抗白粉病糯性小麦的多重PCR分子鉴定技术

为同时鉴定小麦糯性和白粉病抗性,本研究利用已知3对引物建立多重PCR体系,分别扩增WxA1、Wx-B1、Wx-D1和Pm21基因的分子标记,其目的片段大小分别为:230/265、854、204和1400 bp。经过对供试品种和部分F2分离群体的Wx蛋白进行SDS-PAGE电泳检测,其结果与多重PCR结果一致,证明该多重PCR体系准确可靠,可提高小麦糯性兼抗白粉病的选育效率。     

利用Wx基因分子标记辅助选择培育面条专用优质小麦

利用“中国春”及其缺体-四体对wx-B1基因的STS标记进行了定位,并对一些小麦品种及3个高代糯麦株系做了鉴定,结果与Wx蛋白的SDS-PAGE一致.用该STS分子标记和其它方法,从组合江苏白火麦×关东107的F2分离群体中筛选出8种WX基因型,其中3种基因型为自然界中所没有.采用桥梁亲本法,同时利用wx-B1基因的STS标记和显微镜检辅助选择,经过3代杂交转育获得了含wx-Blb的接近京411的4A单体代换系,为优质面条专用小麦品质育种提供了广泛的遗传材料.利用WX基因分子标记辅助选择,可以加快育种进程.     

在陕南圆锥小麦Wx蛋白亚基多态性研究中首次发现天然糯性类型

用双向SDS-PAGE和单向SDS-PAGE对六倍体 普通小麦(Triticum aestivum,AABBDD)Wx蛋白 的研究结果表明,在每个染色体组的第7同源群染 色体上有一个Wx位点:7A上的Wx-A1,7D上的 Wx-D1和从7B易位到4A上的Wx-Bl,因而六倍 体普通小麦有3种Wx蛋白.一些科研工作者筛选 到Wx-A1和Wx-B1缺失的“关东107”、Wx-D1缺 失的“白火麦”和一些Wx-B1缺失类型的材料.     

糯性胚乳小麦的选育

在自然界,大多数禾谷类作物,如玉米、水稻、高梁、粟、黍子等,都存在糯性类型.但是由于普通小麦是异源六倍体作物,在它的染色体7AS、4AS和7DS 上各有一个基因,即Wx-A1、Wx-B1 和Wx-D1控制Wx蛋白(淀粉粒束缚淀粉合成酶),Wx蛋白与直链淀粉的合成有关.当三个位点基因全部缺失或不表达时不能合成直链淀粉,只有支链淀粉、自然界不存在三个Wx基因同时缺失的小麦.所以迄今为止尚未发现自然界存在的糯性小麦.小麦面粉中直链淀粉含量是决定面条品质的一个重要因素.本研究以"两个部分糯性"材料作亲本,并结合花粉染色、籽粒剖面染色、SDS-PAGE电泳等手段,在杂种后代中选出了若干糯性小麦品系,定名为"农大糯麦"系列.     

优质新疆拉面品种品质评价的多重PCR体系构建与应用

新疆拉面是深受人们喜爱的特色面食之一,建立优质新疆拉面品质评价体系对其专用品种选育和评价具有重要意义。本研究构建了3套检测新疆拉面优质基因的多重PCR体系,并对46份新疆冬小麦(Triticum aestivum L.)进行了检测。体系Ⅰ可同时直接检测Ax2、Pinb-D1b和ω-secalin(1B·1R易位)3种基因,体系Ⅱ可同时直接检测两个位点Psy-A1(Psy-A1a、Psy-A1b、Psy-A1c)和Ppo-D1(Ppo-D1a、Ppo-D1b)的5种基因,体系Ⅲ可同时直接检测Glu-B3a、Wx-B1a和Wx-B1b3种基因,3套体系检测对照品种(系)的结果均与已知基因型完全一致。对46份新疆冬小麦的检测结果表明,Ax2、Pinb-D1b和不含ω-secalin(非1B·1R易位)基因出现的频率依次为30.4%、45.7%和78.3%,Psy-A1a、Psy-A1b、Psy-A1c、Ppo-D1a和Ppo-D1b基因的频率分别为94.5%、4.3%、2.2%、91.3%和8.7%,Glu-B3a、Wx-B1a和Wx-B1b基因的频率依次为21.7%、91.3%和8.7%;其中,与新疆拉面优质性状相关的5个基因Ppo-D1a、不含ω-secalin、Pinb-D1b、Glu-B3a和Ax2的频率明显高于全国平均水平;共检测到19种优质拉面基因的组合类型,其中含1、2、3、4和5个优质基因的组合类型依次占参试品种(系)的13.0%、32.6%、26.1%、23.9%和4.3%,没有发现同时含6或7个优质基因的品种(系),出现频率最高的优质基因组合类型为Ppo-D1a/不含ω-secalin(非1B·1R易位)、Ppo-D1a/Glu-B3a/不含ω-secalin和Ppo-D1a/Ax2/Pinb-D1b/不含ω-secalin。研究结果表明,本研究建立的3套多重PCR体系,结果稳定可靠,可作为新疆拉面品种品质性状快速评价的方法;利用本研究构建的多重PCR体系和筛选出的含优质基因(组合)的品种(系),开展小麦品质评价和分子聚合育种,将会提高新疆拉面品种评价和选育的效率。     

