【作者】 马延华；

【导师】 王庆祥； 陈绍江；

【作者基本信息】 沈阳农业大学 ， 作物学， 2013， 博士

【摘要】 玉米低温冷害是我国东北及某些省份高寒山区严重的自然灾害,也是不少国家和地区普遍性的严重灾害。冷胁迫已经成为限制东北地区玉米生产主要的非生物胁迫因素之一。选育和创造耐冷玉米种质,是减少此种危害最经济有效的途径。开展耐冷性鉴定及遗传理论研究是选育耐冷玉米品种的基础,开展玉米耐冷种质的发掘及耐冷相关性状QTL定位具有重要的现实意义。本研究以36份玉米自交系为试验材料,通过对玉米自交系低温下发芽能力、幼芽存活率、苗期若干形态学性状、生理指标的测定,综合大量指标的分析比较而筛选建立耐冷性鉴定的指标体系；利用本试验建立的玉米耐冷性鉴定体系,对来自黑龙江寒带植物资源研究中心的276份玉米自交系分别进行发芽期、芽期和苗期耐冷性评价及其相关分析；选用黑龙江省耐冷自交系甸骨11A与冷敏感自交系T935构建的DH群体为试验材料,采用P1、P2与DH群体3世代主基因+多基因联合分离分析模型来研究玉米发芽期、芽期及苗期耐冷性的遗传规律；通过构建遗传连锁图谱初步定位玉米发芽至苗期耐冷性QTL位点。旨在建立玉米发芽至苗期耐冷性的鉴定体系和量化指标；筛选耐冷玉米种质资源,为耐冷育种提供特异种质；揭示耐冷性遗传规律；并检测控制耐冷性的QTL,获得与耐冷基因紧密连锁的分子标记,为玉米耐冷分子标记辅助育种提供理论依据。主要研究结果如下：1.10℃低温与25℃常温下种子相对发芽率与田间相对出苗率极显著正相关(R=0.620),并且供试自交系间存在极显著差异,用该指标可进行玉米自交系发芽期耐冷性的鉴定；在2℃C/6d低温胁迫下,供试自交系平均存活率的标准差及变异系数均表现最大,能够比较客观地区分玉米自交系间耐冷性遗传差异,该胁迫条件可用于芽期耐冷种质的筛选；以玉米三叶一心期3℃低温处理5d的存活率作为苗期耐冷性鉴定指标是可行的。相关分析表明,幼苗总干重、苗干重、根干重、丙二醛、叶绿素、电导率、SOD、CAT等8项指标的相对值与苗期耐冷性关系非常密切,以这些指标的平均隶属函数值能够综合评价玉米自交系苗期耐冷性。同时,这些性状的选择可为育种工作者选育强耐冷玉米品种提供形态学以及生理学水平的理论基础。2.PFM32、吉4112、ZYM237、EY20、ZYM264、甸骨11A、垦自167-1等共计50份自交系表现为极强的发芽期耐冷性；T123、HR10、HB14、KLM17、ZYM249、ZYM264共计6份自交系表现为极强的芽期耐冷性；PFM32、ZYM249、HR10、吉818、龙系53、H050、意牛、扎917、宾自901共计9份自交系表现为极强的苗期耐冷性。PFM32、 ZYM264.甸骨11A、ZYM249、KLM17、T123、吉63、HR10等自交系在三个不同时期的耐冷性均较强,可作为耐冷基因源应用于耐冷育种。在低温条件下,不同地区间自交系相对发芽率、幼芽存活率、幼苗存活率平均值均以俄罗斯自交系最大,显著或极显著高于中国和法国自交系。来自俄罗斯的自交系在三个时期耐冷1级自交系所占比例也均为最高,明显高于中国和法国自交系,说明俄罗斯自交系中有较多的耐冷基因,在俄罗斯玉米种质中挖掘强耐冷种质资源的潜力较大。3.发芽期相对发芽率的遗传为2对加性-上位性主基因+多基因模型,主基因遗传率为91.57%,多基因遗传率为7.86%。芽期存活率符合3对加性-上位性主基因+多基因的混合遗传模型,主基因遗传率为95.48%,多基因遗传率为4.46%。苗期存活率符合2对隐性上位主基因+多基因的混合遗传模型,主基因遗传率为86.50%,多基因遗传率为12.91%。玉米耐冷性的遗传涉及到主基因和多基因,其主基因遗传率较高,且存在多基因的修饰。因此,改善玉米耐冷性在基于研究主基因利用的同时,也要注重多基因的积累。4.共检测到18个控制玉米生长早期耐冷性的QTL,分布在玉米的第1,2,3,4,5,6,9和10染色体上,贡献率介于3.16%到15.71%之间。控制发芽期、芽期和苗期耐冷性的QTL数目分别为5、7和6个。对发芽期、芽期和苗期在第6染色体的短臂上均检测到效应值大于10%的主效QTL,这可能是控制玉米生长早期耐冷相关性状的热点区域。在所有检测到的QTL中,只有位于第6染色体bnlg1641-bnlg1422区域内的1个QTL分别控制芽期和发芽期的耐冷性,其余QTL只能控制某单个时期的耐冷性,说明玉米不同时期的耐冷性遗传机制可能不同。更多还原

