基因型、地点及其互作对内蒙古小麦主要品质性状的影响

选用来自我国春播麦区高、中、低3种筋力类型的9个品种, 于2003和2004年分别种植在内蒙古6个代表性地点, 研究了不同品种在年份和地点间籽粒硬度、蛋白质含量、和面仪参数和淀粉糊化特性等主要品质性状的变化规律。结果表明, 所测品质性状受基因型和地点效应的影响均达极显著水平, 除籽粒蛋白质含量外, 其他品质性状受基因型和地点互作效应的影响达显著或极显著水平。强筋类品种的蛋白质含量、灰分含量、沉降值、和面时间、耐揉性和峰值黏度均较高, 出粉率和稀澥值中等。中筋类品种出粉率、和面时间和耐揉性较高, 灰分含量、峰值黏度和稀澥值较低。弱筋类品种的灰分含量、峰值黏度和稀澥值较高, 籽粒硬度、蛋白质含量、出粉率、沉降值、和面时间、耐揉性低。所有品种品质性状在地点间存在较大差异, 乌海市灰分含量、和面时间和耐揉性高, 籽粒硬度、沉降值、峰值黏度和稀澥值较低。杭锦后旗出粉率高, 蛋白含量和沉降值较低, 其他性状表现中等。呼和浩特市籽粒硬度、蛋白含量、面粉灰分、沉降值、和面时间和耐揉性高, 出粉率、峰值黏度和稀澥值低。赤峰市多数性状表现中等。通辽市籽粒硬度、蛋白质含量、峰值黏度、稀澥值和耐揉性较高, 其他性状表现中等。额尔古纳市蛋白含量和沉降值较高, 和面时间和耐揉性低。初步认为强筋和中筋类品种较适于种植在呼和浩特市与乌海市, 不适于种植在额尔古纳市; 2个弱筋类品种在6个地点均不太适宜种植。     

Milling quality and protein properties of autumn-sown Chinese wheats evaluated through multi-location trials

Eight milling quality and protein properties of autumn-sown Chinese wheats were investigated using 59 cultivars and advanced lines grown in 14 locations in China from 1995 to 1998. Wide ranges of variability for all traits were observed across genotypes and locations. Genotype, location, year, and their interactions all significantly influenced most of the quality parameters. Kernel hardness, Zeleny sedimentation value, and mixograph development time were predominantly influenced by the effects of genotype. Genotype, location and genotype × location interaction were all important sources of variation for thousand kernel weight, test weight, protein content, and falling number, whereas genotype × location interaction had the largest effect on flour yield. Most of the genotypes were characterized by weak gluten strength with Zeleny sedimentation values less than 40 ml and mixograph development time shorter than 3 min. Eight groups of genotypes were recognized based on the average quality performance, grain hardness and gluten strength were the two parameters that determined the grouping, with contributions from protein content. Genotypes such as Zhongyou 16 and Annong 8903 displayed good milling quality, high grain hardness, protein content and strong gluten strength with high sedimentation value and long mixograph development time. Genotypes such as Lumai 15 and Yumai 18 were characterized by low grain hardness, protein content and weak gluten strength. Genotypes such as Yannong 15 and Chuanmai 24 were characterized by strong gluten strength with high sedimentation value and long mixograph development time, but low grain hardness and protein content lower than 12.3%. Genotypes such as Jingdong 6 and Xi’an 8 had weak gluten strength, but with high grain hardness and protein content higher than 12.2%. Five groups of locations were identified, and protein content and gluten strength were the two parameters that determined the grouping. Beijing, Shijiazhuang, Nanyang, Zhumadian and Nanjing produced wheats with medium to strong gluten strength and medium protein content, although there was still a large variation for most of the traits investigated between the locations. Wheat produced in Yantai was characterized by strong gluten strength, but with low protein content. Jinan, Anyang and Linfen locations produced wheats with medium to weak gluten strength and medium to high protein content. Wheats produced in Yangling, Zhenzhou, and Chengdu were characterized by weak gluten strength with medium to low protein content, whereas wheats produced in Xuzhou and Wuhan were characterized by weak gluten strength with low protein content. Industrial grain quality could be substantially improved through integrating knowledge of geographic genotype distribution with key location variables that affected end-use quality.     

