Genetic characterization of kernel polyphenol oxidases in wheat and related species

Polyphenol oxidase (PPO) activity causes undesirable darkening of raw Asian noodles and other wheat products. In this study we investigate the genetic origins and diversity of wheat kernel PPO. PPO was characterized via activity assays, antigenic staining, and Southern blots in Triticum aestivum, Triticum dicoccoides, Triticum durum, Triticum dicoccum, Triticum monococcum, Triticum urartu, Aegilops speltoides, and Aegilops tauschii. Among these species, PPO activity was well-correlated with antigenic staining intensity toward a wheat kernel-type PPO antibody. High PPO activity was observed in all three T. monococcum accessions (A^m genome), one Ae. speltoides accession, one T. durum accession, and two hexaploid wheat cultivars. Southern blots suggested the presence of two or more kernel-type PPO genes in diploid progenitors of the hexaploid A, B, and D genomes. Whole-kernel PPO activity was evaluated in disomic substitution lines derived from three T. dicoccoides accessions in the background of T. durum ‘Langdon’. PPO activity was primarily associated with chromosome 2A and to a much lower degree with chromosome 2B. DNA sequence comparisons showed that the intron associated with the high PPO allele on chromosome 2AL of hexaploid wheat had 94% nucleotide identity with the homeologous intron found in T. monococcum, a species with high kernel PPO activity. This implies that the ancestral PPO allele on the A genome is one of the high activity, and the low PPO allele found in hexaploid wheat represents a relatively recent genetic alteration. Results confirm the presence of multiple kernel-type PPO genes in the diploid and tetraploid progenitors and relatives of hexaploid wheat. However, it is likely that relatively few of the many kernel-type PPO genes present in wheat contribute substantially to kernel PPO activity. A single genetic locus on homeologous group 2 chromosomes may be the primary cause of high PPO activity in wheat kernels.     

Molecular and Biochemical Characterisation of HMW Glutenin Subunits fromT. tauschiiand the D Genome of Hexaploid Wheat

Electrophoretic (urea SDS–PAGE) and chromatographic (RP–HPLC) analysis was performed on 8 allelic variants of HMW glutenin subunits derived fromTriticum tauschiiand from the D genome of a hexaploid wheat species (Triticum macha) and hexaploid landraces. These subunits had been previously identified using SDS–PAGE. The characterisation revealed that subunits Dy10^tand Dy12^tfromT. tauschiicould be differentiated from their bread wheat counterparts using both urea SDS–PAGE and RP–HPLC. In the latter case, theT. tauschiiy-type subunits were clearly more hydrophobic than the Dy type subunits of bread wheat. The characterisation also suggested that subunit Dx5^t, derived from two separateT. tauschiiaccessions, did not contain the extra cysteine residue characteristic of Dx5 from bread wheat. RFLP analysis of the genes encoding the HMW glutenin subunits of interest suggested that the absence of Dx-type HMW glutenins in two hexaploid landraces was due to lack of expression of their encoding genes. The relationship betweenHindIII DNA fragment size and protein subunit size, as measured by electrophoretic mobility, is examined and discussed. Finally, the solubility properties of a HMW protein designated T1 (derived fromT. tauschiiaccession AUS 18913) suggested that it was not a HMW glutenin subunit as was previously thought. Further studies are needed to clarify the identity of this subunit.     

Molecular mapping of the hybrid necrosis gene NetJingY176 in Aegilops tauschii using microsatellite markers

The rich genetic variation preserved in collections of Aegilops tauschii can be readily exploited to improve common wheat using synthetic hexaploid wheat lines. However,hybrid necrosis, which is characterized by progressive death of leaves or plants, has been observed in certain interspecific crosses between tetraploid wheat and Ae. tauschii. The aim of this study was to construct a fine genetic map of a gene(temporarily named Net Jing Y176)conferring hybrid necrosis in Ae. tauschii accession Jing Y176. A triploid F1 population derived from distant hybridization between Ae. tauschii and tetraploid wheat was used to map the gene with microsatellite markers. The newly developed markers Xsdau K539 and Xsdau K561 co-segregated with Net Jing Y176 on chromosome arm 2DS. The tightly linked markers developed in this study were used to genotype 91 Ae. tauschii accessions. The marker genotype analysis suggested that 49.45% of the Ae. tauschii accessions carry Net Jing Y176. Interestingly, hybrid necrosis genotypes tended to appear more commonly in Ae. tauschii ssp. tauschii than in Ae. tauschii ssp. strangulata.     

