Ma W, Appels R, Bekes F, Larroque O, Morell M K, Gale K R
CSIRO Plant Industry, GPO Box 1600, ACT 2601, Australia.
Theor Appl Genet. 2005 Aug;111(3):410-22. doi: 10.1007/s00122-005-2001-0. Epub 2005 Jun 18.
Doubled haploid lines (n = 160) from a cross between wheat cultivars 'Cranbrook' (high dough extensibility) and 'Halberd' (low dough extensibility) were grown at three Australian locations. The parents differ at all high- and low-molecular-weight glutenin loci. Dough rheological parameters were measured using small-scale testing procedures, and quantitative trait locus (QTL) mapping procedures were carried out using an existing well-saturated genetic linkage map for this cross. Genetic parameters were estimated using three software packages: QTLCartographer, Epistat and Genstat. Results indicated that environmental factors are a major determinant of dough extensibility across the three trial sites, whereas genotypic factors are the major determinants of dough strength. Composite interval mapping analysis across the 21 linkage groups revealed that as expected, the main additive QTLs for dough rheological properties are located at the high- and low-molecular-weight glutenin loci. A new QTL on chromosome 5A for M-extensibility (a mixograph-estimated measure of extensibility) was detected. Analysis of epistatic interactions revealed that there were significant conditional epistatic interactions related with the additive effects of glutenin loci on dough rheological properties. Therefore, the additive genetic effects of glutenins on dough rheological properties are conditional upon the genetic background of the wheat line. The molecular basis of the interactions with the glutenin loci may be via proteins that modify or alter the gluten protein matrix or variations in the expression level of the glutenin genes. Reverse-phase high performance liquid chromatography analysis of the molar number of individual glutenin subunits across the population showed that certain conditional epistases resulted in increased expression of the affected glutenin. The epistatic interactions detected in this study provide a possible explanation of the variable genetic effects of some glutenins on quality attributes in different genetic backgrounds and provide essential information for the accurate prediction of glutenin related variance in marker-assisted wheat breeding.
以小麦品种“克兰布鲁克”（面团延伸性高）和“戟”（面团延伸性低）杂交产生的双单倍体系（n = 160）在澳大利亚的三个地点种植。双亲在所有高分子量和低分子量谷蛋白位点上存在差异。使用小规模测试程序测量面团流变学参数，并利用该杂交组合现有的充分饱和的遗传连锁图谱进行数量性状位点（QTL）定位分析。使用三个软件包估计遗传参数：QTLCartographer、Epistat和Genstat。结果表明，环境因素是三个试验地点面团延伸性的主要决定因素，而基因型因素是面团强度的主要决定因素。对21个连锁群进行的复合区间作图分析表明，正如预期的那样，面团流变学特性的主要加性QTL位于高分子量和低分子量谷蛋白位点。在5A染色体上检测到一个新的M-延伸性（用揉混仪估计的延伸性指标）QTL。上位性互作分析表明，存在与谷蛋白位点对面团流变学特性的加性效应相关的显著条件上位性互作。因此，谷蛋白对面团流变学特性的加性遗传效应取决于小麦品系的遗传背景。与谷蛋白位点相互作用的分子基础可能是通过修饰或改变面筋蛋白基质的蛋白质或谷蛋白基因表达水平的变化。对群体中各个谷蛋白亚基摩尔数进行的反相高效液相色谱分析表明，某些条件上位性导致受影响谷蛋白的表达增加。本研究中检测到的上位性互作可能解释了一些谷蛋白在不同遗传背景下对品质性状的可变遗传效应，并为在标记辅助小麦育种中准确预测谷蛋白相关变异提供了重要信息。