稻田套播和氮素对中筋小麦产量和品质的调节效应

采用稻田套播与传统条播两种栽培方式系统比较的方法,研究不同氮肥运筹下稻田套播方式对中筋小麦扬麦10号籽粒产量和品质的调节效应。结果表明：稻田套播方式对中筋小麦籽粒产量和品质影响显著。与传统条播方式相比,在同一氮肥运筹下套播方式中筋小麦除籽粒总淀粉及其组分含量显著高于条播方式外,籽粒产量、蛋白质含量、蛋白质产量、磨粉品质和面粉品质以及淀粉糊化特性的主要指标低于传统条播,且差异显著。稻田套播方式不利于中筋小麦扬麦10号优质的形成,在江苏淮南地区中筋专用小麦采用稻田套播方式宜适当增加施氮量且追氮适度后移。     

SDS不溶性谷蛋白大聚体含量与和面仪参数的关系

选用品质差异较大的108份主栽品种和高代品系, 测定其谷蛋白聚合体总量(双缩脲法)和贮藏蛋白组分含量及比例(凝胶色谱法, SE-HPLC), 并分析了它们与蛋白质含量、沉降值以及和面仪参数等早代选择参数的相关性。结果表明, 参试材料品质特性和贮藏蛋白组分含量的变异范围都较大。和面仪峰值时间变异范围为1.12~7.19 min, 变幅达6.07 min; 醇溶蛋白总量和SDS可溶性谷蛋白聚合体(EPP)变幅较小, 而SDS不溶性谷蛋白大聚体(UPP)的变幅最大。硬度、蛋白质含量和沉降值与和面峰值时间的相关系数较低(r=0.24~0.49)。醇溶蛋白总量与和面仪参数相关不显著, 而与谷蛋白总量的比值(Gli/Glu)与和面仪参数呈显著负相关(r= –0.52~ –0.61, P＜0.001), 且不受蛋白质含量的影响。SDS不溶性谷蛋白大聚体百分含量(%UPP)与和面仪参数的相关性最高, 相关系数为0.70~0.85(P＜0.001)。SE-HPLC法样品用量少, 自动化程度高, 且%UPP和Gli/Glu为相对值, 与和面仪参数呈高度相关, 可作为面筋强度早代选择的有效指标。     

Wheat quality traits and quality parameters of cooked dry white Chinese noodles

Dry white Chinese noodle (DWCN) is widely consumed in China, and genetic improvement of DWCN quality has become a major objective for Chinese wheat breeding programs. One hundred and four bread wheat cultivars and advanced lines, including 88from major Chinese wheat-producing areas, were sown in two locations for two years. Their DWCN quality, as evaluated by trained panelists, was studied to determine the relationship between wheat quality parameters and DWCN quality attributes. In general, the cultivars and advanced lines used in this study are characterized with acceptable protein content, but accompanied with weak-medium gluten strength and poor extensibility, and substantial variation is observed for all grain and DWCN quality characters. On average, Australia and USA wheat performed better DWCN quality than Chinese wheats. Simple correlation analysis indicated that both grain hardness and Farinograph water absorption were negatively associated with cooked DWCN color, appearance, smoothness, and taste. Flour whiteness and RVA peak viscosity was positively associated with all DWCN parameters, and their correlation coefficients (r) with DWCN score are 0.34 and 0.41, respectively. Their positive contributions to DWCN quality were mostly through improved color, appearance, smoothness, and taste. Farinograph mixing tolerance index (MTI) and softening were negatively associated with all DWCN quality parameters, and their correlation coefficients with DWCN score are –0.50 and–0.54, respectively. Further analysis indicated that association between protein content, Zeleny sedimentation value, Farinograph stability, and Extensograph extensibility, and DWCN score fit quadratic regression model significantly, with R² 0.12, 0.32, 0.22, and 0.20, respectively. The associations between Zeleny sedimentation value and DWCN's appearance and taste also fit quadratic regression model significantly. This suggests that to certain extent, increased protein content and gluten quality contribute positively to DWCN quality, mostly by improving palatability, elasticity, and stickiness. High flour whiteness, medium protein content, medium to strong gluten strength and good extensibility, and high starch peak viscosity are desirable for DWCN quality. Genetic improvement for flour whiteness, protein quality and starch paste viscosity would increase the DWCN quality of Chinese bread wheat cultivars. This revised version was published online in July 2006 with corrections to the Cover Date.     