人工合成小麦染色体区段在小麦优良新品系中的分布

从人工合成六倍体小麦SHW-L1改良后代中选育的5个春小麦新品系,在青海表现出比对照品种高原448更优的农艺性状和产量潜力,推测源于外源物种的野生不良性状被淘汰,保留在新品系中的外源染色体区段可能对遗传改良有贡献。为了了解源自人工合成小麦SHW-L1的外源染色体区段在这5个改良新品系中的分布,利用11 660个具有染色体位置信息的多态性DArTseq标记对这5个改良品系进行了外源染色体区段分析。结果表明,共检测到78个外源染色体区段,其中,65个为源于四倍体小麦的A和B基因组,13个为来自于节节麦的D基因组。24个源于四倍体小麦的外源染色体区段分布于3个以上的品系中,这些区段主要来自于A基因组,其中2A有8个,7A有4个,1A有3个,6A有3个。本研究材料来自于混合选择,不同品系共有的外源染色体区段可能含有对当前育种有价值的重要基因位点或基因簇,这样的区段将是下一步关注的重点。     

Puroindoline grain hardness alleles in CIMMYT bread wheat germplasm

Grain hardness is an important quality parameter of bread wheat (Triticum aestivum L.) with importance for wheat classification and end use properties, and is controlled by the genes puroindoline a (Pina) and puroindoline b (Pinb). The presence of known hardness alleles was studied in a representative sample of 373 bread wheat lines from the breeding program at CIMMYT. The PINA-null mutation (Pina-D1b) was the most frequent hardness allele and present in 283 of the 328 lines with hard endosperm. All other hard wheat had the glycine to serine mutation in PINB (Pinb-D1b). A study of historically important CIMMYT bread wheat lines showed that Pina-D1b has been the dominating hardness allele since the inception of the wheat breeding program in Mexico. New puroindoline alleles have recently been introduced through the extensive use of synthetic hexaploid wheat, and the textural effects of various Aegilops tauschii-derived Pina and Pinb alleles were studied in 92 breeding lines derived from various crosses with synthetic wheat. Progeny lines with Pina-D1j/Pinb-D1i were on average 10 SKCS hardness units softer than those carrying the allelic combination Pina-D1c/Pinb-D1h. Further investigation is needed to validate the potential of such minor allelic differences for the improvement of soft wheat quality.     

Identification of SNPs and development of allelic specific PCR markers for high molecular weight glutenin subunit Dtx1.5 from Aegilops tauschii through sequence characterization

The high molecular weight (HMW) glutenin subunits D^tx1.5+D^ty10 from Aegilops tauschii are a novel pair of subunits not detected previously in common wheat (Triticum aestivum). The partial DNA sequences of the x-type HMW glutenin alleles from A. tauschii and synthetic hexaploid wheat samples with different HMW glutenin subunits were charcterised. Five samples were found to contain the HMW glutenin subunit D^tx1.5 that may affect bread-making quality. Polymorphisms of the DNA sequences were detected among alleles encoding different HMW glutenin subunits and within an allele encoding the same HMW glutenin subunit, such as the D^tx1.5 subunit. Three single nucleotide polymorphisms (SNPs) that can distinguish the Dx^t1.5 from D^tx2, D^tx5, Dx2 and Dx5 alleles were identified. Allelic specific (AS)-PCR primers were developed based the SNPs located at the non-repetitive N-terminal of the HMW glutenin subunits. The AS-PCR primers can accurately identify accessions containing the D^tx1.5 subunit from those containing other studied subunits by PCR analysis, suggesting the usefulness of AS-PCR for identifying different HMW glutenin subunits of A. tauschii and synthetic hexaploid wheat. The AS-PCR primers developed based on SNPs in this study are valuable in wheat breeding for effective selection of special HMW glutenin subunits.     

