烟草品种大叶密合抗青枯病相关QTL的检测

烟草青枯病抗性遗传基础薄弱、抗源单一，使烟叶生产面临巨大风险。寻找新抗源，增加抗性基因是烟草抗青枯病育种的当务之急。大叶密合为新近发现的一个兼具品质和抗性的烟草地方品种，为了深入研究其抗性遗传基础，本研究以大叶密合(抗)×长脖黄(感)的F₂ (152个单株)为作图群体，构建包含287个SSR位点的遗传连锁图谱，全长2691.7 cM，平均图距10.23 cM。随后通过田间病圃对亲本、F₁和F₂进行抗性鉴定，并对抗青枯病数量性状位点(QTL)进行定位及遗传效应分析。结果共检测到6个QTL，位于第7、8、9、15和22连锁群，可解释的表型变异为9.2% ~ 15.0%。比较分析发现大叶密合的抗性基因不同于已发现的抗源。本研究结果为烟草青枯病新抗源的开发利用提供重要信息。 

Detection of QTL associated with tobacco bacterial wilt resistance in cultivar Dayemihe

Due to narrow genetic basis of bacterial wilt resistance in tobacco, leaf production usually face enormous risks. In order to find new resistance sources, increased resistance genes is imperative for tobacco bacterial wilt resistant breeding. Dayemihe is a cultivar with good quality and resistance to bacterial wilt. To understand the resistance inheritance basis of Dayemihe, quantitative trait loci (QTL)conferring resistance to bacterial wilt were mapped out and characterized. A genetic linkage map with 287 SSR marker loci was constructed from a tobacco population consisting of 152 F2 individuals from Dayemihe × Changbohuang cross. The linkage map spans tobacco genome 2691.7 cM with average interval of 10.23 cM between adjacent markers. The resistance of both parents, F1 and F2 was identified, and the QTLs were mapped. 6 putative QTL for resistance to bacterial wilt were found on linkage groups 7, 8, 9, 15 and 22, accounting for 9.2% to 15.7% of phenotypic variance. This analysis indicated that resistant genes of Dayemihe were different from other resistant sources.The results provided important reference for exploitation and utilization of new resistant source in tobacco.