玉米株型性状QTLs作图群体分析

玉米紧凑株型对于提高种植密度,增加单位面积产量,满足玉米生产发展的需求具有重要的意义。试验以株型紧凑和松散的优良玉米自交系豫82、豫87-1为亲本,组配和构建F_2∶3家系,以其作为株型性状QTLs定位与分析的作图群体。通过对株型6个相关性状,株高、穗位高、叶长、叶宽、叶夹角、叶向值在郑州、三亚两个地点的研究表明,亲本自交系在株型性状上存在显著差异,其后代F_2∶3家系间存在显著差异,各株型性状均呈连续变异、正态分布,说明所选材料适合作为QTLs定位与分析的作图群体。     

低温胁迫及恢复对玉米光合特性的影响

以玉米自交系掖478、合344、吉853为材料,在不同低温胁迫及恢复正常温度情况下比较幼苗光合作用及叶绿素荧光参数等指标的变化。结果表明,随着胁迫温度的下降和低温胁迫时间的延长,3个玉米自交系幼苗叶片初始荧光F_o呈上升趋势,F_v/F_o、F_v/F_m整体上均呈下降趋势。叶绿素荧光参数随着低温胁迫程度的加强变化较大,且相同温度下的变化幅度掖478<合344<吉853。3个玉米自交系在各温度胁迫后恢复到常温时的叶片初始荧光F_o下降,F_v/F_m、F_v/F_o整体上呈上升趋势。掖478恢复常温1～2 d后恢复到正常水平,抗冷性最强;吉853的PSⅡ系统受损较重,恢复常温3 d未达正常水平,抗冷性较弱。     

两个春小麦品系抗叶锈性遗传分析

叶锈病是我国小麦的重要病害,筛选抗病资源并进行遗传分析,对小麦抗叶锈病育种具有重要意义。本研究利用常规遗传和等位性测验方法,对8821-1-1和九三98-61297两个春小麦品系的抗叶锈性进行了遗传分析。两个品系分别与感病品种Thatcher杂交,获得的F₁植株全部抗病,F₂群体和F₃家系在苗期和成株期的抗病性测定结果经卡方测验,均分别符合3抗病∶1感病及1全抗∶2抗感分离∶1全感的分离比例;两个春小麦品系相互杂交,及其与 Lr13的载体品系Manitou杂交,其F₂全部抗病。说明8821-1-1和九三98-61297均含有一对显性抗叶锈病基因 Lr13,在苗期28 ℃下控制对小麦叶锈菌致病类型PHT/RP的抗性,在成株期控制对PHT/RP、PHT/RN和THT/TP致病类型等比混合菌种的抗性。在此基础上,本文对 Lr13的有效性进行了进一步评价。     

玉米叶片水分利用效率与叶绿素a荧光参数的关系

利用Handy PEA植物效率仪测定叶绿素a荧光参数,研究玉米自交系叶片水分利用效率(WUE)与叶绿素a荧光参数的关系。结果表明,玉米自交系叶片WUE与叶绿素a荧光参数呈极显著的正相关。其中,F_o与高水分利用效率(HWUE)玉米自交系WUE的相关系数大于低水分利用效率(LWUE)玉米自交系WUE的相关系数;最大荧光(Fm)、可变荧光(F_v)、PSⅡ原初光能转换效率(F_v/F_m)和PSⅡ潜在活性(F_v/F_o)与水分利用效率不同的玉米自交系叶片WUE的相关系数恰好相反,这是造成不同玉米自交系WUE存在差异的生理原因之一,同时也说明叶绿素a荧光参数可以作为选育HWUE玉米自交系的重要指标。     

8622×GY220 F2∶3家系植株性状的分离特征及相关分析

利用普通玉米自交系8622与高油玉米自交系GY220杂交构建的F_2∶3家系为材料,在春播环境条件下对8个植株性状进行了初步分析。结果表明：F₁各植株性状介于双亲之间或高于双亲;F_2∶3家系间各性状均存在极显著差异,并呈连续正态分布,存在明显双向超亲分离;株高与穗位高、顶高、穗上叶片数、雄穗长,穗位高与雄穗长,顶高与顶高/株高、穗上叶片数、雄穗长,穗上叶片数与雄穗分枝数间均呈显著或极显著的表型和遗传正相关;穗位高与顶高、顶高/株高、穗上叶片数间均呈显著或极显著的表型和遗传负相关。     