普通小麦面筋强度早代选择研究

以优质强筋小麦品种中优9507为母本,与安农91168、高优503、冀5099、晋麦45和鲁麦5号5个筋力不同的品种配制杂交组合,用亲本、F₁、F₂和F_2:3家系研究了SDS沉降值与和面时间的分布,分析了沉降值的遗传力和选择响应。结果表明,组合间F₂、F_2:3沉降值及F_{2:3相似文献}   

冬小麦高、低分子量麦谷蛋白亚基形成时间和积累强度及其与沉降值的关系

采用6个不同品质类型冬小麦品种研究高、低分子量麦谷蛋白亚基形成时间和积累强度及其与沉降值的关系。结果表明, 在籽粒形成过程中,各品种的高分子量谷蛋白亚基（HMW-GS）开始形成时间及形成速度不同,低分子量谷蛋白亚基（LMW-GS）B区在花后10 d基本形成;随着籽粒发育,HMW-GS和LMW-GS的类型和积累量都逐渐增多。强筋小麦     

强筋小麦磨粉各出粉点的面粉品质特性研究

采用布勒实验磨制粉,测定6个强筋小麦品种不同出粉点面粉的品质特性。结果表明,不同出粉点面粉的品质特性具有明显差异及变化规律。三道心磨粉的灰分含量、蛋白质含量、面糊色泽a*值和b*值、破损淀粉含量、面团形成时间和吸水率随出粉点后移均呈升高或增加趋势;而湿面筋含量、面糊色泽L*值、面团稳定时间、延伸性和最大抗延阻力随出粉点后移而降低。三道皮磨粉的蛋白质含量、湿面筋含量、破损淀粉含量、面团吸水率、稳定时间、拉伸面积、延伸性随出粉点后移呈上升趋势;而面团拉伸参数和面包烘焙品质均高于心磨粉和统粉。不同出粉点的蛋白质与湿面筋含量呈极显著正相关(r=0.81**);灰分含量与面糊色泽的L*值呈极显著负相关(r=－0.89**);破损淀粉含量与吸水率呈极显著正相关(r=0.86**)。研究表明,通过对各出粉点取舍及混配,能够克服我国强筋小麦某些指标缺陷,以满足面包专用粉各项指标要求。     

Suitability of Chinese wheat cultivars for production of northern style Chinese steamed bread

Fifty-six bread wheat cultivars and advanced lines from major Chinese wheat growing regions and 10 Australian cultivars were grown in Anyang located in Yellow and Huai Valleys and Chengdu located in Yangtze region. The genotypes were examined for their suitability to produce northern style Chinese steamed bread (CSB) and used to investigate the association between wheat quality traits and performance of northern style CSB under manual and mechanized processing conditions. Anyang-sown wheat samples showed better grain quality characteristics and CSB quality than the Chengdu-sown materials. These differences were largely due to adverse climatic conditions prevailing in Chengdu that resulted in the deterioration of flour whiteness, Farinograph stability, and starch quality. Therefore, Chengdu was generally unfavorable for producing good quality wheat. However, significant variability among cultivars was observed in Chengdu, and Batavia, Dollar bird, and Tasman from Australia and Jing 411, Xiaoyan6, and Shaan 229 from China showed very good CSB quality under manual conditions, and Hartog, Batavia, Tasman, and Vulcan from Australia, and Jing 411 and Dongfeng 1from China were identified to confer good CSB quality under mechanized conditions. The wide range of CSB quality variations indicates that genetic improvement of CSB quality is possible in both environments. Protein content, gluten strength, and extensibility were positively associated with loaf volume and steamed bread elasticity. The relationship between gluten strength, extensibility, and appearance and stickiness were highly dependent on processing methods, i.e., negatively using a manual method and positively or slightly negatively using a mechanized process. Therefore, wheat quality requirement for CSB depends on CSB processing conditions. Medium protein content and medium-to-strong gluten strength with good extensibility is desirable for mechanized methods, but weak-to-medium gluten type for manual methods. High flour whiteness and RVA peak viscosity was found desirable for CSB quality regardless of the processing method used. Flour whiteness, falling number, and peak viscosity appeared to be more crucial in determining CSB quality in Chengdu, although protein content and Farinograph stability also contributed to appearance, elasticity, and stickiness. This revised version was published online in July 2006 with corrections to the Cover Date.     

