Båga Monica, Chodaparambil Sanjay V, Limin Allen E, Pecar Marin, Fowler D Brian, Chibbar Ravindra N
Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, Saskatchewan, S7N 5A8, Canada.
Funct Integr Genomics. 2007 Jan;7(1):53-68. doi: 10.1007/s10142-006-0030-7. Epub 2006 Jun 15.
Low-temperature (LT) tolerance is an important economic trait in winter wheat (Triticum aestivum L.) that determines the plants' ability to cope with below freezing temperatures. Essential elements of the LT tolerance mechanism are associated with the winter growth habit controlled by the vernalization loci (Vrn-1) on the group 5 chromosomes. To identify genomic regions, which in addition to vrn-1 determine the level of LT tolerance in hexaploid wheat, two doubled haploid (DH) mapping populations were produced using parents with winter growth habit (vrn-A1, vrn-B1, and vrn-D1) but showing different LT tolerance levels. A total of 107 DH lines were analyzed by genetic mapping to produce a consensus map of 2,873 cM. The LT tolerance levels for the Norstar (LT(50)=-20.7 degrees C) x Winter Manitou (LT(50)=-14.3 degrees C) mapping population ranged from -12.0 to -22.0 degrees C. Single marker analysis and interval mapping of phenotyped lines revealed a major quantitative trait locus (QTL) on chromosome 5A and a weaker QTL on chromosome 1D. The 5A QTL located 46 cM proximal to the vrn-A1 locus explained 40% of the LT tolerance variance. Two C-repeat Binding Factor (CBF) genes expressed during cold acclimation in Norstar were located at the peak of the 5A QTL.
耐低温是冬小麦（Triticum aestivum L.）的一项重要经济性状，它决定了植株应对冰点以下温度的能力。耐低温机制的关键要素与由5号染色体上的春化位点（Vrn-1）控制的冬性生长习性相关。为了鉴定除vrn-1外还能决定六倍体小麦耐低温水平的基因组区域，利用具有冬性生长习性（vrn-A1、vrn-B1和vrn-D1）但耐低温水平不同的亲本构建了两个双单倍体（DH）作图群体。通过遗传作图对总共107个DH系进行分析，构建了一张长度为2873 cM的整合图谱。Norstar（LT(50)= -20.7℃）×Winter Manitou（LT(50)= -14.3℃）作图群体的耐低温水平范围为-12.0至-22.0℃。对表型系进行的单标记分析和区间作图揭示了5A染色体上的一个主要数量性状位点（QTL）和1D染色体上一个较弱的QTL。位于vrn-A1位点近端46 cM处的5A QTL解释了40%的耐低温变异。在Norstar中冷驯化期间表达的两个C-重复结合因子（CBF）基因位于5A QTL的峰值处。