EMS诱变玉米自交系种质创新应用

利用0.5 mg/L EMS诱变玉米自交系K22及B73花粉，构建2 206个株系不同遗传背景的玉米突变体库，从M₂和M₃后代筛选到包括株型、叶型、叶色、育性、抗逆、表皮形态建成等表型变异的一系列突变体。具有育种应用潜能的E16、E199和W594突变材料，可供用于选育矮秆、低穗位高、耐密植抗倒伏型新品种。对调控植物表皮形态建成的E88和sep-1（smooth epidermal pavement cell lobes-1）突变体进行表皮形态、发育模式鉴定及遗传学分析，构建了F_2：3分离群体。     

玉米胚乳突变基因ae1和du1的遗传效应

利用玉米ae1和du1隐性纯和突变自交系与普通玉米自交系48-2的杂交F₁、F₂代子粒为研究材料,通过单粒法测定子粒的直链淀粉含量和重量,用于分析玉米胚乳突变基因ae1和du1的遗传效应。结果表明：F₂代中具有ae1或者du1纯和突变的子粒表皮皱缩,重量明显下降,直链淀粉含量显著提高。在ae1与du1的杂交后代中,子粒的单粒重和直链淀粉含量没有显著变化,表明ae1与du1双突变并不能导致直链淀粉含量增加。单突变的ae1和du1群体内各子粒间的直链淀粉含量和重量差异较大,说明遗传背景中存在影响直链淀粉含量的修饰基因,表明在选育高直链淀粉玉米品系时,应当重视遗传背景的选择和修饰基因的累加。采用单粒法技术对分离后代进行直链淀粉含量和重量选择,有利于积累高直链淀粉修饰基因,是选育子粒饱满、高粒重的高直链淀粉玉米自交系的有效方法。     

大麦黄花叶病抗性的遗传分析与QTL定位

大麦黄花叶病是依靠土壤中禾谷多黏菌传播的病毒病,严重影响冬大麦的产量和品质,培育和利用抗病品种是最经济有效的防治方法。本研究以抗病品种扬饲麦1号与感病品种Gairdner为亲本,以杂交F₁代经花药离体培养技术构建的DH群体为材料,对其大麦黄花叶病抗性进行两年鉴定与分析,并利用91对在亲本间多态性好的SSR(simple sequence repeat)标记构建了群体的遗传连锁图谱,采用Windows QTL IciMapping 4.0软件中的完备区间-加性模型（ICIM-ADD）对大麦黄花叶病进行QTL定位,共检测到9个与大麦黄花叶病病情指数相关的QTLs, 其中,qRYM-1Ha、 qRYM-1Hc、qRYM-2Ha 及qRYM-2Hb在两年间均被检测到,且 qRYM-2Ha在两年6个时期均被检测到,位于EBmag0793至GBM1047标记区间内,可解释的表型变异为5.61%～38.04%; qRYM-2Hb在 2015年第二、三期和2016年第一期被检测到,位于GBM1047至Bmag0749标记区间内,可解释的表型变异为11.40%～18.80%。qRYM-1Ha和 qRYM-4Ha可能是两个新的大麦黄花叶病抗性QTLs,黄花叶病抗性基因均来源于黄花叶病抗性品种扬饲麦1号。本研究为大麦黄花叶病抗性基因的发掘、精细定位、基因克隆及分子标记辅助选择育种提供了有利信息。     

玉米雄性不育性测交反应及恢复性遗传

用16个玉米自交系同C型、Y型和Y_Ⅱ型雄性不育系测交、回交,以了解不育系的恢保关系;将C型不育系测交F1中的可育株自交,同时与C型不育系回交。以分析C型不育系恢复性的遗传行为。结果表明,5003、330、白330、035-6、木6-11等5个自交系为C型不育系的恢复系,32-2、贞367、i-1等3个自交系保持C型不育系的不育性;TR3702、77-1、承10-9、5003、449、交51等6个自交系保持Y型不育系的不育性;贞367、107-1为YⅡ型不育系的恢复系,TR3702、青C₂、035-6、330、5003等5个自交系保持Y_Ⅱ型不育系的不育性。32-2对C型、承10-9对Y型、5003对Y型和YⅡ型的回交F₁全部不育,可用连续回交法转育成新不育系。C型不育系测交F₂出现可育与不育的3:1育性分离,回交一代出现1:1的育性分离,表明恢复性受一对显性基因控制。     