节节麦pbf基因的克隆、序列分析及原核表达

醇溶蛋白盒结合因子(prolamin-box binding factor,PBF)通过调控籽粒蛋白的表达效率进而影响面粉的加工品质。为给深入研究小麦籽粒PBF对籽粒蛋白质表达调控的分子基础提供参考依据,进而为小麦面粉加工品质的改良提供候选基因资源,利用特异引物组合pbfF1/pbf R1分别从两份节节麦(AS90、AS2386)中克隆出pbf基因后进行序列分析,并进一步构建pbf基因的原核表达体系。结果表明,从两份节节麦中克隆得到了2个不同类型的pbf基因(GenBank登录号分别为KJ544771和KJ544772),其中来源于AS2386的KJ544772与来源于普通六倍体小麦的1个pbf基因序列完全相同。推导的氨基酸序列分析表明,KJ544771和KJ544772所编码的蛋白质均为弱碱性的亲水蛋白,具有典型的DOF蛋白结构域。与其他远缘物种来源的PBF比对结果表明,该类蛋白在NLS核心、DOF结构域及Ser铰链区相对保守,而在C-端调控区变异较大,说明PBF蛋白具有种属特异性。同时,系统演化树显示,来源于节节麦AS2386的pbf基因与迄今已知的全部普通小麦的pbf基因具有高度的相似性,因此推测该种类型的节节麦很可能参与了最初的普通六倍体小麦的形成。此外,本研究成功构建了pbf基因的原核表达体系,可为后续功能验证的开展奠定基础。     

Evaluation and characterization of high-molecular weight 1D glutenin subunits from Aegilops tauschii in synthetic hexaploid wheats

The high-molecular weight (HMW) glutenin subunits of bread wheat are major determinants of end-use quality. The objective of this study was to determine the 1Dx and 1Dy subunits present in 43 synthetic hexaploid wheat (SHW) lines derived by crossing durum ‘Langdon’ to 43 Aegilops tauschii accessions. Protein samples were initially electrophoresed multiple times on SDS-PAGE gels to arrange subunits into similar groups and then were electrophoresed on urea/SDS-PAGE gels. Initial results with SDS-PAGE gels indicated that there were six 1Dx and six 1Dy subunits in these SHW lines. However, results of the urea/SDS-PAGE indicated that some of the subunit groups could be further differentiated into additional subunits. A total of eleven 1Dx and eight 1Dy subunits including the newly designated subunits 1Dx2^t-1, 1Dx2^t-2, 1Dx2^t-3, 1Dx1.5^t-1, 1Dx2.1^t-1, 1Dy10^t-1, and 1Dy12^t-1 were identified, and they composed 17 1Dx and 1Dy combinations in the SHW lines. Eight of the combinations included at least one novel subunit and hence they were novel Glu-D1 alleles. Our results indicated that urea/SDS-PAGE can be very useful in identifying new HMW glutenin subunits. Quality testing of the SHW lines will determine if any of the alleles are useful in improving wheat-baking quality.     

节节麦幼胚再生体系的建立

为建立高效的节节麦幼胚再生体系,以节节麦幼胚为外植体,通过正交设计,探索基本培养基、2,4-D、碳源、KT等因素对幼胚愈伤组织诱导、分化及植株再生效果的影响。结果表明,4种因素中,基本培养基对节节麦幼胚愈伤组织诱导的影响最显著(P0.05),2,4-D浓度对节节麦幼胚愈伤组织诱导也有显著影响(P0.05),添加3.0mg·L~(-1) 2,4-D的培养基诱导出的愈伤组织质量高,淡黄色,表面呈不规则颗粒状,质地致密,再生频率可以达到17.62%。KT浓度对节节麦愈伤分化影响最显著,基本培养基、2,4-D和碳源对节节麦幼胚愈伤分化均无显著影响。不同碳源对节节麦幼胚愈伤组织诱导和分化的影响均不显著,为节约成本可直接选用30g·L~(-1)蔗糖作为碳源。节节麦幼胚组织培养的最佳组合是:愈伤诱导培养基为MS培养基+3mg·L~(-1) 2,4-D+15g·L~(-1)蔗糖+15g·L~(-1)甘露醇,愈伤分化培养基为MS培养基+15g·L~(-1)蔗糖+15g·L~(~(-1))甘露醇+1.0mg·L~(-1) KT。     