江苏省优质软麦品种品质特性与饼干加工品质的关系

明确软麦品种在大田生产中的品质表现和品质育种筛选指标,对于优质生产及提高育种效率具有重要意义。选用江苏淮南麦区15份优质软麦品种(系),鉴定其高分子量麦谷蛋白亚基(HMW-GS)组成,开展3个试验点次的大田种植,分析了小麦样本的籽粒硬度、灰分含量、蛋白质含量和质量参数、粉质仪参数、揉面仪参数、溶剂保持力、贮藏蛋白组分含量参数、黏度仪参数等品质性状和饼干加工品质。结果表明,不同类型的品质参数受基因型和环境的影响不同。所有样本的蛋白质含量、湿面筋含量、稳定时间均不达国标(GB/T 17320-2013、GB/T 17893-1999),部分品种(系)的沉淀值达标,所有样本的籽粒硬度和吸水率全部达标。相关性分析表明,籽粒硬度、灰分含量和黏度仪参数与饼干加工品质无显著相关性。沉淀值、粉质仪吸水率、粉质仪稳定时间、揉面仪峰值时间、揉面仪衰落角、水溶剂保持力、碳酸钠溶剂保持力、乳酸溶剂保持力、谷蛋白/醇溶蛋白比、不溶性谷蛋白含量和不溶性谷蛋白百分含量与饼干直径呈显著(r≤–0.520)或极显著(r≤–0.652)负相关,相关系数分别为–0.657、–0.601、–0.617、–0.659、–0.676、–0.857、–0.726、–0.616、–0.546、–0.541和–0.637。多元回归方程显示,水溶剂保持力可解释饼干直径变异的73.76%,与籽粒蛋白共同可解释饼干直径变异的83.90%。在籽粒硬度和蛋白含量选择的基础上,降低面筋强度和面粉综合吸水特性是软麦育种的主要目标,水溶剂保持力、乳酸溶剂保持力和揉面仪参数是软麦育种最重要的筛选指标。     

Mixolab参数与粉质、拉伸参数及面包烘烤品质的关系

根据仪器测定的面粉品质特性预测面包烘烤品质是进行小麦品质改良的重要方法。法国肖邦公司(Chopin Technologies, France)最新推出的Mixolab分析仪可以同时测定面粉加水后恒温揉混及面团升温后蛋白质弱化和淀粉糊化特性,明确其与现有相似仪器如粉质仪和拉伸仪等的关系对小麦品质测试具有重要意义。利用 Mixolab分析仪、粉质仪、拉伸仪测定了41份高代育种品系的有关参数和面包烘烤品质,并分析了Mixolab与粉质仪和拉伸仪相关参数的关系及预测面包品质的可靠性。结果表明,可以用Mixolab的形成时间、稳定时间、面团受热后蛋白质弱化值(C2值)和到达淀粉糊化反弹值的时间(C4时间)来预测粉质仪和拉伸仪的品质参数,可解释其变异的74%~90%;可以直接用C2值预测面包体积、外观、结构和总分,决定系数分别为52%、73%、70%和68%;预测面包质地和弹性的参数不仅包含Mixolab稳定时间和C2值,还有表示淀粉糊化特性的C3时间、C4和C5值及C5温度。用Mixolab分析仪既可以了解蛋白质特性和面包烘烤品质的关系,又明确了淀粉品质对面包品质的显著影响,在品质测试中有其独特之处。Mixolab、粉质仪和拉伸仪各参数对预测小麦面包体积、内部质地结构等烘烤品质性状的贡献不同。     

Genotypic and temperature effects on wheat grain yield and quality in a hot irrigated environment

