论文标题:玉米光周期反应相关性状QTL定位研究
Study on Quantitative Trait Loci Mapping Related to Photoperiod Response in Maize
论文作者
论文导师 潘光堂,论文学位 博士,论文专业 作物遗传育种
论文单位 四川农业大学,点击次数 125,论文页数 103页File Size9892K
2007-05-20论文网 http://www.lw23.com/lunwen_4176647/
Maize;; photoperiod sensitivity;; SSR;; QTL
随着玉米育种向高级阶段发展，我国目前生产所用的种质基础越来越狭窄，这已成为育种取得突破性进展的主要限制因素。热带、亚热带种质来自玉米多样性中心，具有与我国乃至美国玉米带种质不同的遗传变异，因此引进、利用和改良热带、亚热带玉米种质是拓宽我国玉米种质基础的重要途径，也成为目前玉米育种的关键环节。而热带、亚热带种质对光周期的敏感反应却大大限制了其在温带的利用。另外，培育具有光周期钝感型的玉米自交系对于西南地区扩大杂交种的推广，以及更好地利用新疆、甘肃等西北省区的优越的生态、气候、生产等条件提高制种产量、降低生产成本和获得高质量的杂交一代种，迅速扩大推广面积等也都具有十分重要的现实意义。因此，只有不断加深对玉米光周期敏感性遗传规律的认识，才能进一步提高热带亚热带玉米种质在温带的利用效率，同时有利于提高我国西南区玉米生产水平。本研究以自交系郑58(光周期不敏感型)和自交系Ya8701(光周期敏感型)为亲本配制F_2和F_(2∶3)，采用SSR分子标记技术，同时在四川雅安(代表短日照环境)和北京(代表长日照环境)两种环境下试验，开展了玉米光周期敏感相关性状的QTL定位研究，以期为热带亚热带玉米种质在温带育种中的应用提供理论和技术参考。主要研究结果如下： 1．在长日和短日两种光周期环境下，对296个F_(2∶3)家系的抽雄期、吐丝期、散粉期、散粉吐丝间隔期、株高和穗位高6个性状进行了鉴定与统计分析。结果表明：各性状在两种环境间以及家系间均存在显著差异；抽雄期、吐丝期、散粉期、株高和穗位高的光周期敏感系数与长日条件下的产量性状之间呈显著或极显著负相关关系，这些性状可作为衡量玉米光周期敏感反应的可靠指标。 2．以郑58和Ya8701为亲本配置F_2分离群体为作图群体，利用分布于10条染色体的93个共显性的SSR标记构建遗传连锁图谱，覆盖玉米基因组的1547.4cM，标记间平均间距为16.64cM。经分子标记排列顺序与位点比较，该连锁图谱与玉米基因组数据库所公布的玉米整合图谱有较高的一致性，可以用于进一步的主效QTL定位研究。 3．以复合区间作图法(LOD≥2.5)，分别对两种环境下的6个光周期相关性状以及各性状的光周期敏感系数进行QTL分析，共检测到69个QTL位点，其中短日条件下检测到25个，长日条件下检测到31个，光周期敏感系数QTL检测到13个。单一性状单一条件下的QTL为1～7个，单个QTL对表型的贡献率为2.2％～57.6％，基因的作用方式以加性和部分显性为主。检测到的QTL在染色体上分布不均匀，有成簇分布的特点，尤其是10染色体(bin10.04)上分布密集，部分位点同时作用于多个性状。 4．生育期性状定位的QTL之间有较大的一致性，而株高和穗位高QTL与生育期性状QTL之间表现相对较独立，这与前人研究有差异，原因可能是有些共同QTL位点位于本研究建立的图谱未覆盖的玉米基因组位点而未被检测到，也可能是由于上位性效应降低了某些共同QTL位点的作用，使这些QTL因作用微小而很难被检测到。 5．本研究中通过比较发现长目条件下检测到的QTL与光周期敏感系数(PRC)QTL有更大的一致性，与Moutiq等的研究一致，推断在长日条件下检测到的QTL可能更能够代表光周期敏感特性。 6．与环境互作较小的QTL包括性状ASI中检测到的与分子标记umc1087、nc005和umc1088连锁的多个主效QTL，以及抽雄期相关的与标记umc1453相连的QTL在MAS策略中可以加以利用。另外一些主效QTL的重叠区域，可以作为光周期反应的关键区域，其相应的分子标记bnlg1655、umc1586、umc2180也可以在光周期反应的分子标记辅助改良中发挥重要作用。 7．光周期的敏感性研究与光周期诱导开花转换的研究关系密切。通过与Chardon等构建的一个具有62个QTL一致区域和6个热点区域的开花相关性状综合遗传模型比较发现，本研究检测到的QTL与其中的14个区域有一致性，并且在第9和10染色体的2个区域与发现的热点区域一致。推测本研究检测到的QTL可能与osSOC1、osCCA1／LHY、osPHYC、osZTL等生物钟组成基因相关。
The recent development of Maize breeding has largely increased the difficulties to make significant accomplishments if the breeders only exploited the temperate germplasm. Both tropic and sub-tropic maize, originated from diversified center, were confirmed to have extensively variation for China and America Maize germplasm. Thus, introduction, utilization and improvement of the exotic germplasm collected from tropic and sub-tropic regions had become an important approach to enhance domestic Maize genetic diversity. However, the characteristics of photoperiod sensitivity extremely limited the utilization of tropic and sub-tropic Maize in the temperate zone. In addition, take into account the southwest maize production, the development and cultivation of photoperiod-insensitive maize inbred lines are not only importance to popularize the hybrids in this region, but also benefit for increasing the yield and quality of hybrid-seeds under the condition of northwest of China, where have predominant environment for Maize production. In the present study, the population between inbred lines Zheng58 (insensitive) and Ya8701 (sensitive) were developed and grown under two different condition, Sichuan (represent short-days) and Beijing (represent long-days), and a systematic researches on the QTL mapping of the traits associated with photoperiod response was carried out in order to provide theoretical and technological references for the application of tropic and sub-tropic Maize to the temperate Maize breeding. The main results are showed as following. 