基于QTL定位的蓖麻株高性状遗传解析

用YC2(高杆)×YF1(矮杆)和YC1(高杆)×YF1(矮杆)组合衍生的2个F₂代群体, 对蓖麻株高性状进行相关、回归和QTL定位分析。结果表明, 株高与主穗位高、主茎节长和主茎茎粗之间显著正相关, 但与主茎节数不相关;主穗位高与主茎节数、主茎节长和主茎茎粗之间显著正相关;主茎节数与主茎节长之间显著负相关。利用QTLNetwork 2.0软件在YC2×YF1的F₂群体中检测到株高、主穗位高、主茎节数、主茎节长和主茎茎粗的5、4、6、3和2个QTL, 分别解释了45.9%、45.3%、66.1%、55.4%和12.6%的总变异。在YC1×YF1的F₂群体中检测到3、4、5、1和2个上述5性状的QTL, 分别解释了26.0%、25.5%、35.4%、37.4%和7.6%的总变异。证明QTL间的“一因多效”和连锁是株高、主穗位高和主茎节长之间高度相关的遗传基础, 加性效应是株高、主穗位高和主茎节长的主要遗传组分, 互作效应是主茎节数和主茎茎粗的主要遗传组分。建议育种上将主穗位高和主茎节长作为株高早期选择和预测的间接指标,并将多节数和短节间作为高产育种的主攻方向。     

玉米株高QTL定位研究进展

株高作为玉米的重要农艺性状,对产量、耐肥性、抗倒伏影响显著。随着分子生物学的发展,针对玉米株高性状开展了大量研究工作。总结玉米株高相关的QTL定位和基因克隆研究进展,并采用元分析技术对187个信息完整的玉米株高QTL定位结果进行整合分析,获得10个一致性QTL,并在一致性QTL置信区间内发掘可能参与玉米株高调控的候选基因。     

玉米穗行数主效位点qKRN5.04精细定位与遗传效应解析

穗行数是影响玉米产量的重要因素之一,其遗传机制解析和关键基因精细定位对开展分子育种具有重要的意义。本研究以穗行数仅有4行的"四路糯系选"和多穗行自交系"农531"(18~22行)为亲本,构建了高代回交群体和次级定位群体(四路糯选系为供体亲本,农531为轮回亲本)。通过对不同类型试验群体的多环境表型鉴定和基因型鉴定,利用完备区间作图法(ICIM)进行穗行数主效QTL定位分析,将穗行数主效位点q KRN5.04定位到第5染色体136.3~140.0 Mb的区间之内;遗传效应分析发现,该位点在不同环境条件下最大可解释的表型变异为21.76%,效应值为0.80~1.76行。通过次级分离群体重组事件分析可将其进一步定位到~300 kb区间内。本研究结果不仅为分子标记辅助选择提供了实用的In Del标记,而且为玉米穗行数主效位点q KRN5.04的图位克隆和候选基因挖掘奠定了重要的基础。     

大豆株高QTL的定位与整合分析

株高是影响大豆产量的主要性状之一,本研究利用Charleston×东农594重组自交系构建的SSR遗传图谱,采用WinQTLCartographer Ver.2.5软件的CIM和MIM分析方法对2006-2008年连续3年的大豆株高数据进行QTL定位,检测到了15个控制株高的QTLs,分别位于LGB1、LGD1a和LGG等。另外,利用BioMercator2.1的映射功能将国内外常用的大豆图谱上的株高QTLs通过公共标记映射整合到大豆公共遗传连锁图谱soymap2上,将搜集到78个株高QTLs和本研究得到QTLs进行整合分析,最终得到12个大豆株高的通用QTL,分别位于LGB1、LGC2、LGD1a、LGF、LGG、LGK和LGM,其置信区间最小可达到0.24cM,为今后对大豆株高QTL精细定位,提供有利指导。     

玉米籽粒突变体dek101的表型分析和精细定位

籽粒作为玉米储藏器官,其发育程度和物质储存直接影响玉米的产量和品质。本研究在玉米双单倍体系选育过程中发现可稳定遗传的籽粒缺陷突变体,命名为defective kernel 101 (dek101)。该突变体籽粒皱缩,粒重显著降低,胚致死,胚乳发育缺陷,不能成苗。在授粉后12 d, dek101开始出现明显的发育异常,授粉后21 d籽粒鲜重、干重、体积不再增加。扫描电镜观察发现,与野生型相比, dek101淀粉粒显著变小。遗传分析证实该突变性状受隐性单基因控制。利用441个F2单株和1648个F3单株,将该基因定位在1号染色体的标记IDP2182和IDP4600之间,物理区间约300 kb,共有5个预测基因。这些结果为挖掘与玉米籽粒发育有关的功能基因,解析籽粒发育机制奠定了基础。     

