小麦面团拉伸参数和吹泡参数相关性研究

小麦经粒径分选与比重分选后,不同粒径及不同容重大小的小麦籽粒拉伸参数与吹泡参数存在差异,分析两组参数的相关性,从而揭示针对不同品质等级的小麦,两套评价指标各自的特点及两者存在的深层次联系。研究结果表明:针对拉伸参数,粒径分布在2.2～2.4cm的小麦拉伸面积和拉伸阻力平均值分别为23.7cm2和108.3EU,而到粒径分布在3.0～3.2cm的小麦拉伸面积和拉伸阻力降到13cm2和64.6EU,粒径增大,拉伸面积和拉伸阻力下降;吹泡参数随着粒径的增大其变化规律不明显。2组参数对应容重的变化规律不明显。对2组参数进行相关性分析表明两者的关联度较高,但拉伸参数可以更全面地描述受雨害小麦的加工特性。     

Genetic analysis of bread-making quality in wheat and spelt

Bread‐making quality in wheat and spelt reflects the combination of several, mostly quantitatively inherited parameters. The aim was to find molecular markers linked to quantitative trait loci (QTL) for quality parameters. Zeleny sedimentation values (Zel), protein (Prot), kernel hardness (KH) and 1000‐kernel weight (TKW) of 226 F₅ recombinant inbred lines (RILs) from a cross between wheat and spelt were assessed in different environments. The dough properties of 204 RILs were assessed with an alveograph. Based on a genetic map of 187 loci, nine QTL were found for Zel and Prot, explaining 47% and 51% of the phenotypic variance, respectively. Fifty‐four per cent of the variance was explained by 10 QTL for KH and eight for TKW. For the alveograph parameters 10 QTL were found for baking strength, nine for tenacity, seven for configuration ratio, and four for elasticity index and extensibility. The phenotypic variance explained ranged from 25% to 48%. The population mean of the dough parameters was shifted towards the spelt parent. It is concluded that non‐additive effects are crucial in the expression of high bread‐making quality of wheat. The consequences for wheat and spelt breeding programmes are discussed.     

面包小麦新春9号及其配粉效果的研究

优质面包小麦新春9号和加拿大引进的面包小麦Y20、罗布林分别经德国和法国实验磨粉机制粉后进行配粉试验,测定其粉质参数、吹泡参数和面包烘焙效果,结果表明:适宜的配粉能明显改善面粉的烘焙品质,用50;新春9号与50;罗布林搭配(法国磨),其面包体积(961.3 ml)最大,面包评分较高;用60;新春9号与40; Y20搭配后(法国磨),其面包的烘焙效果最佳,与2002年试验结果一致;不同磨粉机制成粉的粉质参数、吹泡参数和面包烘焙品质存在一定的差异,但差异不显著;相关统计分析结果表明:粉质参数的稳定时间、评价值与吹泡参数的延展性、烘焙力之间存在着极显著的正相关.     

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.     

Contributions of individual and combined Glu-B1x and Glu-B1y high-molecular-weight glutenin subunits to semolina functionality and pasta quality

Durum wheat is an important food crop used primarily for pasta production. High-molecular-weight glutenin subunits (HMW-GS) encoded by the closely linked genes Glu-B1x and Glu-B1y are known for their combined effects on pasta quality, but their individual contributions and interactions remain poorly understood. In this study, we show that individual loss-of-function mutants of Glu-B1x (ΔBx6) and Glu-B1y (ΔBy8) were associated with significant reductions in gluten strength compared to the wildtype, with stronger effects in the ΔBxy double mutant. Reductions in gluten strength were reflected in reduced mixograph and alveograph parameters, gluten index, faster extrusion flow rates and increased cooking loss. Interestingly, the Glu-B1x mutation was also associated with significant increases in grain and semolina protein content, increased pasta firmness, reduced starch viscosity and increased amylose in ΔBx6 and ΔBxy. In general, the ΔBx6 mutation had stronger effects than the ΔBy8 mutation, and significant interactions between the two genes were frequent. In addition to the basic knowledge gained on the individual effects of the Bx6 and By8 subunits and their interactions, the genetic stocks developed in this study provide useful tools to study the effects of natural or synthetic HMW-GS on pasta quality parameters in a background lacking endogenous HMW-GS.