Molecular dissection of a dormancy QTL region near the chromosome 7 (5H) L telomere in barley
Molecular dissection of a dormancy QTL region near the chromosome 7 (5H) L telomere in barley
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DOI：
10.1007/s00122-003-1281-5
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发表时间：
2003-08-01
影响因子：
5.4
通讯作者：
Ullrich, SE
中科院分区：
文献类型：
--
作者：
Gao, W;Clancy, JA;Ullrich, SE
大麦（Hordeum vulgare L.）由于种子休眠的遗传复杂性和环境效应大，在育种实践中很难对其进行调控。数量性状基因座（QTL）定位为育种者操纵数量性状基因开辟了一条途径。北美大麦基因组计划（North American Barley Genome Project）利用区间作图法和相对低分辨率的遗传图谱，将一个种子休眠性QTL SD 2定位在第7（5 H）L染色体端粒附近的8 cM区间内。SD 2具有中等休眠效应，这使其成为大麦品种培育中有希望的种子中等休眠候选基因。SD 2基因的精细定位是SD 2基因在大麦育种中有效利用的基础，也将有助于大麦休眠性的研究。产生了10种不同的Morex等值线，包括再生的Morex，其中9个线具有重复。等值线与Steptoe和Morex一起在生长室和田间环境中生长2年（2000年和2001年）。在生长室中，采用相对较低的生长温度（25 ℃白天/15 ℃夜晚）来促进种子休眠的发展。种子发芽率，在不同的收获后后成熟期测定，用于衡量种子休眠。利用基于等位线间差异的替代作图法进行精细定位，将SD 2 QTL定位在第7（5 H）染色体L端粒附近的分子标记MWG 851 D和MWG 851 B之间，间隔为0.8cM。种子发育过程中相对较低的温度（小于或等于25 ℃）促进了SD 2休眠QTL的表达。MWG 851 D-MWG 851 B区间以上的染色体区域可能在降低大麦种子后熟过程中的休眠性方面发挥作用。
Moderate seed dormancy is desirable in barley (Hordeum vulgare L.). It is difficult for breeders to manipulate seed dormancy in practical breeding programs because of complex inheritance and large environmental effects. Quantitative trait locus (QTL) mapping opens a way for breeders to manipulate quantitative trait genes. A seed dormancy QTL, SD2, was mapped previously in an 8-cM interval near the chromosome 7 (5H) L telomere from a cross of 'Steptoe' (dormant)/'Morex' (non-dormant) by the North American Barley Genome Project using an interval mapping method and a relatively low-resolution genetic map. SD2 has a moderate dormancy effect, which makes it a promising candidate gene for moderate seed dormancy in barley cultivar development. The fine mapping of SD2 is required for efficient manipulation of SD2 in breeding and would facilitate the study of dormancy in barley. Ten different Morex isolines were generated, including regenerated Morex, of which nine lines had duplicates. The isolines together with Steptoe and Morex were grown in growth room and field environments for 2 years (2000 and 2001). In the growth room, relatively low growing temperatures (25 degreesC day/15 degreesC night) were employed to promote seed dormancy development. Seed germination percentage, determined at different post-harvest after-ripening periods, was used to measure seed dormancy. Fine mapping using the substitution mapping method based on differences among isolines resolved the SD2 QTL into an 0.8-cM interval between molecular markers MWG851D and MWG851B near the chromosome 7 (5H) L telomere. Relatively low temperatures (less than or equal to25 degreesC) during seed development promoted the expression of the SD2 dormancy QTL. The chromosome region above the MWG851D-MWG851B interval might play a role in reducing barley seed dormancy during after-ripening.