四川小麦品种高、低分子量麦谷蛋白基因和1B/1R易位的分子标记鉴定

为给四川小麦品质育种提供参考信息,利用7个HMW-GS、17个LMW-GS和1个1B/1R易位的特异分子标记,对105份2000年后育成的四川小麦品种进行上述基因检测。结果表明:(1)针对HMWGS,在Glu-A1位点,含Ax2*的品种有2份,频率为1.9%;在Glu-B1位点,含Bx7、Bx20、Bx17、By8和By9的品种分别有73、26、4、45和30份,频率分别为69.5%、24.8%、3.8%、42.9%和28.6%,未检测到含Bx7OE的品种;在Glu-D1位点,含Dx5的品种有65份,频率为61.9%。(2)针对LMW-GS,在Glu-A3位点,含Glu-A3a、Glu-A3b、Glu-A3c、Glu-A3d和Glu-A3f的品种分别有2、2、63、29和9份,频率分别为1.9%、1.9%、60.0%、27.6%和8.6%,未检测到含Glu-A3e和Glu-A3g的品种;在Glu-B3位点,含Glu-B3b、Glu-B3d、Glu-B3f、GluB3g和Glu-B3i的品种分别有18、10、1、75和1份,频率分别为17.1%、9.5%、1.0%、71.4%和1.0%,未检测到含Glu-B3a、Glu-B3c、Glu-B3e和Glu-B3h的品种。(3)含1B/1R易位的品种有36份,频率为34.3%。(4)组合6种和5种以上优质基因的品种分别有2份(频率为3.8%)和15份(频率为14.3%)。可利用这些品种作为亲本,在四川小麦品质育种中逐步导入优质基因Ax2*、Bx7、By8、Dx5、Glu-A3d、Glu-B3d、Glu-A3b和Glu-B3b,并淘汰1B/1R易位,优化四川小麦面筋优质基因组成。     

冬小麦品种高低分子量麦谷蛋白亚基的分子标记检测

为了通过育种手段尽快改良小麦加工品质,利用Dx5、By8、By9、By16、Glu-A3、Glu-B3和1B.1R的特异性分子标记对221份中国冬小麦品种（系）进行HMW-GS、LMW-GS基因的等位变异及1B.1R易位系检测,结果表明：（1）在所检测的小麦品种（系）中,含Dx5、By8、By9的材料依次为58、79、119份,频率依次为26.2%、35.7%、53.8%;未检测到含By16的材料。（2）在所检测的小麦品种（系）中,Glu-A3位点上,含Glu-A3a、Glu-A3b、Glu-A3c、Glu-A3d的材料依次为30、1、111、79份,频率依次为13.6%、0.5%、50.2%、35.7%;未检测到携带Glu-A3e、Glu-A3f、Glu-A3g的材料;Glu-B3位点上,含Glu-B3d、Glu-B3g、Glu-B3f、Glu-B3h的材料较多,依次为64、47、18、11份,频率依次为29.0%、21.3%、8.1%、5.0%,含Glu-B3a、Glu-B3b、Glu-B3c、Glu-B3i的材料很少,依次为1、3、2、4份,频率依次为0.5%、1.4%、0.9%、1.8%;含1B.1R易位系的材料（即Glu-B3j类型）71份,频率为32.1%;未检测到含Glu-B3e的材料。（3）在所检测的小麦品种（系）中含最优亚基组合By8、Dx5、GluA3d、GluB3d的材料只有2份,频率为0.9%,说明聚合多个优良基因的小麦品质改良工作急需加强。     

陕西小麦Glu-A3和Glu-B3位点等位变异的检测和分析

低分子量谷蛋白亚基（LMW-GS）与小麦品质密切相关。为了给陕西小麦的品质改良提供参考依据,采用STS分子标记,检测了175份陕西小麦品种（系）Glu-A3和Glu-B3位点的等位变异组成。结果表明,陕西小麦Glu-A3位点存在4种等位变异,即Glu-A3a、Glu-A3b、Glu-A3c和Glu-A3d,分别占12.6%、1.7%、58.3%和27.4%;Glu-B3位点存在8种等位变异,即Glu-B3a、Glu-B3b、Glu-B3d、Glu-B3e、Glu-B3f、Glu-B3g、Glu-B3i和Glu-B3j,分别占4.6%、2.9%、45.7%、0.6%、2.9%、8.5%、4.0%和30.8%。在陕西不同地区小麦之间,两个位点等位变异的种类、组合及其分布比例存在差异,这可能与地区间不同的自然地理环境、饮食习惯、育种目标及亲本选择有关。     