四川小麦品种贮藏蛋白位点及SSR分析*

利用种子贮藏蛋白和SSR标记研究了四川近20多年育成的小麦(Triticum aestivum)品种第1和第6同源群染色体的蛋白基因位点及遗传多样性。结果表明：供试的47个小麦品种共检测出47条醇溶蛋白条带，其中39条具有多态性，占82．98％；高分子量(HMW)谷蛋白亚基共出现7种亚基和11种亚基组合，表明四川主栽小麦品种在醇溶蛋白位点上存在广泛的变异，而HMW谷蛋白亚基遗传基础较狭窄。SSR结果表明，在21个位点中有8个(38．1％)位点具多态性，共检测到19个等位变异，供试品种在：DNA水平上存在一定的变异。聚类分析表明：两种标记均可将供试品种(包括中国春)分为三大类。通过Mantel检测，两种标记的分析结果间有显著的相关性，反映了在蛋白质和DNA水平上的结果可以互相补充，增加可靠性。     

新疆小麦地方品种资源HMW-GS的遗传多样性组成分析

为了明确新疆小麦地方品种高分子量麦谷蛋白亚基的遗传多样性,并为小麦品质改良提供基础材料,利用十二烷基硫酸钠聚丙烯酰胺凝胶电泳(SDS-PAGE) 技术,分析了源自新疆地区的282份小麦地方品种的高分子量麦谷蛋白亚基组成。结果表明,在Glu-A1、Glu-B1和Glu-D1位点上的等位变异分别为3、6和 5种,三个位点上的优势亚基依次为null、7+8和2+12,其频率分别是75.5%、90.8%和72.0%。在Glu-1位点共检测到20种亚基组合,其中(null, 7+8, 2+12)组合的频率最高,为52.8%, 其次是(null, 7+8, 2.6+12)和(2*, 7+8, 2+12)组合,其频率分别为14.1%和11.0%,其它亚基组合的频率均低于10%。另外,在Glu-D1位点上还检测到一个新的亚基2.6+12。在供试的282份新疆地方品种中发现了两份具有优质亚基组合的材料,它们的亚基组成为(2*, 7+9, 5+10)和(1, 7+9, 5+10),这些地方品种可作为改良小麦品质性状的重要遗传资源。     

黑龙江春小麦脂肪氧化酶活性基因多态性分析

本研究利用新筛选和开发的脂肪氧化酶(Lipoxygenase,LOX)基因分子标记技术,对125份黑龙江省春小麦品种进行研究。结果显示,SSR标记Xwmc312在QLpx.caas-1AL位点上,扩增出Xwmc312-247,Xwmc312-235,Xwmc312-2273种等位基因,分布频率分别是59.06%,22.05%,18.11%。两对显性互补STS标记在Ta LOX-B1位点上,扩增出Ta Lox-B1a和Ta Lox-B1b等位基因,分布频率分别是11.02%、88.98%,以Ta Lox-B1b基因型为主。2个位点不同等位基因组合共有6种,Xwmc312-247/Ta LOX-B1b分布频率最高(51.18%),Xwmc312-235/Ta LOX-B1a分布频率最低(1.58%),其它4种组合型介于二者之间。这表明黑龙江省小麦品种中缺少LOX高活性组合型(Xwmc312-235/Ta LOX-B1a)。上述结果为当地培育高白度小麦新品种提供了分子遗传学信息。     