利用分子标记定位玉米小粒突变体mn7基因的研究

利用甲基磺酸乙酯(EMS)对玉米自交系郑 58进行诱变，获得 1个可以稳定遗传的小粒突变体mn7(miniature 7)。mn7成熟子粒表现为体积变小、子粒偏白、胚乳发育缓慢，百粒重降低 60.2%，粒长、粒宽、粒厚均极显著降低。mn7突变体的子粒在授粉后 15 d即可观察到明显小于野生型的子粒。对其自交后代和回交后代的遗传分析表明，该性状受隐性单基因控制。用mn7纯合体与自选玉米自交系 19HL3012杂交构建的包含 348个个体的 F₂分离群体，将该基因定位于玉米第 7染色体上 bin7.02区域内分子标记 umc2327和 SYM232之间 5.8 cM的范围内，距umc2327为 4.4 cM，距 SYM232为 1.4 cM。初步的生物信息学分析表明， mn7可能是 1个新基因或新等位基因。     

Quantitative trait loci mapping and meta-analysis across three generations for popping characteristics in popcorn

Popping characteristics play a determinant role in the utilization of popcorn (Zea mays L.). In this study, the RIL population with 258 recombinant inbred lines was evaluated to detect quantitative trait loci (QTLs) for three popping characteristics (PF, popping fold; PV, popping volume; PR, popping rate) under four environments. Meta-analysis was used to integrate detected QTLs across three generations (RIL, F_2:3 and BC₂F₂) derived from the same cross. All eleven QTLs were detected for three traits, on chromosomes 1, 2, 4, 6 and 10 for PF, on chromosomes 1, 4, 6, 7 and 10 for PV, and on chromosomes 1, 4, 6 and 10 for PR. Three, 1, 3, 6 and 6 QTL were detected in the same marker intervals in 4, 3, 2, 1 cases, respectively. Four QTLs at bins 1.05–1.06, 1.08–1.09 and 7.03–7.04 were commonly detected in the same or near bins in all three generations. Six and 2 QTLs showed consistency across RIL/F_2:3 or RIL/BC₂F₂ generations respectively. Nine meta-QTLs (mQTL) were detected on chromosomes 1, 4, 6, 7, 8 and 10. Except mQTL7-1, only related with PV, other mQTLs included two or three traits, reflecting pleiotropic or tightly linkaged QTLs for popping characteristics. The QTL influencing all the three popping traits at bins 1.05–1.06 were also detected in other previous researches using different populations, which could be put into use in marker assisted breeding for popping characteristics in popcorn.     

Quantitative trait loci mapping and meta-analysis across three generations for popping characteristics in popcorn

Popping characteristics play a determinant role in the utilization of popcorn (Zea mays L.). In this study, the RIL population with 258 recombinant inbred lines was evaluated to detect quantitative trait loci (QTLs) for three popping characteristics (PF, popping fold; PV, popping volume; PR, popping rate) under four environments. Meta-analysis was used to integrate detected QTLs across three generations (RIL, F_2:3 and BC₂F₂) derived from the same cross. All eleven QTLs were detected for three traits, on chromosomes 1, 2, 4, 6 and 10 for PF, on chromosomes 1, 4, 6, 7 and 10 for PV, and on chromosomes 1, 4, 6 and 10 for PR. Three, 1, 3, 6 and 6 QTL were detected in the same marker intervals in 4, 3, 2, 1 cases, respectively. Four QTLs at bins 1.05–1.06, 1.08–1.09 and 7.03–7.04 were commonly detected in the same or near bins in all three generations. Six and 2 QTLs showed consistency across RIL/F_2:3 or RIL/BC₂F₂ generations respectively. Nine meta-QTLs (mQTL) were detected on chromosomes 1, 4, 6, 7, 8 and 10. Except mQTL7-1, only related with PV, other mQTLs included two or three traits, reflecting pleiotropic or tightly linkaged QTLs for popping characteristics. The QTL influencing all the three popping traits at bins 1.05–1.06 were also detected in other previous researches using different populations, which could be put into use in marker assisted breeding for popping characteristics in popcorn.     