新疆小麦品种Glu-A3和Glu-B3位点等位变异的分布

为给新疆小麦品质育种提供理论依据,利用Glu-A3、Glu-B3位点上的17个STS标记检测了185份新疆冬、春小麦品种Glu-A3和Glu-B3位点的等位变异。结果表明,新疆小麦品种以Glu-A3c、Glu-B3a和Glu-B3j亚基为主,其分布频率分别为64.86%、22.70%和17.84%。新疆冬、春小麦品种在Glu-A3位点上均以Glu-A3c亚基为主,分布频率分别为63.30%和67.11%;在Glu-B3位点上,新疆冬、春小麦品种分别以Glu-B3j和Glu-B3a为主,分布频率分别为22.02%和26.32%。新疆冬、春小麦农家品种亚基类型较少,冬小麦农家品种仅有5种类型（以Glu-A3c和Glu-B3i为主）,春小麦农家品种有10种类型（以Glu-A3c和Glu-B3d为主）。引进品种和自育品种亚基类型丰富,冬小麦引进品种以Glu-A3c和Glu-B3i为主,分布频率为12.84%和6.42%;春小麦引进品种以Glu-A3c和Glu-B3j为主,分布频率为17.11%和6.58%。冬小麦自育品种以Glu-A3c和Glu-B3j亚基类型为主,分布频率为45.87%和18.35%;春小麦自育品种以Glu-A3c和Glu-B3a亚基类型为主,分布频率为36.84%和18.42%。     

黄淮麦区小麦品种高分子量谷蛋白亚基组成分析

对黄淮麦区育成推广品种(59个)、2003～2004年度国家黄淮南片和江苏省区试参试品种(42个)、徐州农科所育成的高代品系以及一些育种亲本材料,共计309个品种(材料)的高分子量谷蛋白亚基组成进行了分析.结果共发现了32个亚基组成类型和16个等位基因变异.在Glu-A1位点发现了Glu-A1a、Glu-A1b、Glu-A1c 3个等位基因;在Glu-B1位点发现了Glu-B1a、Glu-B1b、Glu-B1c、Glu-B1d、Glu-B1e、Glu-B1f、Glu-B1g、Glu-B1h、Glu-B1i、Glu-B1k共10个等位基因;在Glu-D1位点发现了Glu-D1a、Glu-D1b、Glu-D1d 3个等位基因.以Glu-B1位点的变异最为丰富.在这3个位点上分别以等位基因Glu-A1c(null)、Glu-B1b(7 8)和Glu-D1a(2 12)为主,其出现频率分别为58.58%、58.90%和77.99%.高分子量谷蛋白亚基组成以(null,7 8,2 12)和(1,7 8,2 12)为主,分别占所有品种的32.69%和16.18%.在育成推广品种和参试品种中,等位基因变异均为11个;而亚基组成类型则分别为16个和13个.优质高分子量谷蛋白亚基5 10在所有材料、59个已审定推广品种和42个参试品种中的出现频率分别为20.4%、27.1%%和21.4%,频率均较低.这表明新近育成的品种在优质亚基的构成上并未取得较大进展,优质强筋小麦的品质育种还有较大的发展空间.试验结果也表明,黄淮冬麦区小麦品种的高分子量谷蛋白亚基组成类型和等位基因变异较为丰富,但其变异分布很不均匀,存在明显的优势亚基和组成类型.     

小麦体细胞杂种渐渗系F6代高分子量谷蛋白亚基组成与位点变异研究

为了发掘新的小麦高分子量谷蛋白用于面粉优质育种工作,本文测定了小麦/长穗偃麦草体细胞杂种共322个株系的高分子量麦谷蛋白亚基（HMW-GS）组成,并根据Payne等人1987年制定的小麦品质评分标准进行了品质评分。结果表明,体细胞杂种株系在Glu–A1,Glu–B1和Glu–D1位点上的遗传变异率分别为0.52,0.58和0.46,一共出现了27种不同的亚基组成形式,其中H1AxNull,H1Bx7+H1By9,H1Dx2+H1Dy12（同亲本小麦济南177）出现的频率最高,而H1Ax2*,H1Bx7+H1By8+H1By9,H1Dx2+H1Dx5+H1Dy12出现的频率最低;H1Dx5+H1Dy12出现的频率约为33.5%;在与优质可能相关的亚基组合当中,H1Bx13+H1By16出现的频率约为31.1%。由于1Dx5+1Dy12尚未有品质评分,因此,部分株系无法给出分数。该实验结果表明通过体细胞杂交可以产生大量的高分子量谷蛋白亚基/组合变异,这将有助于今后小麦面粉品质育种工作。     