小麦粒重相关基因TaCYP78A16的克隆和CAPS标记开发

粒重是小麦(Triticum aestivum)产量的重要构成要素,为了开发小麦粒重性状相关的功能标记,本研究通过小麦全基因组预测并克隆得到1个潜在粒重相关基因:小麦细胞色素P450单加氧酶基因(Triticum aestivum cytochrome P450 78A16, TaCYP78A16; GenBank No. MH572527),并对其进行基因结构、表达模式、等位变异分析和粒重性状相关功能标记开发。结果表明,TaCYP78A16基因在小麦幼穗和籽粒发育初期高表达,可能参与籽粒发育、影响粒重;对30个小麦品种中TaCYP78A16基因编码区和启动子等位变异进行分析,发现仅TaCYP78A16-A启动子16Ap检测到7个位点的等位变异;根据7个等位变异中的2个SNP位点(SNP2, SNP3)开发了单核苷酸多态性-酶切扩增多态性序列(single nucleotide polymorphisms-cleaved amplified polymorphic sequences, SNP-CAPS)分子标记CAPS-16Ap,该分子标记可将30个小麦品种16Ap序列分成3种基因型:16Ap-Hap1、16Ap-Hap2和16Ap-Hap3;进一步在323个小麦品种中进行验证,结果显示,CAPS-16Ap标记可用于小麦16Ap序列3种基因型的鉴定。本研究将有助于小麦分子标记辅助选择育种。     

俄引与黑龙江春小麦多酚氧化酶活性基因类型的比较

多酚氧化酶(PPO)活性与小麦面粉白度密切相关,为了从外引资源中筛选出更多优良基因型用于品种改良,本研究利用与PPO活性有关的2个遗传位点相连锁的3对STS分子标记,对250份引自俄罗斯和125份黑龙江主栽春小麦品种进行分析。结果显示,对于2AL染色体上的共显性STS标记PPO18而言,俄引品种中182份(72.8%)品种扩增出685 bp特异谱带,即高PPO活性的PPO-2Aa等位基因;68份(27.2%)品种扩增出876 bp特异条带,即低PPO活性的PPO-2Ab等位基因。黑龙江品种中76份(60.8%)品种扩增出685 bp特异谱带,45份(36%)品种扩增出876 bp特异谱带,4份(3.2%)品种未扩增出谱带。对于2DL染色体上的显性互补STS标记PPO16/PPO29而言,俄引品种有109份(43.6%)品种扩增出低PPO活性的PPO-2Da等位基因,141份品种(56.4%)扩增出高PPO活性的PPO-2Db等位基因;而黑龙江品种有60份(48%)品种扩增出低PPO活性的PPO-2Da基因型,65(52%)份品种扩增出高PPO活性的PPO-2Db基因型。2个位点不同等位基因组合共有5种,且在俄罗斯与黑龙江品种间存在不同程度的差别。其中,黑龙江品种中双低PPO活性等位基因组合PPO-2Ab/PPO-2Da较俄罗斯的多5.6%。研究结果为俄引资源用于黑龙江小麦品种改良提供了分子遗传学信息。     

Interactions Among Wx Genes and Effects of a Mutated Wx‐D1e Allele on Starch Properties in Wheat

The waxy mutant wheat Tanikei A6599‐4 contains little amylose and exhibits a stable hot paste viscosity. It has null alleles at the Wx‐A1 and Wx‐B1 loci and a mutated allele at the Wx‐D1 locus (Wx‐D1e). From the cross‐combination of Kanto 123 (normal amylose line) and Tanikei A6599‐4, 51 DH (doubled haploid) lines were produced and their genotypes were determined by SDS‐PAGE and a derived cleaved amplified polymorphic sequence (dCAPS) analysis. Eight genotypes were obtained at the expected ratio. Using a Rapid Visco Analyser (RVA), all the lines with the same genotype as Tanikei A6599‐4 showed a stable hot paste viscosity. The other lines did not show a stable hot paste viscosity regardless of the presence of the Wx‐D1e allele. When two genotypes with the same Wx‐A1 and Wx‐B1 alleles were compared, the one with Wx‐D1e contained less amylose and exhibited a lower final viscosity and a lower setback with RVA. Although the Wx‐D1e allele produces an almost inactive Wx protein, these findings suggest that this allele contributes at some level to starch synthesis.     