基于元分析的抗玉米灰斑病QTL比较定位

以玉米遗传连锁图谱IBM2 2008 Neighbors为参考图谱,整合65个抗玉米灰斑病QTL,构建QTL综合图谱。采用元分析方法优化65个QTL,获得11个"一致性"QTL区间,分别位于染色体bin区的1.05、1.06、2.03、2.07、3.02、4.05、5.03、5.05、7.02、8.07、9.03位置,其在遗传连锁图谱上对应的位置分别为442.21、528.27、228.10、478.00、74.65、311.59、169.62、302.35、252.19、422.70、257.93 cM。对两个具有较多报道和较高表型贡献的"一致性"QTL区间bin1.05和bin1.06,从MaizeGDB网站搜索得到324个基因。因抗病基因在结构上具有高度保守性,将324个基因分别与水稻和拟南芥基因组进行同源比对,在bin1.05和bin1.06内分别确定了7个和3个基因作为玉米抗灰斑病候选基因。     

Molecular Mapping of Sterility QTLs qSS-3, qSS-6a and qSS-7 as Single Mendelian Factors via NIL strategy

Hybrid sterility between Oryza glaberrima and O. sativa seriously hampers the introgression of favorable genes from each other. In order to further understand this issue, identification and isolation of hybrid sterility QTLs as single Mendelian factors are an effective strategy. A genetic map was constructed using a BC₁F₁ population derived from a cross between an O. sativa japonica cultivar and an O. glaberrima accession. Four main-effect QTLs for pollen sterility were detected in the BC₁F₁. Five BC₈F₁ advanced backcross populations were developed via successive backcrosses based on phenotype and molecular selections. The BC₈F₁ populations showed bimodal distribution for pollen fertility and could be classified into semi-sterile and fertile types, fitting single Mendilian factor inheritance ratios. Three QTLs detected in the BC₁F₁ corresponding to qSS-3, qSS-6a and qSS-7 were mapped on chromosomes 6, 3 and 7, respectively, as single Mendilian factors.     

Characterization of free amino acid QTLs in maize opaque2 recombinant inbred lines

The opaque2 (o2) mutation in maize (Zea mays L.) increases the content of free amino acids (FAA) in the endosperm. We investigated the basis of this trait by using recombinant inbred lines from a cross of Oh545o2 (high FAA) and Oh51Ao2 (low FAA) to identify quantitative trait loci (QTL) for FAA content and to determine their effect on FAA composition and protein accumulation. Mapping identified six QTLs that accounted for 71% of the phenotypic variation. Two QTLs in bins 4.01 and 7.02 are close to α-zein genes; high FAA individuals with these QTLs had reduced accumulation of α-zein 19 kDa isoforms and increased FAA abundant in α-zeins. A QTL in bin 3.03 is close to a gene encoding triose phosphate isomerase (tpi4) and a higher expression of this enzyme was found in high FAA individuals. Other differentially expressed proteins included vicilin-like globulins and the enzymes glyceraldehyde-3-phosphate dehydrogenase, enolase-2, sorbitol dehydrogenase and granule-bound starch synthase. The results suggest that the increased levels of FAA in o2 endosperm are mainly due to the reduction of storage proteins and the failure to incorporate their amino acids into other proteins, as well as the alteration of carbohydrate metabolism that may favor amino acid biosynthesis.     

玉米矮花叶病抗病基因Rscmv1的精细定位

以感病亲本Mo17为轮回亲本、抗病亲本四一为供体亲本,构建近等基因系,对抗病基因Rscmv1进行精细定位。结果表明,在自交系四一中定位了两个抗病基因Rscmv1和Rscmv2,其中Rscmv1是抗源中普遍存在的主要抗病基因。以选育的近等基因系BC4F3、BC4F4和BC4F5为定位群体,在抗病基因区域内开发了9个有多态性的BAC-SSR标记,将Rscmv1定位在BAC-SSR标记A5-1和B2-1之间,其遗传距离分别为0.3 cM和0.6 cM,2个标记之间的物理距离为1.38 Mb。     