基于SNP标记的玉米株高及穗位高QTL定位

为进一步弄清玉米株高和穗位高的遗传机理,为育种生产提供服务,本研究以K22×CI7、K22×Dan3402个F₂群体为作图群体,利用覆盖玉米10条染色体的SNP标记构建了2个连锁图谱。并将这2个F₂群体衍生的分别含237和218个家系的F_2:3群体用于田间性状的鉴定。用复合区间作图模型对2个群体的株高、穗位高表型进行QTL定位分析,结果显示,在武汉和南宁两种环境条件下共定位到21个株高QTL和27个穗位高QTL;单个QTL表型变异贡献率的变幅为4.9%~17.9%;株高和穗位高QTL的作用方式以加性和部分显性为主;第7染色体上可能存在控制株高和穗位高的主效QTL。     

基于多重相关RIL群体的玉米株高和穗位高QTL定位

株高和穗位高是玉米育种中的重要农艺性状。本研究利用我国玉米育种中骨干亲本黄早四与来自不同杂种优势群的其他11个骨干自交系组配11个RIL群体,开展基于单环境、联合环境的QTL分析,分别检测到269个和176个QTL。通过区段整合,检测到21个株高主效QTL及15个穗位高主效QTL,这些QTL分布在第1、第2、第3、第6、第7、第8、第9、第10染色体上。相对于共同亲本黄早四而言,部分QTL在不同RIL群体中的效应方向一致,来自共同亲本黄早四的等位基因在不同群体中能够稳定地表达。同时,还分别定位到在多环境下稳定表达的5个株高、4个穗位高“环境钝感QTL”。此外,进一步鉴定出5个重要的株高和穗位高QTL富集区段(bin 1.01-1.02,1.08-1.11,3.05,8.03-8.05和9.07),这些区段均包含多个株高和穗位高相关QTL,如bin3.05位点包含7个QTL,bin8.03-8.05位点分别包含9个QTL,且这些QTL至少在3个不同环境中能够被检测到,这些区域对QTL的精细定位和克隆有重要参考价值。     

玉米耐深播主效QTL qMES20-10的精细定位及差异表达基因分析

干旱是影响玉米(ZeamaysL.)产量最主要的环境因素之一,具有耐深播特性的玉米种质材料能够吸收土壤深层水分,具有较强的耐旱性,因此研究玉米耐深播性状的遗传机制具有重要的理论和应用价值。本实验室前期已利用耐深播玉米自交系3681-4与普通自交系X178构建的F_2:3群体,在玉米10号染色体上定位到了一个耐深播主效QTLqMES20-10。本研究在此基础上,以X178为轮回亲本,结合前景选择和背景选择,构建了BC₃F_3:4家系,对qMES20-10迚行了确证;幵迚一步利用分子标记辅助选择构建了高代回交群体,将其精细定位于133.3～136.0Mb的区间之内。同时,利用从BC₃F_3:4家系中筛选出的两个近等基因系,迚行差异表达基因分析,发现差异表达基因主要参与了化学性应激反应、氧化还原反应和对氧化胁迫的应激反应。本研究结果为迚一步兊隆耐深播主效QTL qMES20-10奠定了基础。     

玉米株型相关性状的QTL定位

玉米株高、穗位高和雄穗分枝数是影响玉米抗倒伏性、耐密性、植株透光率及生产潜力的重要株型性状。因此,本研究以自交系T32和黄C为亲本组配了F₂和F_2:3群体,利用完备区间作图法对株高、穗位高和雄穗分枝数进行QTL检测和效应值分析。结果表明,F_2:3家系在三个环境中共检测到10个QTL位点,单一环境下单个QTL的表型贡献率介于5.84%~11.03%之间。其中,株高受部分加性效应(A)、显性效应(D)、部分显性效应(PD)和超显性效应(OD)的调控;穗位高受到部分显性效应(PD)、显性效应(D)和超显性效应(OD)的调控;雄穗分枝数受到加性效应(A)、部分显性效应(PD)和超显性效应(OD)的调控。两个环境条件下调控株高和穗位高表达的QTL,分别位于Bin3.06(bnlg1350~phi102228)和Bin4.05~Bin4.06(umc2391~umc2283)同时调控株高和穗位高。三个环境条件下调控穗位高和雄穗分枝数表达的QTL,分别位于Bin8.05(umc1121~bnlg1782)调控穗位高、Bin8.07(bnlg1065~bnlg1823)调控雄穗分枝数。通过在不同环境条件下稳定检测到的株高、穗位高和雄穗分枝数QTL位点,以期为玉米相关性状的遗传研究、精细定位及基因克隆提供有益参考。     