Reconciliation of D-genome puroindoline allele designations with current DNA sequence data

Kernel texture is an important trait in cereals, especially wheat (Triticum spp.). Throughout the Triticeae, the puroindoline genes act to soften kernel endosperm. Absence or mutation of either or both of the two puroindolines, ‘a’ and ‘b’, in Triticum aestivum results in harder grain texture. Apparently only one puroindoline haplotype was contributed by the Aegilops tauschii variety that contributed the D-genome during allopolyploidization. Yet, world collections of Ae. tauschii exhibit a range of puroindoline sequence polymorphisms. Consequently, these genes, through synthetic hexaploids (× Aegilotriticum) can enrich the wheat gene pool. Lastly, the puroindolines represent a useful tool for phylogenetic analyses. Here we review original sequence data published and/or available in public databases to reconcile the known gene sequence polymorphisms with a systematic approach to the designating of puroindoline gene and allele symbols in T. aestivum, Ae. tauschii, and × Aegilotriticum. This system follows the recommendations adopted by the International Wheat Genetics Symposium and described in the Catalogue of Gene Symbols for Wheat. Errors, discrepancies and ambiguities in the puroindolines are reviewed; a reconciliation of all existing data is outlined.     

Puroindolines co-localize to the starch granule surface and increase seed bound polar lipid content

Endosperm texture in wheat is controlled by the Pina and Pinb genes that comprise the Hardness (Ha) locus. Studies have shown that soft and hard varieties differ in the amount of starch bound polar lipids but have not addressed whether PINs are directly involved and whether the presence of one particular PIN affects seed polar lipid levels and cellular localization. Here, we determined the effect of overexpressing PINA or PINB on seed bound polar lipids and PIN localization. F₃ recombinants homozygous for either a Pina or Pinb null Ha locus with or lacking a transgenically added Pina or Pinb were analyzed for grain hardness, PIN abundance, and seed bound polar lipid levels. Overexpressed PINs resulted in reduced hardness, increased starch bound PINs, and increased seed bound polar lipids. Addition of PINA to the PINA nulls or PINB to the PINB nulls resulted in higher bound polar lipid levels than the addition of the alternative PIN. Both PINs localized to the starch surface in the presence or absence of the other protein. Our results indicate that PIN overexpression results in reduced endosperm texture and increased seed bound polar lipids and that PINs independently localize to the surface of starch granules.     

Development and Molecular Characterization of Wheat-Aegilops peregrina Introgression Lines with Resistance to Leaf Rust and Stripe Rust

A wild non-progenitor species from wheat (Triticum aestivum L.) tertiary gene pool, Aegilops peregrina (Hack.) Maire & Weiller accession pau3519 (UUSS), was used for introgression of leaf rust (caused by Puccinia triticina) and stripe rust (caused by Puccinia striiformis f. sp. tritici) resistance in bread wheat. The accession was crossed and backcrossed with hexaploid wheat line Chinese Spring Ph^I to develop two homozygous BC₂F₆ wheat-Ae. peregrina introgression lines (ILs), viz., IL pau16058 and IL pau16061, through induced homoeologous recombination. Homozygous lines were screened against six Puccinia triticina and two Puccinia striiformis f. sp. tritici pathotypes at the seedling stage and a mixture of prevalent pathotypes of both species at the adult plant stage. IL pau16061 showed resistance to leaf rust only, whereas IL pau16058 was resistant to both leaf and stripe rust pathotypes throughout plant life. Molecular profiling of these ILs with simple sequence repeat (SSR) markers indicated that alien introgressions were mainly terminal and very few were interstitial. Identification of linked markers with advanced genomic technologies will aid in marker-assisted pyramiding of alien genes in cultivated wheat background.     

