varieties or landraces play an important role in increasing the genetic variability of agronomic traits. On these grounds, an analysis was made of the high molecular weight (HMW) glutenin subunit composition of the old Hungarian wheat variety Bánkúti 1201. It was found that several genotypes with differing breadmaking qualities can be distinguished for this character. When using old varieties in breeding, it is possible to broaden the genetic background of characters responsible for breadmaking quality by separating the populations. A more detailed analysis of the protein composition of germplasm created in this way will be required to obtain a better understanding of this complex character for its conscious introduction into breeding programmes. This revised version was published online in August 2006 with corrections to the Cover Date.     

甘肃春小麦资源HMW-GS组成研究

应用十二烷基磺酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)方法,分析了176份甘肃省春小麦资源的高分子量麦谷蛋白亚基(HMW-GS)组成.结果表明,甘肃省春小麦资源的亚基组成较丰富,共检测到18种亚基变异类型和28种亚基组合类型.地方品种的亚基组合类型较少而且以Null、7+8、2+12为主,育成品种的亚基变异类型比地方品种丰富,以1、7+8、2+12 3种变异类型的出现频率为最高.供试材料HMW.GS的品质评分在4～10分之间,平均得分7.2,所筛选出的一批含优质亚基组合的材料可供育种工作者利用.     

Winter × spring wheat hybridization - a promising avenue for yield enhancement

Introgression of the winter gene pool into spring wheat is being considered as one of the strategies to break through the yield plateau. However, little information is available on the combining ability of these two important but distinct groups of wheats in Indian conditions. Therefore, the present study was undertaken to determine the combining ability and gene action of yield and yield attributes in winter × spring wheat crosses. Seventy F₁ progenies developed by 14 winter and five spring wheat lines using a line × tester design were evaluated, along with their parents, for yield and yield attributes in a randomized complete block design under field conditions. The mean squares for all the characters studied showed highly significant differences. The mean squares due to female × male interactions were significant for all the characters studied except for grains per ear and grain weight per ear. Additive genetic effects were found to play a key role in controlling the expression of days to heading, plant height and spikelets per ear.‘MV 19’ and ‘Stepniak’/‘Karvuna’ among winter and ‘PBW 65’ among spring wheats were good general combiners for most of the yield attributes studied. The estimates for specific combining ability effects suggested that, although general combining ability (GCA) effects of most winter wheats are either average or poor, their combination can give desirable genotypes with spring wheat parents possessing a high GCA.     

Reciprocal performance of winter wheat in Hungary and Oklahoma, USA

International wheat ( Triticum aestivum L.) performance trials have revealed adaptive responses in vernalization and photoperiod for certain Eastern European cultivars when field-tested in Oklahoma in south central USA. Common experiments were conducted in Hungary and Oklahoma with 12 elite germplasm varieties or lines from each locale to uniformly and directly compare the agronomic potential of hard red winter (HRW) North American wheat and Hungarian bread wheat and to identify potential benefits or hazards for introducing germplasm into reciprocal breeding programmes. Results from four Oklahoma and six Hungarian environments showed that non-native cultivars were 14% and 25% lower in grain yield than native ones in Hungary and Oklahoma, respectively, although one HRW cultivar (2163) exhibited exceptional yield potential in both locations. The lower grain yield potential of Hungarian genotypes in Oklahoma was reflected primarily in lower spike production at harvest. Yield performance in one location did not correlate with performance in the other. Greater consistency between locales was found for test weight (r = 0.6, P < 0.05) and heading date (r = 0.9, P < 0.01); thus, screening for those traits prior to introduction of parent material may be useful. Although some recovery of the genetic yield potential of native material will be necessary, intergroup crossing between these apparently distinct gene pools should provide a new and valuable resource for bread wheat cultivar development.     

Iron and zinc grain density in common wheat grown in Central Asia

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. Within spring wheat, a strongly significant positive correlation was found between Fe and Zn. Grain protein content was also significantly (P < 0.001) correlated with grain Zn and Fe content. There were strong significantly negative correlations between Fe and plant height, and Fe and glutenin content. Similar correlation coefficients were found for Zn. In winter wheat, significant positive correlations were found between Fe and Zn, and between Zn and sulfur (S). Manganese (Mn) and phosphorus (P) were negatively correlated with both Fe and Zn. The additive main effects and multiplicative interactions (AMMI) analysis of genotype × environment interactions for grain Fe and Zn concentrations showed that genotype effects largely controlled Fe concentration, whereas Zn concentration was almost totally dependent on location effects. Spring wheat genotypes Lutescens 574, and Eritrospermum 78; and winter wheat genotypes Navruz, NA160/HEINEVII/BUC/3/F59.71//GHK, Tacika, DUCULA//VEE/MYNA, and JUP/4/CLLF/3/II14.53/ODIN//CI13431/WA00477, are promising materials for increasing Fe and Zn concentrations in the grain, as well as enhancing the concentration of promoters of Zn bioavailability, such as S-containing amino acids.     

Genetic variation for resistance to Fusarium head blight in bread wheat

Summary During a four year period, a total of 258 winter and spring wheat genotypes were evaluated for resistance to head blight after inoculation with Fusarium culmorum strain IPO 39-01. It was concluded that genetic variation for resistance is very large. Spring wheat genotypes which had been reported to be resistant to head blight caused by Fusarium graminearum were also resistant to F. culmorum. The resistant germplasm was divided into three gene pools: winter wheats from Eastern Europe, spring wheats from China/Japan and spring wheats from Brazil. In 32 winter wheat genotypes in 1987, and 54 winter wheat genotypes in 1989, the percentage yield reduction depended on the square root of percentage head blight with an average regression coefficient of 6.6. Heritability estimates indicated that for selection for Fusarium head blight resistance, visually assessed head blight was a better selection criterion than yield reduction.