Screening for grain dormancy in segregating generations of dormant x non-dormant crosses in white-grained wheat (Triticum aestivum L.)
Screening for grain dormancy in segregating generations of dormant x non-dormant crosses in white-grained wheat (Triticum aestivum L.)
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DOI：
10.1007/s10681-009-0028-z
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发表时间：
2010-03-01
期刊：
影响因子：
1.9
通讯作者：
Banks, Phillip M.
中科院分区：
文献类型：
--
作者：
Hickey, Lee T.;Dieters, Mark J.;Banks, Phillip M.
小麦（Triticum aestivum L.）是一个重大问题。将控制籽粒休眠的基因渗入白粒面包小麦是提高对小穗病抗性的一种手段。本研究以7个休眠（含SW 95 -50213和AUS 1408）×非休眠杂交组合为材料，研究了早分离世代对籽粒休眠性选择的有效性。每一代（F（1）-F（4））在具有延长的光周期（即连续光）的温控温室中生长。F（2）和F（3）世代进行选择。在14天的时间内测试500个收获成熟的谷粒的发芽，并保留100个最休眠的谷粒并生长以在每个杂交中产生下一代。通过分析F（2）、F（3）和F（4）代中至50%发芽的时间（G（50））来评估对选择的响应。此外，两个SSR标记（barc 170和ginseng 2279）侧翼的一个已知的数量性状基因座（QTL）的谷物休眠性的标记类频率的变化进行了评估，在DNA中的F（2）植物选择早期发芽（非休眠）和晚发芽（休眠）的表型极端在每个杂交。在F（2）和F（3）代中选择籽粒休眠有效地恢复了所有7个杂交组合的休眠表型，即F（4）代与休眠亲本没有显著差异。此外，基于单个F（2）谷粒的选择改变了4A休眠QTL的标记类别频率;在大多数情况下，消除了非休眠等位基因纯合的标记类别。这种筛选方法的应用将使育种者更好地选择种子休眠，并可能导致新品种的开发提供有效的抗小穗病在不久的将来。
Pre-harvest sprouting (PHS) in wheat (Triticum aestivum L.) is a significant problem. Introgression of genes controlling grain dormancy into white-grained bread wheat is one means of improving resistance to PHS. In this study seven dormant (containing the SW95-50213 and AUS1408 sources) x non-dormant crosses were produced to investigate the effectiveness of selection for grain dormancy in early segregating generations. Each generation (F(1)-F(4)) was grown in a temperature controlled glasshouse with an extended photoperiod (i.e. continuous light). F(2) and F(3) generations were subject to selection. Five hundred harvest-ripe grains were tested for germination over a 14 day period, and the 100 most dormant grains were retained and grown-on to produce the next generation within each cross. The response to selection was assessed through analysis of the time to 50% germination (G(50)) in the F(2), F(3) and F(4) generations. In addition, changes in marker class frequencies for two SSR markers (barc170 and gpw2279) flanking a known quantitative trait locus (QTL) for grain dormancy on chromosome 4A were assessed in DNA from F(2) plants selected from early germinating (non-dormant) and late germinating (dormant) phenotypic extremes within each cross. Selection for grain dormancy in the F(2) and F(3) generations effectively recovered the dormant phenotype in all seven crosses, i.e. the F(4) generation was not significantly different from the dormant parent. Further, selection based on individual F(2) grains changed marker class frequencies for the 4A dormancy QTL; in most cases eliminating the marker class homozygous for the non-dormant alleles. Application of this screening method will enable breeders to better select for grain dormancy and may lead to development of new cultivars offering effective resistance to PHS in the near future.