Silencing of puroindoline a alters the kernel texture in transgenic bread wheat

Grain hardness is an important end-use quality parameter of bread wheat, and one of the most important characters for quality improvement. The objective of this study was to further understand the function of puroindolines and the underlying mechanism in the formation of kernel texture. The highly efficient expression vector pUBPa harboring puroindoline a (Pina) was introduced into the bread wheat cultivar Zhongyou 9507-60 via biolistic transformation and transgenic plants were obtained. The integration of the foreign Pina gene was confirmed by PCR and genomic DNA Southern blot analysis. The levels of friabilin on the surface of water-washed starch granules varied among the transgenic lines. SDS-PAGE analysis of Triton X-114 extracted protein showed that the PINA protein was absent in three transgenic lines, indicating that the endogenous Pina gene most likely had been co-suppressed by the over-expression of the Pina transgene. SKCS kernel hardness and scanning electron microscopy analysis further confirmed the changes of kernel texture in these lines.     

Combined mutations in five wheat STARCH BRANCHING ENZYME II genes improve resistant starch but affect grain yield and bread-making quality

Increases in the proportion of amylose in the starch of wheat grains result in higher levels of resistant starch, a fermentable dietary fiber associated with human health benefits. The objective of this study was to assess the effect of combined mutations in five STARCH BRANCHING ENZYME II (SBEII) genes on starch composition, grain yield and bread-making quality in two hexaploid wheat varieties. Significantly higher amylose (∼60%) and resistant starch content (10-fold) was detected in the SBEII mutants than in the wild-type controls. Mutant lines showed a significant decrease in total starch (6%), kernel weight (3%) and total grain yield (6%). Effects of the mutations in bread-making quality included increases in grain hardness, starch damage, water absorption and flour protein content; and reductions in flour extraction, farinograph development and stability times, starch viscosity, and loaf volume. Several traits showed significant interactions between genotypes, varieties, and environments, suggesting that some of the negative impacts of the combined SBEII mutations can be ameliorated by adequate selection of genetic background and growing location. The deployment of wheat varieties with increased resistant starch will likely require economic incentives to compensate growers and millers for the significant reductions detected in grain and flour yields.     

Variation in polar lipid composition among near-isogenic wheat lines possessing different puroindoline haplotypes

The exact mechanism underlying wheat (Triticum aestivum L.) kernel hardness is unknown. Similar to puroindoline proteins, polar lipids are present on the surface of starch granules. The objective of this research was to determine the specific polar lipid species present on the surface of wheat starch from near-isogenic wheat lines that have different puroindoline haplotypes and endosperm hardness. Four near-isogenic wheat lines were used in this study, all derived from the soft cultivar Alpowa. Direct infusion tandem mass spectrometry was used to identify the lipid species in whole-meal, flour and starch samples. Endosperm hardness had no significant effect on the polar lipid contents in wheat whole-meal, a slight influence on the polar lipid contents of the flour fractions and a significant influence on the polar lipid composition of the polar lipids located on the surface of wheat starch. The greatest quantities of polar lipids on the starch-surface occurred when both puroindoline proteins were present in their wild-type form. Starch-surface polar lipid content dramatically decreased when one of the puroindoline proteins was null or if pin-B was in the mutated form. The least amount of polar lipids was present when pin-B was in its mutated form and pin-A was in its wild-type form.     

Polymorphism of Low Mr Glutenin Subunits in Triticum tauschii

A collection of 173 Triticum tauschii accessions was analysed to evaluate the variability of low molecular weight (M_r) glutenin subunits. These proteins were analysed by one-step one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and were divided into B-, C- and D-subunits in accordance with their electrophoretic mobility. Extensive polymorphism, both in the number and electrophoretic mobility, was detected in lowM_r glutenin subunits present in T. tauschii. Thirty different patterns for B-subunits and forty-three for C-subunits were identified, some of which were with identical electrophoretic mobility than those observed in hexaploid wheat. Glutenin subunits with the same electrophoretic mobilities of low M_r D-glutenin subunits as well as subunits encoded at the Glu-D4 and Glu-D5 loci, were also detected in accessions of T. tauschii. These results provide new basic knowledge regarding the genetics variability of the low M_r glutenin subunits, as well as their potential to create novel germplasm for the improvement of wheat quality in breeding programs.     