高分子量麦谷蛋白亚基组成及其与小麦品质性状的关系分析

为进一步明确小麦高分子量麦谷蛋白亚基(HMW-GS)与小麦品质性状的关系,以黄淮麦区的127份小麦品种(系)为材料,利用SDS-PAGE技术、近红外谷物分析仪、粉质仪和拉伸仪等对其进行HMW-GS鉴定和品质检测。结果表明,参试材料在 Glu-A1、 Glu-B1和 Glu-D1 3个位点上分别检测到2(x1、x-null)、4(x7+y8、x7+y9、x14+y15、x17+y18)、2(x5+y10、x2+y12)种不同的亚基类型,其中x1、x7+y9、x5+y10在各自位点上出现的频率均最高,分别为70.1%、42.5%和51.2%;共发现有14种HMW-GS组合类型,其中1Ax1/1Bx7+1By8/1Dx5+1Dy10和1Ax1/1Bx7+1By9/1Dx2+1Dy12出现的频率较高,分别为18.9%和17.3%。1Ax1、1Bx7+1By8、1Bx17+1By18、Dx5+1Dy10亚基对蛋白质、沉降值、稳定时间、最大抗延阻力和拉伸面积等品质性状有显著的正向效应,而1Bx14+1By15亚基对除蛋白质和湿面筋以外的其他品质性状有负向效应。携带1Ax1/1Bx7+1By8/1Dx5+1Dy10品种(系)的被测品质性状显著高于携带其他组合类型的品种(系),其次是携带1Ax1/1Bx17+1By18/1Dx5+1Dy10的品种(系),而携带1Ax-null/1Bx7+1By9/1Dx2+1Dy12和1Ax-null/1Bx14+1By15/1Dx5+1Dy10品种(系)的各个品质性状显著低于携带其他组合类型的品种(系)。该结果可为进一步提高优质亚基的育种利用率和我国小麦品质的遗传改良提供参考依据。     

新疆冬小麦谷蛋白亚基组成及其与新疆拉面加工品质的关系

为给新疆冬小麦品质育种提供参考依据,选取109份新疆冬小麦品种(系),研究了其麦谷蛋白亚基组成及其与新疆拉面加工品质的关系.结果表明,新疆冬小麦品种(系)麦谷蛋白亚基以N、7+8、2+12、Glu-A3c、Glu-B3a和Glu-B3j为主,在其各自位点的分布频率分别为40.37％、51.38％、54.13％、63.30％、20.18％和22.02％.籽粒蛋白质平均含量和湿面筋平均含量分别为15.38％和33.18％,变异系数较小,分别为6.70％和6.33％;沉淀值和8min宽度变异系数较大,分别为22.85％和61.27％.就单个亚基对新疆拉面加工品质的贡献而言,Glu-A1位点,l＞2*＞N;Glu-B1位点,7+8＞6+8＞7+9;Glu-D1位点,5+10＞2+12;Glu-B3位点,Glu-B3g＞ Glu-B3a＞Glu-B3i＞Glu-B3d＞ Glu-B3j;合有1、7+8、5+10和Glu-A3c亚基的品种(系)在拉面评价中具有较高得分.在新疆拉面专用品种选育时,应避免亲本含有N、6+8和Glu-B3j等亚基的使用.     