Physicochemical and Thermal Characteristics of Starch Isolated from a Waxy Wheat Genotype Exhibiting Partial Expression of Wx Proteins

A unique wheat genotype carrying waxy‐type allelic composition at the Wx loci, Gunji‐1, was developed, and its starch properties were evaluated in comparison to parental waxy and wild‐type wheat varieties. Gunji‐1 was null in all three of the Wx genes but exhibited a lower level of Wx proteins than the wild‐type. Starch amylose content and cold water retention capacity were 10.1 and 70.5% for Gunji‐1, 4.2 and 76.6% for waxy, and 27.9 and 65.0% for wild‐type, respectively. No significant differences were observed in microstructure, granule size distribution, and X‐ray diffractograms of the starch granules isolated from Gunji‐1 compared with those of waxy and wild‐type wheat varieties. Starch pasting peak, breakdown, and setback viscosities and peak temperature of Gunji‐1 were intermediate between waxy and wild‐type wheat. In starch gel hardness, Gunji‐1 (1.1 N) was more similar to waxy wheat (0.5 N) than to the wild‐type variety (17.6 N). Swelling power, swelling volume, paste transmittance during storage, and gelatinization enthalpy of Gunji‐1 were lower than those of waxy wheat but greater than those of wild‐type wheat. Retrogradation of starch stored for one week at 4°C expressed with DSC endothermic enthalpy was absent in the waxy wheat variety, whereas Gunji‐1 exhibited both retrogradation of amylopectin and amylose‐lipid complex melting similar to the wild‐type parent, even though enthalpies of Gunji‐1 were much smaller than the wild‐type parent.     

Genetic Effects of Wx Allele Combinations on Apparent Amylose Content in Tropical Hybrid Rice

Apparent amylose content (AAC), as one of the most important quality traits of rice grain, is primarily controlled by the Wx gene, which encodes a granule‐bound starch synthase. Effects of putative alleles of Wx of tropical rice hybrids generated from parents with three different nonglutinous Wx alleles (Wx ^a , Wx ^b , and Wx ⁱⁿ ) were examined in a multienvironment trial. Genotypes of Wx ^b /Wx ⁱⁿ and Wx ⁱⁿ /Wx ⁱⁿ were associated with intermediate AAC (20.2–23.7%), and genotype of Wx ^a /Wx ^a was associated with high AAC (24.9–28.0%). Wx alleles of Wx ⁱⁿ /Wx ⁱⁿ could be the most favorable combinations in selecting hybrid parents with desirable intermediate amylose content (20–25%) for rice consumers of South and Southeast Asian countries. Genotype and genotype × environment interaction were the major contributing factors to the variation in parental accessions’ and hybrids’ AAC, and in terms of AAC, hybrids were more sensitive than parental varieties to environment. Genotypes of Wx ^a /Wx ^a , Wx ^a /Wx ⁱⁿ , and Wx ⁱⁿ /Wx ⁱⁿ showed higher AAC performance in the wet season than in the dry season.     

Development of taxon-specific sequences of common wheat for the detection of genetically modified wheat

Qualitative and quantitative Polymerase Chain Reaction (PCR) systems aimed at the specific detection and quantification of common wheat DNA are described. Many countries have issued regulations to label foods that include genetically modified organisms (GMOs). PCR technology is widely recognized as a reliable and useful technique for the qualitative and quantitative detection of GMOs. Detection methods are needed to amplify a target GM gene, and the amplified results should be compared with those of the corresponding taxon-specific reference gene to obtain reliable results. This paper describes the development of a specific DNA sequence in the waxy-D1 gene for common wheat (Triticum aestivum L.) and the design of a specific primer pair and TaqMan probe on the waxy-D1 gene for PCR analysis. The primers amplified a product (Wx012) of 102 bp. It is indicated that the Wx012 DNA sequence is specific to common wheat, showing homogeneity in qualitative PCR results and very similar quantification accuracy along 19 distantly related common wheat varieties. In Southern blot and real-time PCR analyses, this sequence showed either a single or a low number of copy genes. In addition, by qualitative and quantitative PCR using wx012 primers and a wx012-T probe, the limits of detection of the common wheat genome were found to be about 15 copies, and the reproducibility was reliable. In consequence, the PCR system using wx012 primers and wx012-T probe is considered to be suitable for use as a common wheat-specific taxon-specific reference gene in DNA analyses, including GMO tests.     