1. The major six traits tassel date, silking date, pollen date, anthesis-silking interval, plant height, ear height of 296 F_(2:3) family lines were surveyed and analyzed under two different regions. The results showed that all traits were significant different among family lines and between the long:days and short-days; photoperiod response coefficient is significant negative correlative with the yield in long-days. These traits could thus be used to measure the photoperiod sensitivity of Maize. 2. A total of 296 F_2 individuals derived from Zheng58×Ya8701 was used to construct the integrated molecular genetic map by 93 SSRs distributed on all the 10 chromosomes, which spanned the genome of about 1547.4cM with an average of 16.64cM between two markers. The present linkage map was highly consistent with other published maize linkage maps in chromosomes, and it is apparently that the SSR-based linkage can be used for QTL mapping. 3. 69 QTL represented 11 traits were detected under long-days and short-days using composite interval mapping(LOD≥2.5), among which 25 QTL were detected in short-days, 31 QTL were found in long-days, and 13 QTL were associated with photoperiod response coefficient. 1～7 QTL have been identified in each traits which were responsible for interpreting 2.2～57.6% of the phenotypic variance individually, and showed additive and partial dominant effect. The distribution of QTL was trend to cluster on some chromosome regions, especially on the 10 chromosomes, while some loci have an effect on several traits simultaneously. 4. QTL of growth stage traits have many similar map loci, while QTL of plant height and ear height have few similar map loci with QTL of growth stage traits, which was different from previous results. The reason might be interpreted that the map loci of some common QTL were on the uncovered map position of present map or epistatic gene action decreased the effects of common QTL and these minute effects QTL were difficult to be detected. 5. In present study, QTL detected under long days had more sameness as the QTL of photoperiod response coefficient (PRC), which was agree with the result of Moutiq. So we assumed the QTLs detected in long-days should more exactly represent photoperiod response. 6. The QTL with little interaction with the environment including major QTL for ASI associated with markers umc1087、nc005、umc1088 and QTL for tassel date associated with marker umc1453 could be used in the marker-assisted selection (MAS) strategy for photoperiod sensitivity. In addition, the QTL overlapped regions should be the key chromosome regions for photoperiod response. The markers bnlg1655, umc1586, umc2180 corresponding to these regions would also be efficient in the MAS strategy. 7. Research between photoperiod sensitivity and flower conversion induced by photoperiod was related closely. Through comparing with the synthetic genetic model of flowering time with 62 consensus QTL in maize yielded by Chardon, QTL detected in this study were agree with 14 of 62 consensus QTL regions. Besides, two regions on chromosome 9 and chromosome 10 coincide with the known hot-spot regions. We also presumed that the QTL detected should be associated with the genes of circadian clock complex such as osSOC1, osCCA1/LHY, osPHYC, osZTL and so on.
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