High temperature influences both grain yield and end‐use quality of wheat. The objectives of this study were to evaluate the performance of selected wheat genotypes under heat stress and to examine the effects of high temperatures during grain filling on grain yield and end‐use quality parameters. Fifteen bread wheat genotypes in 2000/2001 and 18 genotypes in 2002/2003 were evaluated under the optimum and late‐sowing conditions of the irrigated hot environment of the Gezira Research Farm, Wad Medani, Sudan. The genotypes comprised released varieties and elite lines from the Sudanese wheat improvement programme. Data collected included grain yield, grain weight and grain end‐use quality including protein content, protein composition, SDS sedimentation values (SDSS) and gluten strength as determined by mixograph analyses. High temperatures significantly decreased grain yield by decreasing grain weight. Although genotypes exhibited variation in magnitude of response, results indicated that high temperature during grain filling increased both soluble and insoluble protein contents, SDSS, mixograph peak height (MPH) and the descending slope at 2 min past peak (MDS). In contrast, mixograph peak time (MPT) and the curve width at 2 min past peak (MCW) were significantly decreased. Flour protein correlated positively with SDSS, MPH and MDS and negatively with MCW. MPT correlated negatively with MDS and positively with MCW. Results indicate that high temperature increased both soluble and insoluble protein contents, SDSS and MPH, and hence the gluten strength, but decreased flour mixing time and tolerance and hence the dough elasticity. Variation observed among genotypes suggests that grain end‐use quality could be improved under high temperature conditions utilizing the available variability; however, it might require evaluation under various growing conditions.     

Breeding durum wheat for pasta quality in Canada

Canada was the largest durum wheat (Triticum turgidum var durum) producer in 1994, and in recent years supplied over 70% of world export trade in durum. Breeding for pasta quality is, therefore, a primary objective in Canadian durum breeding programs. Control of cultivar registration and stringent grading standards ensure that durum of consistent high quality is produced for domestic and export markets. The objectives of breeding programs include: improvement of traits related to production concerns, such as grain yield, disease resistance and sprouting resistance, and those related to end-use quality, such as protein concentration and quality; milling quality factors, such as semolina yield; colour of the wheat, semolina and pasta; and cooking quality. Selection and testing for quality begins at very early generations and becomes more stringent for advanced inbred lines. Selection is practised at the F₁ or F₂, where appropriate, using monoclonal antibodies to identify desirable gamma gliadins (γ-45 ) or low molecular weight glutenin subunits (LMW 2) that have been shown to be related to end-use quality. Grain from early generation yield trials, starting at F₄, is screened for protein concentration and pigment content by Near Infrared reflectance, and for gluten strength by sodium dodecyl sulphate (SDS) sedimentation and micro-mixograph. Promising lines entered into multi-location yield trials are screened with more time-consuming procedures to fully assess suitability for pasta processing. These tests include semolina yield, ash and colour, and predictions of gluten strength such as mixograph and alveograph, and cooking quality. Candidate cultivars with quality equal to or better than the mean of the check cultivars can be proposed for registration after three years in the Durum Cooperative Test. It takes approximately 10 years from performing a cross to registrating a new cultivar. This revised version was published online in August 2006 with corrections to the Cover Date.     

QTL analysis of quality traits in the spring wheat cross RL4452 × 'AC Domain'

Wheat grain quality is a complex group of traits of tremendous importance to wheat producers, end‐users and breeders. Quantitative trait locus (QTL) analysis studied the genetics of milling, mixograph, farinograph, baking, starch and noodle colour traits in the spring wheat population RL4452/‘AC Domain’. Forty‐seven traits were measured on the population and 99 QTLs were detected over 18 chromosomes for 41 quality traits. Forty‐four of these QTLs mapped to three major QTL clusters on chromosomes 1B, 4D, and 7D. Fourteen QTLs mapped near Glu‐B1, 20 QTLs mapped near a major plant height QTL on chromosome 4D, and 10 QTLs mapped near a major time to maturity QTL on chromosome 7D. Large QTLs were detected for grain and flour protein content, farinograph absorption, mixograph parameters, and dietary fibre on chromosome 2BS. QTLs for yellow alkaline noodle colour parameter L* mapped to chromosomes 5B and 5D, while the largest QTL for the b* parameter mapped to 7AL.     

