Genome-Wide Comparative Analysis of Genetic Diversity of Regular and Specialty Maize Inbred Lines Through Genotyping by Target Sequencing (GBTS)

Specialty maize is widely used for human and animal consumption. It is therefore important to conduct a genome-wide comparison of regular and specialty maize. In the present study, a total of 20,000 SNP markers were generated using genotyping by target sequencing (GBTS) approach, of which 18,497 high-quality SNPs were used to explore the population structure and genetic diversity of both regular (163) and specialty (124) maize resources. Neighbor-joining clustering analysis classified the 287 tested maize inbred lines into three major groups, in which popcorn and other types of maize clustered into separate groups. The regular temperate maize was further divided into five heterotic subgroups, while the waxy maize and regular tropical maize were divided into two separate subgroups. However, the quality protein maize (QPM) could not be distinguished from regular tropical maize. The highest difference in allele frequency (P?<?0.05) was observed between popcorn and waxy maize (28.2%), while 26.0% SNPs between popcorn and regular tropical maize, and 25.4% SNPs between popcorn and regular temperate maize. The information generated in this study is helpful for incorporating identified genetic variation into hybrid breeding programs for specialty maize improvement and also for genome-wide association mapping in specialty maize.

     

玉米遗传转化与商业化转基因玉米开发*

玉米是世界上种植面积最大的粮食作物,为了提高玉米产量和满足人类需求,转基因育种已经成为改良玉米性状的有效手段。自1996年美国种植商业化转基因玉米以来,利用玉米遗传转化技术开发商业化转基因玉米已取得巨大成功。综述了玉米遗传转化体系优化的重要步骤,系统总结了已开发的商业化转基因玉米的种类,并对玉米遗传转化未来发展方向进行了展望。     

松嫩平原不同株型玉米品种根系分布特征比较研究

采用土柱模拟栽培法与大田试验相结合的方法,对松嫩平原不同株型玉米的根系分布特征进行了比较。结果表明,平展型玉米和紧凑型玉米根干重最大值出现的时期不同,二者根干重分别在抽丝后15d和抽丝后30d时达到最大值,成熟时紧凑型玉米根干重比平展型高12．2％,二者根系垂直分布有明显的差异,在20cm以下的根干重比率,平展型玉米在19％以下,而紧凑型玉米高于23％,紧凑型玉米的深层根量较多,在深40～100cm土层内根干重比率比平展型高42．3％,二者的根系水平分布也不同,紧凑型玉米根系水平分布较集中,在距植株0～10cm水平范围内,根系分布比率比平展型玉米高9．6％,紧凑型玉米深层根量较多,水平分布集中,耐密植,是易获得高产的重要原因之一。     

Influence of maize/lablab intercropping on lepidopterous stem borer infestation in maize

Lepidopterous stem borers seriously affect production of maize, Zea mays L., in sub-Saharan Africa. Intercropping maize with legumes such as lablab, Lablab purpurens (L.), is one of the effective systems to control stem borers. Sole culture maize and maize/lablab intercrop system of different lablab densities were planted at two locations to investigate the effects of intercrop system on incidence and severity of stem borers with particular reference to Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae). Stem borer infestation was found to be more severe in sole culture maize than maize in maize/lablab intercrop. There was a significantly negative relationship between lablab densities and maize grain yields, suggesting a possible competition for resources between the two crops. It was concluded that density of lablab and date of planting of lablab in maize/lablab intercropping have significant affects on stem borer populations and maize grain yields.     

转植酸酶基因玉米对步甲群落动态的影响

本研究以陷阱法研究转植酸酶基因玉米及其亲本玉米在整个生长季节对地表步甲类群的影响。每个玉米品系设置6块样地, 两个玉米品系交替排列, 每个样地设置2个采样点, 共设置24个样点, 整个玉米生育期取样8次。本研究共采集步甲标本8 012头, 隶属于11属23种, 其中黄斑青步甲Chlaenius micans个体数量分别占个体总数的87.54%, 为玉米田内的主要常见物种, 蠋步甲Dolichus halensis、 后斑青步甲Chlaenius posticalis和单齿蝼步甲Scarites terricola个体数量分别占除黄斑青步甲之外所有步甲个体总数的34.77%, 31.16%和6.21%, 这些物种组成当地玉米田内的常见物种。步甲物种多样性与常见物种个体数量随季节变化明显, 且转植酸酶基因玉米与其亲本玉米田内步甲物种多样性和常见物种个体数量的季节变化趋势相似度较高。重复测量方差分析（Repeated ANOVA）结果表明, 转植酸酶基因玉米对步甲物种丰富度、 物种多度、 香农威纳多样性指数和均匀度指数均没有显著影响; 转植酸酶基因玉米田内的后斑青步甲个体数量明显增加, 但其他常见物种没有显著变化。基于非度量多维度（NMDS）的群落结构分析表明转植酸酶基因玉米与亲本玉米田内的步甲群落结构非常相似。本文结果表明转植酸酶基因玉米的种植对步甲物种多样性及常见物种没有明显影响。     

