小麦幼苗耐热性的QTL定位分析

以小麦DH群体(‘旱选10号’ב鲁麦14’)为材料,在高温(热胁迫)及常温(对照)两种条件下考察小麦幼苗的根干重、苗干重、幼苗生物量、叶片叶绿素含量、叶绿素荧光参数及其耐热指数,并应用基于混合线性模型的复合区间作图法分析幼苗性状及其耐热指数QTL的数量、染色体分布及表达情况,以及QTL与环境的互作效应。结果显示:(1)亲本‘旱选10号’的耐热性明显优于‘鲁麦14’,且杂交后代的耐热性出现超亲分离。(2)控制幼苗耐热相关性状的QTL位点在染色体2D、6B、3A、4A、5A和7A上分布较多,而控制幼苗性状耐热指数的QTL在染色体6A、6B、3A、2D、5A和7A上分布较多,QTL位点在染色体上的分布有区域化的趋势。(3)控制幼苗性状的单个加性QTL和上位性QTL解释的表型变异分别平均为2.48%和2.65%;而控制耐热指数的单个加性QTL和上位性QTL解释的表型变异分别平均为8.84%和1.98%。(4)在热胁迫和对照条件下共检测到与幼苗性状及其耐热指数有关的加性效应QTL 13个和上位性效应QTL 28对,分布在除4D和6D以外的19条染色体上。研究表明,控制幼苗性状的QTL以上位性效应为主,而其耐热指数的QTL以加性效应为主。

Mapping QTLs for Seedling Traits and Heat Tolerance Indices in Common Wheat

A doubled haploid(DH) population with 150 lines,derived from a cross between two Chinese common wheat varieties ’Hanxuan 10’ and ’Lumai 14’ was used as the plant material to mapping quantitative trait loci(QTL) for seedling heat tolerance.The seedling traits,including root dry weight,shoot dry weight,seedling biomass,chlorophyll content,chlorophyll fluorescence parameters and their heat tolerance index(HTI) were measured under heat stress and normal temperature condition,respectively.The QTLs and QTL×environment interactions for these traits were detected using mixed-model-based composite interval mapping method.The results showed that the female parent ’Hanxuan 10’ was more tolerant to heat than the male parent ’Lumai 14’ at seedling stage,and the DHLs exhibited transgressive segregations.The most QTLs for seedling traits located on chromosomes 2D,6B,3A,4A,5A and 7A,and that for HTIs located on 6A,6B,3A,2D,5A and 7A.The distribution of QTLs for seedling traits and their HTIs on chromosomes exhibit a trend of regionalization.The average phenotypic variance explained by single additive QTL and single epistatic QTL were 2.48% and 2.65%,and that for HTIs were 8.84% and 1.98%,respectively.A total of 13 additive and 28 pairs of epistatic QTL related to seedling traits or their HTI were located on all chromosomes except 4D and 6D under two temperature conditions.The genetic effect of the QTLs for seedling traits mainly was epistatic effect and for HTIs mainly additive effect.