Use of the SDS-sedimentation test and SDS-polyacrylamidegel electrophoresis for screening breeder's samples of wheat for bread-making quality

Summary Gelprotein or SDS-insoluble gel-forming glutenin was isolated from wheat flour by extraction with an aqueous 1.5% SDS solution. Remarkable intervarietal differences were observed both in amount and subunit composition of these proteins.The amount of gelprotein and the SDS-sedimentation volume both proved to be good parameters for the bread-making quality of wheat cultivars. A high correlation was observed between amount of gelprotein and SDS-sedimentation volume. The amount of gelprotein was therefore tentatively assumed to be the essential basis of the SDS-sedimentation test.The subunit composition of the gelprotein was studied by SDS-PAGE after reduction of SS bonds by mercaptoethanol. It was found that the average bread-making quality of wheat cultivars and progeny of the cross Atlas 66 x Atys which possessed subunits 3 and 10, coded for by chromosome 1D, was significantly higher than that of wheat samples possessing subunit 2 and 11, their allelic counterparts.     

从产量和品质性状的变化分析北方冬麦区小麦品种抗热性

培育抗热性强的品种对应对气候变化,保障小麦稳产性具有重要意义。选用北方冬麦区53份主栽品种和苗头品系,于2008—2009年度分别种植在北京、石家庄、衡水、安阳和泰安5点,各点设正常温度和塑料棚热胁迫处理。结果表明,千粒重可作为抗热性筛选的简易指标。农大189、CA0518和京冬8号的产量和千粒重在正常和热处理环境中均较高,抗热性好;衡观33和CA0736的产量在正常和热处理环境中均较高,但千粒重均表现中等,抗热性较好;农大211、石麦15、济麦22、农大3432和山农2149在正常环境中的产量和千粒重均较高,但在热处理环境中产量和千粒重均较低,抗热性差。53份品种按和面时间和峰值曲线面积可分为强筋、中强筋、中筋、中弱筋和弱筋5大类。热处理使所有类型材料的蛋白质含量和籽粒硬度增加,峰值带高、8min带高和8min带宽降低,并降低强筋、中强筋和中筋类型材料的和面时间与峰值曲线面积,增加中弱筋和弱筋类型材料的和面时间与峰值曲线面积。     

三个不同品质类型冬小麦品种籽粒淀粉积累动态及其有关酶的活性变化

在池栽条件下，研究了3个不同品质类型冬小麦品种藁麦8901（强筋）、豫麦49（中筋）和洛麦1号（弱筋）籽粒灌浆过程中淀粉及其组分积累动态和与之有关的酶活性变化。结果表明，3个品种籽粒灌浆过程中支链淀粉的合成均与直链淀粉的合成同时进行，灌浆中后期支链淀粉的合成比直链淀粉的合成快。豫麦49籽粒中直链、支链和总淀粉积累速率均高于其它两品种。3个品种籽粒中腺苷二磷酸葡萄糖焦磷酸化酶（AGPP）、尿苷二磷酸葡萄糖焦磷酸化酶（UGPP）、可溶性淀粉合成酶（SSS）、淀粉粒结合的淀粉合成酶（GBSS）、淀粉分支酶（SBE）活性变化均呈单峰曲线。豫麦49在灌浆期上述各酶活性变化的峰值均高于其他两品种，且大部分酶类在灌浆中后期仍维持较高活性。可见，与藁麦8901和洛麦1号相比，豫麦49具有较强的淀粉合成能力。     

基因型和环境对面团流变学特性的影响研究

用揉混仪和质构仪研究了3个不同品质类型的冬小麦品种在8个不同的生长环境条件下的面团流变学特性,分析了基因型和环境对性状的影响及各性状间的相关性。结果表明：面团流变学特性受基因型（G）和环境（E）及其互作的共同作用,其中基因型方差均值＞环境方差均值＞G×E互作均值;从性状的表现看,基因型以济麦20表现最佳,环境以烟台点综合表现最好;相关分析表明,面团粘度性状与最大拉伸阻力、拉伸比、峰值时间、峰值面积和8min带宽呈显著负相关,而与延伸度呈显著正相关。最大拉伸阻力与峰值时间、峰值面积和8min带宽呈显著正相关。因此,进行品质评价时,可用质构仪测定的面团粘度特性对面团品质进行初步快速的评定。     