Reduced Amylose Effects on Bread and White Salted Noodle Quality

Amylose content in wheat endosperm is controlled by three Wx loci, and the proportion of amylose decreases with successive accumulation of Wx null alleles at the three loci. The proportion of amylose is believed to influence end‐use quality of bread and Asian noodles. The objectives of this study were to determine influence of the allelic difference at Wx‐B1 locus on bread quality, bread firmness, and white salted noodle texture in a spring wheat cross segregating for the Wx‐B1 locus and in a set of advanced spring wheat breeding lines differing in allelic state at the Wx‐ B1 locus. In addition, we examined the relationship between amylose content and flour swelling properties on bread and noodle traits. Fifty‐four recombinant inbred lines of hard white spring wheat plus parents were grown in replicated trials in two years, and 31 cultivars and breeding lines of hard spring wheat were grown in two locations. Bread and white salted noodles were processed from these trials. The presence of the Wx‐B1 null allele reduced amylose content by 2.4% in a recombinant inbred population and 4.3% in a survey of advanced breeding lines and cultivars compared with the normal. The reduced amylose was accompanied by an average increase in flour swelling power (FSP) for the Wx‐B1 null group of 0.8 g/g for the cross progeny and 2.3 g/g for the cultivar survey group. The Wx‐B1 allelic difference did not affect flour protein in cross progeny where the allelic difference was not confounded with genetic background. Bread from the Wx‐B1 null groups on average had increased loaf volume and was softer than the normal group for the cross progeny and cultivar survey group. The Wx‐B1 allelic difference altered white salted noodle texture, most notably noodle springiness and cohesiveness where the Wx‐B1 null groups was more springy and more cohesive than the normal groups for both sets of genetic materials. Flour protein was more highly related to loaf volume than were FSP or amylose. Both flour protein and FSP were positively related to noodle textural traits, but especially noodle springiness and cohesiveness.     

Effects of Allelic Variations in Wx‐1, Glu‐D1, Glu‐B3, and Pinb‐D1 Loci on Flour Characteristics and White Salted Noodle‐Making Quality of Wheat Flour

Doubled haploid wheat lines developed from a cross between a hard white winter wheat variety of normal starch endosperm and a waxy wheat variety were used to determine the effects of allelic variation in Wx‐1, Glu‐D1, Glu‐B3, and Pinb‐D1 loci on physiochemical properties of flour, noodle dough properties, and textural quality of cooked noodles. Milling yield, damaged starch content, protein content, and SDS sedimentation volume of flour were influenced the most by allelic composition of Pinb‐D1 loci, less by Wx‐1 loci, and least by Glu‐B3. Wheat lines carrying Pinb‐D1b or Glu‐B3h alleles exhibited higher milling yield and damaged starch content of flour than those with Pinb‐D1a and Glu‐B3d alleles. Wheat lines carrying the Pinb‐D1b allele were higher in protein content and SDS sedimentation volume than those carrying Pinb‐D1a. Mixograph water absorption was largely influenced by allelic composition of Wx‐1 loci, whereas mixograph mixing time and mixing tolerance were predominantly determined by allelic composition of Glu‐D1 loci. Amylose content and pasting properties of starch were mainly determined by allelic composition of Wx‐1 loci with little influence by allelic compositions of Glu‐D1, Glu‐B3, and Pinb‐D1 loci. Allelic composition of Wx‐1 loci contributed 53.4% of the variation in optimum water absorption of noodle dough and 26.7% of the variation in thickness of the noodle dough sheet. The variation of 7.8% in optimum water absorption of noodle dough was contributed by the allelic composition of Pinb‐D1 loci. Allelic composition of Wx‐1 loci was responsible for 73.2, 74.4, and 59.6% in the variation of hardness, springiness, and cohesiveness of cooked noodles, respectively. Cohesiveness of cooked noodles was also influenced by the allelic compositions of Glu‐B3 and Pinb‐D1 loci to a smaller extent.     

Single Kernel Near‐Infrared Analysis of Tetraploid (Durum) Wheat for Classification of the Waxy Condition

Plant breeding programs are active worldwide in the development of waxy hexaploid (Triticum aestivum L.) and tetraploid (T. turgidum L. var. durum) wheats. Conventional breeding practices will produce waxy cultivars adapted to their intended geographical region that confer unique end use characteristics. Essential to waxy wheat development, a means to rapidly and, ideally, nondestructively identify the waxy condition is needed for point‐of‐sale use. The study described herein evaluated the effectiveness of near‐infrared (NIR) reflectance single‐kernel spectroscopy for classification of durum wheat into its four possible waxy alleles: wild type, waxy, and the two intermediate states in which a null allele occurs at either of the two homologous genes (Wx‐1A and Wx‐1B) that encodes for the production of the enzyme granule bound starch synthase (GBSS) that controls amylose synthesis. Two years of breeders' samples (2003 and 2004), corresponding to 47 unique lines subdivided about equally into the four GBSS genotypes, were scanned in reflectance (1,000–1,700 nm) on an individual kernel basis. Linear discriminant analysis models were developed using the best set of four wavelengths, best four wavelength differences, and best four principal components. Each model consistently demonstrated the high ability (typically >95% of the time) to classify the fully waxy genotype. However, correct classification among the three other genotypes (wild type, wx‐A1 null, and wx‐B1 null) was generally not possible.     

