基于玉米导入系群体7个农艺性状的QTL定位

QTL mapping of seven agronomic traits in maize based on the introgression lines

对玉米导入系群体7个农艺性状进行QTL定位,从分子水平研究不同环境条件下控制玉米产量性状的遗传基础,为玉米育种工作提供了理论基础.选用玉米自交系PHB1M为轮回亲本,性状互补的四-287自交系为供体亲本,通过杂交、四代回交及二代自交,并结合分子标记辅助选择方法构建了208个导入系为作图群体;利用70对SSR引物和64对SRAP引物进行多态性扩增,获得了793个多态性位点;采用JoinMap4.0软件进行连锁图谱构建,得到了长度为1917.2 cM、涵盖10个连锁群的连锁图谱,分别在和林县与呼和浩特市两个环境下进行株高、穗位高、叶片数、穗长、穗粗、穗行数及百粒重7个农艺性状的表型鉴定;利用Map QTL4.0软件中MQM作图法对试验群体的7个农艺性状进行QTL定位,两地共检测到100个QTL位点, 23个株高、16个穗位高、22个叶片数、10个穗长、16个穗粗、4个穗行数和9个百粒重QTL.其中,控制5个性状的8个QTL在两个环境中同时被检测到,特别是株高和穗位高的3个QTL表达稳定性较高,为基因克隆以及标记辅助育种提供理论支撑.

Maize （Zea mays L.） is an important crop with great nutrition, fodder and energy values. The yield of maize is dependent on the integration and coordination of a lot of agronomic traits, such as plant height, ear length, grain weight per spike and others, which are controlled by micro-effects of multiple genes. The objective of this study was to identify genes related to agronomic traits in maize inbred line PHB1M and to investigate the correlation between those genes and yield-related traits. An introgression line was constructed using tetra-287 as a donor to improve the backbone maize in- bred lines and create new breeding resources. The progenies were grown and evaluated in both Helin and Hohhot, Inner Mongolia of China. With 70 pairs of SSR and 64 pairs of SRAP primers, the constructed introgression materials were genotyped. As a result, a total of 793 polymorphic loci were obtained locating 10 linkage groups. A linkage map was then constructed with a length of 1917.2 cM. By using MQM mapping method, a total of 100 QTLs were identified in both locations, which distributed on 9 linkage groups except the 10th linkage group. Fifty QTLs were detected in single environment, with LOD values ranged from 3.20 to 9.12, and contribution rates ranged from 2.2% to 35.2%. Among the 100 QTLs, 23 for plant height, 16 for ears height, 22 for number of leaves, 10 for ear length, 16 for shafts diameter, 4 for ear rows, and 9 for 100-grain weights were identified; Eight genes controlling 5 traits were consistently expressed from plant of both locations, including 2 QTLs controlling plant height （qPH1-5 and qPH2-6, qPH1-6 and qPH2-7）, 1 for ear height （qEP1-2 and qEP2-1）, 1 for leaf number（qLNl-lO and qLN2-4）, 2 for ear length （qEL1-2 and qEL2-1, qEL1-4 and qEL2-4）, and 2 for shafts diameter（qSD1-3 and qSD2-2, qSD1-8 and qSD2-5）. Three QTLs expressed stably for plant height and ear height, and 14 enriched QTL regions were found on 6 linkage groups. This research provided theoretical support for gene cloning and marker-assisted maize breeding.