Genetic diversity of wheat storage proteins and bread wheat quality

To understand the genetic and biochemical basis of the bread makingquality of wheat varieties, a large experiment was carried out with a set of162 hexaploid bread wheat varieties registered in the French or EuropeanWheat Catalogue. This material was used to analyse their allelic compositionat the twelve main storage protein loci. A large genetic and biochemicaldiversity of the gluten proteins was found. Several gliadin encoding lociexhibited the highest allelic diversity whereas the lowest diversity was foundfor Glu-A1 and Glu-D3 loci encoding some high molecularweight glutenin subunits (HMW-GS) and LMW-GS respectively. Thevarieties were grown in three experimental locations in France. Qualityevaluation was carried out from material harvested in each location usingseven technological tests: grain protein content (Prot), grain hardness(GH), Zeleny sedimentation test (Zel), Pelshenke test (Pel), water solublepentosans (relative viscosity: Vr ), mixograph test (giving 11 parameters)and the alveograph test (dough strength W, tenacity P , extensibility L,swelling G, ratio P/L and the elasticity index Ie). Genetic and locationeffects as well as broad-sense heritability of each of the 22 technologicalparameters were calculated. GH, corresponding to the major Ha gene, Pel,and MtxW (mixograph parameter) had the highest heritability coefficients,alveograph parameters like W, P, the relative viscosity Vr and severalmixograph parameters had medium heritability coefficients whereas Protand L had the lowest. Variance analysis (using GLM procedure) allowed theeffect of the allelic diversity of the storage proteins, on the geneticvariations of each quality parameters, to be estimated. Glu-1 and Glu-3 loci had significant additive effects in the genetic variations of manyparameters. Gliadin alleles encoded at Gli-1 and Gli-2 were alsofound to play significant effect on several quality parameters. The majorpart of the phenotypic variation of the different quality parameters like Zel,Pel, W or mixograph peak time MPT was explained with the GH and allelesencoded at Glu-1 and Glu-3. Allelic variants encoded at Glu3and Gli-2 had similar contribution to the phenotypic variations ofquality parameters and accounted for 4% up to 21% each.     

Effects of Mediterranean climate on wheat bread-making quality

The unpredictability of the Mediterranean climate causes a large fluctuation in wheat yield and quality but offers the opportunity for the production of high quality wheats which are lacking in the European Union.

This paper describes the effects of nitrogen fertilization rate and timing on five Triticum aestivum L. cultivars differing in bread-making quality, cultivated in six representative Italian sites (years/locations). Nitrogen was applied at each location at two rates, the first corresponding to the amount estimated to maximize grain yield, the second 30% higher. Three timings of nitrogen applications were tested including a late application at the boot stage. Bread-making quality was evaluated with the Chopin alveograph and each sample was assigned to the following qualitative classes of the Italian market: Class 1, improver wheat; Class 2, for direct bread-making; Class 3, ordinary wheat.

Cultivars differed significantly in all agronomic and qualitative traits. Grain yield was highest in the northern location (7.1 t ha⁻¹) and lowest in the south of the Italian peninsula (2.61 ha⁻¹), while in Sicily abundant rains in both years enabled a yield of 6.41 ha⁻¹ to be obtained. As far as bread-making quality is concerned, the greatest proportion of grain samples belonging to Class 1 was obtained from the northern location. The year of cultivation strongly affected quality, particularly with regard to gluten tenacity, in all locations, though the quality ranking of the cultivars remained substantially stable across locations. Nitrogen applications greater than those considered optimal to maximize yield, combined with a better distribution during the life cycle, significantly improved bread-making quality.

It was concluded that high quality wheats can be obtained in a wide range of growing conditions in the Mediterranean climate. However the likelihood of genotype × environment interactions, statistically significant for both yield and quality, call for a more precise management of nitrogen fertilization in relation to the cultivars chosen and the climatic features of each site.