氮胁迫与非胁迫条件下玉米不同时期株高的动态QTL定位

以玉米杂交种农大108的203个F_2:3家系为材料,在施氮（N+）和不施氮（N－）2种条件下对拔节期到灌浆期的株高变化进行了动态QTL分析。结果表明,N胁迫条件对亲本许178影响较小,而对亲本黄C的影响较大,F_2:3群体在不同时期的株高均值在2种施肥水平下没有显著差异,但变异范围存在一定的差异。利用包含199个SSR标记的遗传连锁图谱与复合区间作图法,在N－条件下,拔节期、小喇叭口期、大喇叭口期、灌浆期分别定位1、1、2和2个非条件QTL,可分别解释各时期株高表型变异的8.42%、13.86%、24.33%和22.66%;在N＋条件下,相应时期分别定位1、1、2和4个非条件QTL,可分别解释各时期株高表型变异的8.10%、12.92%、21.30%和44.41%。在N－条件下,拔节期至喇叭口期、开花期至灌浆期分别定位了1和5个条件QTL,可分别解释该时期株高动态变异的9.14%和50.98%;在N＋条件下,相应时期分别定位1和4个条件QTL,可分别解释该时期株高动态变异的13.33%和44.47%。这些非条件QTL和条件QTL多数表现以显性和部分显性为主。     

Agronomic Performance and Nutrient Concentration of Maize (Zea mays L.) as Influenced by Nitrogen Fertilization and Plant Density

A field experiment was conducted at Samaru, Nigeria to study the influence of nitrogen fertilization and plant density on the agronomic performance and nutrient concentration of maize ( Zea mays L.). The treatments were factorial combinations of five nitrogen fertilization rates (0, 50, 100, 150 and 200 kg N/ha) and three plant density levels (25000, 50000 and 75000 plants/ha).
Nitrogen fertilization up to 150 kg N/ha enhanced grain and stover yields and increased kernel number and weight up to 100 kg N/ha. Nitrogen supply also increased maize ear length. Increased N fertilization rates increased concentrations of N, K and Mg but had no effect on P and Ca concentrations. Higher grain yield was closely associated with higher N concentration in ear leaf; with 0.1 % change in N concentration causing 177 kg/ha change in grain yield. Increased plant density increased stover yield up to 50 or 75 thousand plants/ha but depressed kernel number and weight and ear length.     

玉米花期性状的全基因组关联分析

花期性状是玉米的重要性状,与熟期、散粉结实率和产量关系密切,对玉米品种选育至关重要。为探究玉米花期性状的遗传基础,本研究以248份遗传多样性丰富的玉米自交系作为关联群体,通过2017年和2018年在河北保定和辛集的田间试验调查抽雄期、散粉期、吐丝期和散粉吐丝间隔期4个花期相关性状,利用分布于全基因组的83057个SNP标记进行关联分析。结果表明,4个花期相关性状的基因型、年份、地点、基因型与地点的互作、基因型与年份的互作均达到极显著水平;抽雄期、散粉期、吐丝期的遗传率分别为71.77%、71.27%、73.93%,并且两两性状间呈极显著正相关,散粉吐丝间隔期遗传率为62.50%,仅与吐丝期呈极显著正相关;4个花期性状共检测到18个SNPs-性状关联(共涉及16个SNP位点),单个位点的表型贡献率范围为5.46%~28.36%,仅1个位点在不同性状中检测到;筛选到81个候选基因,其中36个在GO分析中具有功能注释。潜在候选基因GRMZM5G877647编码early flowering 4蛋白,参与光周期的调节;GRMZM2G173630编码类赤霉素受体蛋白参与植物激素信号转导;GRMZM2G001139、GRMZM2G375707编码与花器官建成的MADS转录因子。这些潜在候选基因为解析玉米花期性状遗传基础和分子辅助选择育种提供参考。     

Genotypic Variation for Cold Tolerance among Twelve Maize (Zea mays L.) Populations