【Abstract】 Maize chilling damage cause a huge production loss in Northeast China and some provinces alpine mountains and also was a disasters for many countries and regions. Chilling stress has become a major factor limiting production of maize in Northeast abiotic stress. It is a most cost-effective way to breed and select chilling maize germplasm. It is important to identify chilling tolerance for germplasm and conduct genetic research. Moreover, it has practical significance to select chilling tolerance germplasm and conduct quantitative trait loci (QTL) mapping for chilling tolerance. In our study,36maize inbred lines were measured by germinate at low temperatures, budding survival rate, seedling morphological traits and physiological indicators to establish chilling tolerance indicator system. Based on the chilling tolerance indicator system,276maize inbred lines from Plant Resources Research Center of Heilongjiang boreal were evaluated by chilling tolerance indicator such as germination, budding and seedling. Chilling-resistant inbred Diangull and chilling intolerance inbred T935were constructed a Double haploid (DH) population for QTL mapping of chilling tolerance traits from germination to seedling. We also analyzed the data from P1, P2and DH population by a major gene polygene joint segregation analysis model to find the genetic architecture. The obeject of our study were to:(1) establish maize chilling tolerance identification systems and quantitative indicators;(2) select chilling tolerance germplasm;(3) reveal the genetic architecture of chilling tolerance;(4) QTL mapping for chilling tolerance;(5) find closely linkage markers for chilling tolerance which was benefit for maker assisted selection (MAS) to select chilling tolerance maize inbred lines. The mainly results were as follows:1. It showed significant positive correlation (R=0.620) between relative germination rate of seed germination and field relatively germination at10℃and25℃temperature. This indicator can be used maize germination identification chilling tolerance because there was significant difference among tested inbred lines. The standard deviation and coefficient of variation was largest among different inbred lines at2℃under6days, which can distinguish genetic differences for maize chilling tolerance. So this stress conditions can be used for chilling tolerance germplasm screening. It is feasible that the survival rate when maize leaf stage at3℃low temperature under5days as indicate for chilling tolerance. The maize chilling tolerance closely related with that total dry weight of seedlings, seedling dry weight, root dry weight, MDA, chlorophyll, conductivity, SOD, CAT and other eight indicators. The average value of membership function of these indicators can comprehensively evaluate maize seedling chilling tolerance. Meanwhile, the choice of these traits can provide theoretical basis on morphological and physiological level for breeders to develop strong chilling-resistant maize varieties 2. Fifty inbred lines showed strong chilling tolerance at germination stage such as PFM32, Ji4112, ZYM237. EY20. ZYM264, DiangullA, Kenzi167-1. Six inbred lines showed strong chilling resistance at budding stage such as T123, HR10, HB14, KLM17. ZYM249, ZYM264. Nine inbred lines showed strong seedling chilling tolerance such as PFM32, ZYM249, HR10, Ji818, Long53, H050, Yiniu, Zha917, Binzi901. The inbred lines such as PFM32, ZYM264, DiangullA, ZYM249, KLM17, T123, Ji63, HR10showed strong chilling tolerance at three different periods which can be used for maize breeding for chilling resistance. At low temperatures, Russian inbred lines showed largest average relative germination rate, budding survival and seedling survival rate among different regions of inbred lines, significantly higher than China and France inbred lines. The proportion of first class inbred lines among all inbred lines for Russian inbred lines was highest, significantly higher than China and France inbred lines. Russian inbred lines have more chilling tolerance genes in maize germplasm and it is effective way to develop strong chilling-resistant germplasm in Russian.3. The genetic for maize chilling tolerance genes involved in major and multiple genes whose major gene heritability is high, and there are multiple genetic modification. The trait on germination based on germination rate controlled by2genes based on additive-epistatic major genes plus multi-gene models. The heritability for major gene was91.57%and polygene was7.86%. The trait on budding survival rate controlled by3genes based on additive-epistatic major genes plus multi-gene models. The heritability for major gene was95.48%and polygene was4.46%. The trait on seedling survival rate controlled by2genes based on additive-epistatic major genes plus multi-gene models. The heritability for major gene was86.50%and polygene was12.91%. Therefore, to improve chilling tolerance in maize research, we should also pay attention to the accumulation of multiple genes in spite of utilization of major gene.4. Eighteen QTL were detected for maize chilling tolerance from germination to seedling distrubited among chromosome1,2,3,4,5,6,9,10, which explaining3.16%to15.71%phenotypic variance. The number of QTL controlling germination, budding and seedling chilling tolerance were5,7and6respectively. The phenotypic variance for QTL on chromosome6was over10%and this QTL was detected in these three periods, which may be a hotspot for early growth of maize resistant to chilling related traits. Among all the QTLs, the QTL on chromosome6between markers bnlg1641and bnlgl422was related to chilling tolerance during budding and seedling. However other QTL explained for chilling tolerance only a single period. So the genetic mechanisms may be different for different periods of chilling tolerance.更多还原