小麦花药伸出特性的QTL分析

花药伸出特性直接影响小麦的授粉结实率和穗部真菌病害抗性,为挖掘控制小麦花药伸出特性的QTL,以半闭颖品种周8425B和开颖品种小偃81构建的包含102个株系的F_2:12RIL群体为材料,于2019和2020年各分两个播期种植于西北农林科技大学小麦试验站,以小麦花药伸出率和视觉花药伸出等级两个性状表型值对4个环境下的花药伸出特性进行表型鉴定,并利用90K芯片构建的高密度遗传连锁图谱进行QTL定位。结果共检测到8个控制花药伸出特性的QTL,分布在3A、3B、5B、6B、6D和7A染色体上,其中6B和6D染色体上各有2个QTL。 QAe.nwsuaf-3A、 QAe.nwsuaf-3B和 QAe.nwsuaf-6B位点在多个环境中均能被检测到,表型变异解释率分别为3.65%~10.48%、8.12%~26.09%和3.49%~8.93%。     

大麦品种扬农啤5号的黄花叶病抗性QTL定位

为分析大麦黄花叶病抗性基因的位置和效应,以高抗大麦品种扬农啤5号和感病大麦品种日引3号构建的253个RIL群体及亲本为材料,利用在双亲间具有多态性的108对SSR分子标记构建遗传群体连锁图谱,结合大麦黄花叶病抗性表型数据,采用QTL IciMapping 4.0软件进行大麦黄花叶病抗性QTL分析。结果表明,在大麦染色体1H、2H、5H和7H共检测到6个与大麦黄花叶病抗性相关的QTL,这6个QTL对大麦黄花叶病抗性的贡献率为4.39%～14.92%。其中,位于2H染色体的QTL qRYM-2Hb在3年9个时期均能检测到,介于标记区间GBM1309～EBmac0415,可解释5.70%～14.92%的表型变异,与已定位的 Rym16~(Hb)的位置相近,可能是 Rym16~(Hb)的等位基因;位于2H染色体的QTL qRYM-2Ha在2年3个时期均能检测到,介于标记区间EBmac0640～Bmag0744,可解释5.00%～10.88%的表型变异,可能是1个新的抗性位点;其他4个抗性QTL均仅在1年1个时期检测到,是否真实存在尚需进一步验证。同时,所有QTL的加性效应均为负值,表明定位的6个大麦黄花叶病抗性基因均来自母本扬农啤5号。     

硬粒小麦白粉病成株抗性QTL的遗传分析

小麦白粉病是世界范围内广泛流行的小麦叶部真菌病害,显著影响小麦的产量和品质。由于现有品种的白粉病抗性不断丧失,使得进一步挖掘新的白粉病抗源及抗病基因十分重要。本研究以硬粒小麦品种UC1113和Kofa构建的包含93个株系的F₈代RIL群体为材料,利用235个多态性标记构建遗传图谱,并结合白粉病成株抗性表型数据,对4个环境下的白粉病成株抗性进行QTL定位。结果表明,在RIL群体中共定位到4个与白粉病成株抗性相关的QTL,分别位于1AL、4AL（2）和5AL染色体上。其中,来自UC1113的3个QTL（ QPm.hnau-1AL 、 QPm.hnau-4AL.1 和 QPm.hnau-4AL.2 ）为新的白粉病成株抗性QTL。本研究为小麦白粉病抗性基因挖掘和抗病育种提供了重要信息。     

Identification and validation of QTLs for cold tolerance at the booting stage and other agronomic traits in a rice cross of a Japanese tolerant variety,Hananomai, and a NERICA parent,WAB56-104

In Africa, cold temperatures occur in the highlands of East and Southern Africa and in some areas of the Sahel region of West Africa leading to substantial rice yield losses. Cold tolerance (CT) at booting stage on basis of spikelet fertility after cold water irrigation was evaluated using F₂ population derived from a cross between temperate japonica, Hananomai, and tropical japonica, WAB56-104. Two Quantitative trait loci (QTLs) for CT were detected on chromosome 8 and 10 with enhanced effects on the trait coming from Hananomai and WAB56-104 allele, respectively. The QTLs explained 30% and 33% of phenotypic variation in spikelet fertility, respectively. CT was negatively correlated with panicle number (r = ?0.35, p < 0.01) and positively correlated with panicle weight (r = 0.61, p < 0.001). Selected BC₁F₄ and BC₁F₅ genotypes having homozygous alleles for both CT QTLs exhibited higher spikelet fertility under cold stress. The identified QTLs will be useful in the development of cold-tolerant varieties for production in high altitude areas through marker-assisted selection.