The objectives of this study were (1) to ascertain the genetic differences for cold-tolerance traits in a series of diallel crosses among 12 maize populations grown in field experiments, and (2) to compare, in controlled environment rooms, the modification of various metabolic parameters of two sets of four F1 variety crosses which, according to the field experiments, differed largely in seedling early vigour (cold-tolerant [Ct] vs cold-sensitive [Cs] Fl sets). Under field conditions, cold-tolerance adaptability, as monitored by shoot dry matter accumulation, appeared genetically controlled; moreover, considerable differences existed among genotypes. Field data suggested that shoot dry weight was a good indicator of plant adaptability to periods of unfavorable cool conditions. The growth-chamber experiments showed that shoot dry weights of the two sets of hybrids (Ct vs Cs), were more uniform at the highest temperature regimes than under suboptimal temperatures. Moreover, the laboratory study indicated that the interval of time of attain a specific stage of development provided a meaningful and useful criterion for differentiating the capacity of maize plants to grow at low temperatures. Although a clear association between a particular metabolite and the capacity of plants to grow at low temperatures was not observed, it was of interest to note that the total N concentration in the shoot was significantly higher in the Ct plants compared to the Cs ones.     

四川地方玉米种质的SSR聚类分析

利用SSR分子标记方法研究28个玉米自交系的遗传变异。分析四川地方玉米种质的遗传基础,并进行SSR聚类分析,探讨四川地方玉米种质与国内主要杂种优势群的关系。结果表明：大部分四川地方玉米种质均可被划分到常见的几大杂种优势群中去,少数地方玉米自交系可形成单独的类群,四川地方玉米种质具有广泛的遗传基础;SSRs能较真     

渍涝胁迫对玉米生理生化的影响研究进展

渍涝胁迫是玉米生产中重要的非生物逆境之一,对玉米的生长发育造成危害,严重制约了玉米产量的提升。因此回顾了人们针对渍涝胁迫对玉米生理生化的影响及其适应机制的研究,介绍了人们从栽培耕作和遗传育种两个角度提高玉米抗渍涝能力的研究现状,并展望了未来玉米抗渍涝胁迫的重点研究方向。     

Effect of Low Night Temperatures on Photosynthetic Activity of the Maize Seedlings (Zea mays L.)

Night chilling (5 °C) subsequently lowered photosynthetic intensity in the leaves of maize seedlings at 20 °C through an increase in leaf diffusive resistance brought on by lower tissue water content in morning hours. A more significant increase in leaf diffusion resistance was observed when soil temperature was lowered than in the case of lower air temperature.
The unfavorable effect of soil and air cooling temperature on photosynthesis was limited by air saturated with water vapour. However, as a result of lowering the night temperature from 5 °C to 1 °C, the efficiency of the protective influence of higher atmospheric humidity was decreased. This demonstrates that the participation of factors unrelated to plant water status in inhibiting photosynthesis increases with lower night temperatures.
An additional reason for inhibited photosynthesis following cool nights was a decrease in chlorophyll accumulation, below 50 μg per 1 cm² of leaf area.     

影响玉米花药培养效率的因素研究

对影响玉米花粉胚诱导的因素进行了研究。结果表明 :花药接种前对雄穗进行 5℃低温预处理 15～ 2 1d效果较好 ;接种后高温 (33℃ )连续处理花药 ,胚出现早、质量好且效率高 ;活性炭 (0 5 g/L)加入培养基中能显著地提高胚诱导效率。此外 ,还对基因型间差异进行了比较分析     

The Influence of Plant Water Stress on Net Photosynthesis and Leaf Area of Two Maize (Zea mays L.) Cultivars

The effect of plant water stress on net photosynthesis and leaf growth were investigated in order to determine to what extent leaf water potential during vegetative growth and silking affects maize development.
Two commercial maize hybrids grown in pots in a glasshouse were subjected to leaf water potentials of -1300 and -1700 kPa during the eighth leaf stage and during silking to -1700 and -2300 kPa to previously unstressed, moderately and severely stressed plants. The effect of stress on inhibiting CO₂ uptake rates and leaf areas, as well as the recovery after alleviating stress, were compared to that of unstressed plants.
No substantial differences in CO₂ uptake rates were found between medium and long seasoned cultivars. The CO₂ uptake rates per unit leaf area decreased to negative values under both moderate and severe stress conditions during both growth stages. During silking, the recovery of CO₂ uptake rate was much lower than during the eight leaf stage. Leaf area decreased proportionally with increased stress but did not recover after alleviating stress on plants stressed during both the eighth leaf and silking stages.