甘肃小麦品种(系)HMW-GS遗传变异分析

为了了解甘肃省小麦品种HMW-GS的遗传变异和组成，为甘肃优质专用小麦品种筛选和品种改良提供依据,采用SDS-PAGE法，分析了254份甘肃省小麦材料(育成品种(系)和农家品种)Glu-1位点的HMW-GS变异，共检测到22种HMW-GS变异，Glu-A1位点3种，Glu-B1位点11种，Glu-D1位点8种。其中110个育成品种(系)的15种HMW-GS有27种亚基组合类型。Glu-A1位点有2种亚基，47．3％的品种该位点具有优质亚基；Glu-B1位点有7种亚基，76．4％的品种具优质亚基；Glu-D1位点有6种亚基，32．7％的品种具优质亚基。14．5％的品种(n：15)Glu-1位点具优质亚基。144份农家品种的18种HMW-GS共有29种亚基组合形式，Glu-A1位点有3种亚基,Glu-B1位点有9种亚基，Glu-D1位点有6种亚基，无优质亚基组合。     

小麦HMW GS检测方法的优化及应用

为了准确快速鉴定小麦品种的HMW-GS组成,以18个已知HMW-GS组成的品种为对照,将4种不同浓度分离胶的SDS-PAGE与分子标记(Bx7、Bx7OE和By 8)相结合,构建一套适于检测HMW-GS组成的方法,并用该方法检测214份陕西小麦品种(系)的HMW-GS组成。4种分离胶浓度中,除了亚基7、7*与7OE和8与8*外,9%的分离胶可以很清楚地分离Glu1-位点的其他常见亚基,结合分子标记(Bx7、Bx7OE和By 8)检测对照品种,结果与已知亚基(基因)一致。用分离胶浓度为9%的SDS-PAGE结合分子标记(Bx7、Bx7OE和By 8)方法对陕西品种(系)检测结果表明,Glu-A1、Glu-B1和Glu-D1分别有3、8和3个亚基种类,共28种亚基组合类型。以1、Null、7+9、7+8、7+8*、14+15、2+12和5+10为主要亚基类型,频率分别为55.6%、41.6%、43.9%、26.2%、10.3%、15.4%、79.0%和12.6%;同时在Glu-B1位点发现7+8*和6+8*亚基。该方法可以快速准确地评价小麦HMW-GS组成,有效区分Glu-B1位点的亚基7与7OE,8与8*,鉴定结果稳定可靠。     

57份陕西新育成小麦品种（系）HMW-GS组成及品质分析

为探究陕西关中地区小麦HMW-GS亚基与品质性状间的关系,采用SDS-PAGE法对57份陕西关中地区小麦品种（系）HMW-GS亚基组成及相关品质性状进行了分析。结果表明,供试品种（系）中共检测出7种HMW-GS亚基类型和8种HMW-GS亚基组合;Glu-A1位点上有3种亚基类型,分别为1、2^*和Null,以1亚基为主（78.95%）;Glu-B1位点上检测到7+8（61.40%）与7+9（38.60%）两个类型;Glu-D1位点上检测到5+10（70.18%）和2+12（29.82%）两个类型。3个HMW-GS基因位点编码亚基共组成8种亚基组合,品质得分6～10分,其中1/7+8/5+10组合品质得分10分,出现频率最高。就HMW-GS不同位点对品质性状效应进行分析发现,Glu-D1位点对b^*值、形成时间、稳定时间、弱化度和粉质质量指数的影响达到极显著水平（P＜0.01）;对面团流变学特性的影响,Glu-D1>Glu-B1。不同类型亚基对小麦品质的效应存在差异,7+8亚基对蛋白质含量、湿面筋含量和容重具有正效应,7+9和5+10亚基对形成时间和稳定时间的影响显著高于其他亚基（P＜0.05）;携带1/7+8/5+10亚基组合小麦的蛋白质、湿面筋含量和容重最高;携带1/7+9/5+10亚基组合具有较高面粉L^*值和面团流变学特性指标值。     

利用HPCE构建小麦LMW-GS标准图谱初探

为给不同小麦品种低分子量谷蛋白亚基（LMW-GS）的鉴定、品质预测提供快速、准确的方法,以黄淮麦区14个普通小麦品种为材料,首先利用SDS-PAGE和分子标记确定LMW-GS组成,然后采用改进的HPCE体系分离LMW-GS,最后通过控制变量法比对小麦品种间相同亚基以判断各LMW-GS亚基在图谱中对应的峰。结果表明,采用SDS-PAGE和分子标记相结合的方法可以更加准确地鉴定小麦LMW-GS;利用HPCE体系获得的小麦LMW-GS图谱具有很高的重复性,重复试验所得小麦LMW-GS图谱中各个峰迁移时间的相对标准偏差均在0.30%以下;通过控制变量法所建立的小麦LMW-GS图谱可以实现Glu-A3a、Glu-A3c、Glu-A3d、Glu-B3a、Glu-B3d、Glu-B3h的快速鉴定。     