Effect of Variation in Amylose Content and Puroindoline Composition on Bread Quality in a Hard Spring Wheat Population

Milling and breadbaking quality of hard‐textured wheat may be influenced by alternative alleles at the Wx loci controlling percent amylose in the endosperm, and the puroindoline (pin) loci controlling grain hardness. For this experiment, we developed recombinant inbred lines (RIL) from a cross between Choteau spring wheat cultivar and experimental line MTHW9904. Choteau has the PinB‐D1b mutation conferring grain hardness and the Wx‐B1a allele at the Wx‐B1 locus conferring wild‐type amylose content. MTHW9904 has the PinA‐D1b allele conferring grain hardness and the Wx‐B1b allele conferring lower amylose content, causing a partial waxy phenotype. RIL with the PinB‐D1b mutation (n = 49) had significantly softer kernels, higher break flour yield, and higher loaf volume than lines with the PinA‐D1b mutation (n = 38). Lines with partial waxy phenotype due to Wx‐B1b (n = 43) had significantly lower kernel weight, lower amylose content, and higher flour swelling power than lines with wild‐type starch due to Wx‐B1a (n = 51). These results provide additional evidence for the positive effect of PinB‐D1b on bread quality in hard wheats, while genotype at Wx‐B1 was generally neutral for bread quality in this population. Interactions between the Pin and Wx loci were minimal.     

Characterization of the Wx gene in diploid Aegilops species and its potential use in wheat breeding

Wx gene encodes for the granule-bound starch synthase I or waxy protein, which is the sole enzyme responsible for amylose synthesis in wheat seeds. The Aegilops species, which are related to wheat, could be important sources of variation in this gene. In addition to its role in starch quality, this gene has been used in phylogenetic studies of wheat. The current study evaluated the variability of Wx gene in seven diploid species of Aegilops genus and compared their nucleotide sequences with the wheat homeologous genes. Nineteen new Wx alleles were found in the seven species evaluated. The alleles detected in two species of the Sitopsis section, Ae. searsii and Ae. speltoides, were related to the Wx-B1 gene of wheat. Two more of the Sitopsis species did not appear to be associated with this genome, whereas the remaining species were related to the Wx-D1 gene of wheat. The results showed an important variation of the Wx gene present in the Aegilops genus, and the 19 new Wx alleles detected could enlarge the genetic pool of wheat.     

Protein and Quality Characterization of Complete and Partial Near‐Isogenic Lines of Waxy Wheat

The objective of this study was to evaluate protein composition and its effects on flour quality and physical dough test parameters using waxy wheat near‐isogenic lines. Partial waxy (single and double nulls) and waxy (null at all three waxy loci, Wx‐A1, Wx‐B1, and Wx‐D1) lines of N11 set (bread wheat) and Svevo (durum) were investigated. For protein composition, waxy wheats in this study had relatively lower albumins‐globulins than the hard winter wheat control. In the bread wheats (N11), dough strength as measured by mixograph peak dough development time (MDDT) (r = 0.75) and maximum resistance (R_max) (r = 0.70) was significantly correlated with unextractable polymeric protein (UPP), whereas in durum wheats, moderate correlation was observed (r = 0.73 and 0.59, respectively). This may be due to the presence of high molecular weight glutenin subunits (HMW‐GS) Dx2+Dy12 at the Glu‐D1 locus instead of Dx5+Dy10, which are associated with dough strength. Significant correlation of initial loaf volume (ILV) to flour polymeric protein (FPP) (r = 0.75) and flour protein (FP) (r = 0.63) was found in bread wheats, whereas in durum wheats, a weak correlation of ILV was observed with FP (r = 0.09) and FPP (r =0.51). Significant correlation of ILV with FPP in bread wheats and with % polymeric protein (PPP) (r = 0.75) in durum lines indicates that this aspect of end‐use functionality is influenced by FPP and PPP, respectively, in these waxy wheat lines. High ILV was observed with 100% waxy wheat flour alone and was not affected by 50% blending with bread wheat flour. However, dark color and poor crumb structure was observed with 100% waxy flour, which was unacceptable to consumers. As the amylopectin content of the starch increases, loaf expansion increases but the crumb structure becomes increasingly unstable and collapses.