节节麦大穗大粒相关农艺性状的遗传分析

节节麦(Aegilops tauschii,DD)是六倍体普通小麦D基因组的祖先,其自然类群中含有丰富的抗逆、高产基因,利用其与四倍体硬粒小麦合成的六倍体小麦在现代小麦育种中得到了愈来愈多的应用。本课题在野生节节麦类群中发现了大穗、大粒材料AT462,利用其作母本与节节麦材料AT18(强分蘖)杂交;构建了F2、F3群体,通过调查亲本和群体单株的穗长、小穗数、粒长、粒宽和粒重等表型,对这些穗部性状进行了相关性分析和遗传分析。结果表明:(1)在F2和F3群体中,粒重、粒长与穗长之间不存在显著相关性,而且穗长与粒宽之间在两个群体中的平均相关系数绝对值小于0.1,粒重与小穗数之间的相关系数绝对值小于0.2,表明节节麦大粒相关性状不受穗长的影响,受小穗数影响也较小;(2)采用F2单世代分离分析的方法对节节麦AT462×AT18的F2群体大穗、大粒相关性状进行遗传分析,其中穗长受2对具有加性效应的主效基因控制;粒重和小穗数均同时受2对基因的加性效应、显性效应以及互作效应控制,其中加性效应占主导地位;粒长、粒宽均受2对基因的加性效应、显性效应以及互作效应控制,且三种效应较为均衡。这说明控制节节麦粒重、穗长、小穗数等产量性状相关基因的加性效应在遗传中占主导地位,在育种中较易利用,且其主效基因的遗传力达0.9。     

四川小麦品种(系)淀粉颗粒结合蛋白多态性分析

为了解四川小麦品种(系)淀粉颗粒结合蛋白的多样性,对66份四川小麦地方品种、100份新育成品种(系)以及21份小麦骨干亲本材料的淀粉颗粒结合蛋白进行了SDS-PAGE分析。结果表明,在187份供试材料中共分离出7种蛋白条带组合类型,10种不同的蛋白条带,其中5种条带在供试材料中检测到缺失和迁移率改变。114份材料表现为SGP-1A蛋白缺失,而在所有供试的四川小麦地方品种中该蛋白均表达。共4份材料在SGP-1B位点蛋白迁移率改变,18份材料的Wx-1B蛋白条带缺失,8份材料的Wx-1D蛋白条带缺失,仅有1份材料的Wx-1A蛋白条带缺失。通过与中国春缺体-四体(N7AT7B、N7DT7B、N4AT4B)、乌拉尔图小麦(AA)、节节麦(DD)、圆锥小麦(AABB)淀粉颗粒结合蛋白的比较,并结合质谱鉴定,进一步验证了所鉴定条带的准确性。本研究表明,四川小麦新育成品种(系)和骨干亲本比四川小麦地方品种具有更丰富的淀粉颗粒结合蛋白变异类型,鉴定出的变异材料可用于淀粉颗粒结合蛋白功能的研究和小麦淀粉品质育种。     

Pastamaking and breadmaking quality of soft-textured durum wheat lines

The effects of grain texture on pastamaking and breadmaking quality were studied in three F₈ soft-textured durum wheat lines (SDLs) containing wild-type alleles Pina-D1a and Pinb-D1a as compared with their hard durum sister lines (HDLs). SDLs homozygous for a small 5DS segment, less than 14.4 cM in size, accumulated puroindolines A (Pin-A) and B (Pin-B) and showed SKCS values (19.9-23.6) significantly lower than those (72.6-76.8) of their hard-textured counterparts lacking Pin-A and Pin-B. In addition, SDLs exhibited approximately 24% higher flour extraction rates compared with HDLs. Reducing the kernel hardness decreased farinograph water absorption, dough tenacity (P) and, accordingly, alveograph P/L ratio, but increased farinograph stability, mixing tolerance and dough extensibility (L). Spaghetti cooking quality, as determined by the sensory judgment of firmness, stickiness and bulkiness, was unaffected by the kernel hardness, whereas the loaf volume exhibited a 10% increase associated with kernel softening. Flour and semolina, but not spaghetti, from SDLs showed a substantial reduction in yellowness (b^*) and brownness (100 − L^*) likely due to their finer particle size compared with HDLs. Alleles Pina-D1a and Pinb-D1a may offer new perspectives for breeding dual purpose (pasta and bread) durum wheat varieties.     

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.