甘肃冬小麦品种(系)面粉品质性状相关基因分析

为了解甘肃省近20年育成的106份冬小麦品种(系)中加工品质性状相关基因分布情况,用22个分子标记对供试材料的HMW-GS、LMW-GS、面粉色泽及籽粒硬度等品质性状相关基因进行了分析。结果发现,供试品种(系)的HMW-GS相关基因中,在Glu-A1位点检测到34份品种(系)含有AxNull,频率为32.08%;在Glu-B1位点检测到Bx7+By8和Bx14+By15共2种基因组合,分别占17.92%和25.47%;在Glu-D1位点检测到11份品种(系)含有Dx5+Dy10,占10.38%。对LMW-GS鉴定结果显示,29份品种(系)含Glu-A3d基因,分布频率为27.36%。HMW-GS和LMW-GS亚基组合中,含有4个、3个和2个位点优质亚基基因组合的品种(系)分别占0.94%、8.49%和3.77%。对面粉色泽相关基因Ppo-A1、Ppo-D1、Psy-A1、Lox-B1和TaPod-A1位点的检测发现,优异等位变异占比分别为39.62%、50.94%、31.13%、30.19%和38.68%。对籽粒硬度相关基因检测发现,在Pina、Pinb和Pinb-2等位变异位点的检测...     

Comparative analyses of LMW glutenin alleles in bread wheat using allele-specific PCR and SDS-PAGE

One hundred and eighty-two bread wheat cultivars developed in India were characterized for low molecular weight (LMW) glutenins using SDS-PAGE and allele-specific polymerase chain reaction (PCR) to assess allelic diversity encoded by Glu-3 loci, as well as their utility for correctly identifying different alleles. SDS-PAGE indicated Glu-A3c is present in 64.6% of the cultivars, Glu-A3b in 13.8%, Glu-A3d in 12.7% and Glu-A3e/f in 8.8%. Seven types of alleles were present at the Glu-B3 locus: Glu-B3b (29.3%), Glu-B3g (27.0%), Glu-B3h (13.8%), Glu-B3i (16.1%), Glu-B3j (12.1%), Glu-B3c (0.6%) and Glu-B3d (1.1%). SDS-PAGE found three types of Glu-D3 alleles: Glu-D3a (30.2%), Glu-D3b (67.1%) and Glu-D3c (2.7%). However, PCR found two different alleles in cultivars classified as carrying Glu-D3a and three alleles in those identified as carrying Glu-D3b cultivars, indicating a more complex nature of the Glu-D3 locus. In conclusion, the data found greater consistency between the SDS-PAGE and PCR amplification patterns of alleles such as Glu-A3c, Glu-A3d, Glu-B3g, Glu-B3h and Glu-B3i, and less consistency between those same patterns in the Glu-A3b, Glu-A3e/f and Glu-B3b alleles. More studies are needed in order to achieve unambiguous identification of the Glu-3 alleles and thereby allow their greater utility in germplasm evaluation and breeding.     

Effects of allelic variation of HMW-GS and LMW-GS on mixograph properties and Chinese noodle and steamed bread qualities in a set of Aroona near-isogenic wheat lines

High-molecular-weight glutenin (HMW-GS) and low-molecular-weight glutenin (LMW-GS) subunits play an important role in determining wheat quality. To clarify the contribution of each subunit/allele to processing quality, 25 near-isogenic lines with different HMW-GS and LMW-GS compositions grown at two locations during the 2010 cropping season were used to investigate the effects of allelic variation on milling parameters, mixograph properties, raw white Chinese noodle (RWCN) and northern style Chinese steamed bread (NSCSB) qualities. The results showed that Glu-B1 and Glu-B3 made a large contribution to determining mixograph properties and processing quality, respectively. Subunit pairs 17 + 18 and 5 + 10, and alleles Glu-A3b, Glu-A3d, Glu-B3g and Glu-D3f made significant contributions to mixograph properties and no significant difference was detected on most parameters of RWCN and NSCSB for the allelic variation of HMW-GS and LMW-GS. The allelic interactions among glutenin loci had significant effects on wheat quality. The line with 1, 17 + 18, 2 + 12, Glu-A3c, Glu-B3b, Glu-D3c associated with superior mixograph properties, the line with 1, 7 + 9, 2 + 12, Glu-A3c, Glu-B3d, Glu-D3c had superior viscoelasticity of RWCN, and the line with 1, 7 + 9, 2 + 12, Glu-A3e, Glu-B3b, Glu-D3c had the highest total score of NSCSB. These results provide useful information for genetic improvement of the qualities of traditional Chinese wheat products.     

New B low Mr glutenin subunit alleles at the Glu-A3, Glu-B2 and Glu-B3 loci and their relationship with gluten strength in durum wheat

The B low M_r subunits of glutenin of the F₂ generation from three durum wheat crosses were analysed. Three new alleles were found at three different loci: Glu-A3i coding for 5+20 subunits, Glu-B2c coding for subunit 12* and Glu-B3l coding for 1+3+13*+16 subunits. The genetic distances between Glu-A3-Gli-A1, Glu-B2-Gli-B1, Glu-B3-Glu-B2 and Glu-B3-Gli-B1 were calculated. The effects of the allelic variation at the Glu-A3, Glu-B2 and Glu-B3 on protein content and gluten strength, as measured by the SDS-sedimentation test, were determined using F₄ lines from the three crosses. All the new alleles affected significantly gluten strength. The presence of Glu-A3i had a negative influence on SDSS values compared with the allele a. For Glu-B2 and Glu-B3 the data obtained enable the effects of the alleles on SDSS volume to be ranked: a=b>c for Glu-B2 and a>b>l for Glu-B3. The results also shown that the allelic variants at Glu-B3 had a much greater effect on gluten strength than the variants at Glu-A3 or Glu-B2 loci. A high percentage of variation in sedimentation volume was explained by the prolamins (52 and 70%).     

中国小麦微核心种质 Glu-A3位点等位变异的分布

低分子量麦谷蛋白亚基在面包和面条食品加工过程中起着十分重要的作用。为了便于对含有LMW-GS优良基因的亲本筛选,选取来源于不同麦区包括地方品种和育成品种在内的208份核心种质为供试材料,用特异PCR方法检测Glu-A3位点LMW-GS基因的等位变异。结果表明,Glu-A3d出现频率(26.4%)明显高于其他等位类型,在地方品种和育成品种中的分布频率分别为26.7%和26.0%;分布频率从大到小依次为Glu-A3d>Glu-A3c>Glu-A3a>Glu-A3b>Glu-A3e>Glu-A3g>Glu-A3f;在来源于冬春兼播麦区的育成品种中未检测出Glu-A3e和Glu-A3f。对面筋强度贡献较大的Glu-A3b在地方品种和育成品种中的分布频率分别为10.7%和18.2%,说明我国小麦总体品质水平有了较大的提升。     

Definition of the low molecular weight glutenin subunit gene family members in a set of standard bread wheat (Triticum aestivum L.) varieties

Low-molecular-weight glutenin subunits (LMW-GS) are a class of seed storage proteins that play a major role in the determination of the viscoelastic properties of wheat dough. The LMW-GSs are encoded by multi-gene families at the Glu-A3, Glu-B3 and Glu-D3 loci, with more than 15 genes present in most bread wheat varieties. However, the genic profile associated with different alleles has not been clearly defined. Here, the LMW-GSs in a set of standard varieties were analyzed using molecular markers. In most cases, each Glu-3 allele was represented by a specific haplotype; however, some alleles were undistinguishable. The Glu-A3e and Glu-A3g alleles showed an identical marker haplotype, as did the alleles Glu-B3c and Glu-B3d, and Glu-B3f and Glu-B3ab. In contrast, two haplotypes among varieties designated Glu-D3c were differentiated. The marker profiles present at the Glu-D3 locus exhibited less variation compared to the genes at the Glu-A3 and Glu-B3 loci. Results show the potential of the LMW-GS gene marker system in the characterization of the LMW-GS alleles present in specific bread wheat varieties, and its reconciliation with protein-based nomenclature. This approach will advance the understanding of the contribution of each of the LMW-GS gene alleles in the control of the end-use quality.