大田环境下转Bt基因玉米对土壤酶活性的影响

在大田自然条件下,比较研究了转Bt基因玉米和非转基因亲本玉米在种植和秸秆分解时对土壤酶活性影响的差异。结果表明,与亲本非转基因玉米相比,在各生育期内种植转Bt玉米对土壤蛋白酶和土壤脲酶活性均没有显著影响;在喇叭口期和抽雄期,土壤蔗糖酶和土壤酸性磷酸酶活性显著提高。在秸秆还田后,两种玉米秸秆对土壤酸性磷酸酶活性的影响没有显著差异,但使用转Bt玉米秸秆的土壤蔗糖酶、土壤脲酶和土壤蛋白酶的活性则有显著提高。与亲本玉米相比,在所有观测期内,种植Bt玉米及秸秆还田对土壤酶活性的影响,在影响的幅度及趋势上随玉米生育期和土壤酶种类的不同而产生差异,但没有观测到显著不利影响;商业化Bt玉米的环境释放仍有待长期定位观测和评价。     

The effects of phytase transgenic maize on the community components and diversity of arthropods

It is important to understand the effect of phytase transgenic (PT) maize on arthropod communities in natural ecosystems. In this study, a 2-year survey of arthropod community biodiversity in fields of PT maize (0 7 8) and non-genetically modified (RA119, non-GM) maize was performed using sweep-net sampling on the stems and leaves of the maize plants. The results showed that there was no significant difference in the individual number of herbivorous, predatory, neutral and parasitic groups in PT maize and non-GM maize. The species number of herbivorous group in PT maize was significantly lower than that in non-GM maize in 2013 (p < 0.05). The proportions of different arthropod groups were almost identical in the PT maize and non-GM maize in terms of both species and individual number. Moreover, there was no significant difference in the Shannon-Weiner diversity index (H'), evenness index (J), dominance index (D), richness (S), and species abundance (N) between the two types of maize. The similarity coefficient of the arthropod community suggested that the arthropod community composition of PT maize was similar to that of non-GM maize. Furthermore, PT maize had no significant effect on the relative stability of the arthropod community. These results indicated that despite the presence of a relatively minor difference in arthropod community between the PT maize and non-GM maize, the PT maize had little effect on arthropod community biodiversity.     

Tissue localization of maize acetylcholinesterase associated with heat tolerance in plants

Our recent study reported that maize acetylcholinesterase (AChE) activity in the coleoptile node is enhanced through a post-translational modification response to heat stress and transgenic plants overexpressing maize AChE gene had an elevated heat tolerance, which strongly suggests that maize AChE plays a positive, important role in maize heat tolerance. Here we present (1) maize AChE activity in the mesocotyl also enhances during heat stress and (2) maize AChE mainly localizes in vascular bundles including endodermis and epidermis in coleoptile nodes and mesocotyls of maize seedlings.     

EMS诱变玉米突变体苗期生理生化特性研究

实验分别选取四种白色突变玉米白1、白2、白3、白4为材料,以诱变的非突变玉米为对照。分析了玉米的代谢特性和抗性。结果表明突变体的代谢及抗性没有非突变体强,但我们也发现,在四种白色突变体中,白2表现突出。白2幼苗根系活力,叶绿素含量,POD、SOD活性,脯氨酸含量均比对照高,而加MDA含量比对照低,说明在四种突变体玉米中白2苗期表现出对环境的适应能力提高,且抗性增强。     

The role of maize root size in phosphorus uptake and productivity of maize/faba bean and maize/wheat intercropping systems

Interspecific root/rhizosphere interactions affect phosphorus (P) uptake and the productivity of maize/faba bean and maize/wheat intercropping systems. The aim of these experiments was to determine whether manipulation of maize root growth could improve the productivity of the two intercropping systems. Two near isogenic maize hybrids (the larger-rooted T149 and smaller-rooted T222) were intercropped with faba bean and wheat, under conditions of high- and low-P availability. The larger-rooted T149 showed greater competitive ability than the smaller-rooted T222 in both maize/faba bean and maize/wheat intercropping systems. The higher competitive ability of T149 improved the productivity of the maize/faba bean intercropping system in P-sufficient conditions. In maize/wheat intercropping systems, root growth, shoot biomass, and P uptake of maize were inhibited by wheat, regardless of the P-supply. Compared with T222, the larger-rooted T149 suffered less in the intercropping systems. The total biomass of the maize/wheat intercropping system was higher for wheat/T149 than for wheat/T222 under low-P conditions. These data suggested that genetic improvement of maize root size could enhance maize growth and its ability to compete for P resources in maize/faba bean and maize/wheat intercropping systems. In addition, depending on the P availability, larger maize roots could increase the productivity of intercropping systems.     

转人工miRNA抗玉米粗缩病毒载体玉米的培育及其抗病能力

玉米是重要的粮食作物,水稻黑条矮缩病毒(RBSDV)是玉米粗缩病的病原,由其引起的玉米粗缩病给玉米生产造成重大损失。利用人工mi RNA构建抗病毒植物的技术已经在多种植物中被证明有效,但是在玉米中的尝试未见报道。实验根据玉米zea-mi R159a的前体序列和RBSDV基因组中编码功能蛋白的基因和基因沉默抑制子的序列信息设计引物,构建了用于沉默RBSDV编码基因和基因沉默抑制子的ami RNA(Artificial mi RNA)基因。构建p CAMBIA3301-121-ami RNA植物表达载体,利用农杆菌介导法转化玉米自交系综31(Z31)。对转基因玉米进行分子检测,选择mi RNA表达量高的纯合体株系进行自然发病实验,按0-4的分级标准调查玉米粗缩病的严重度。结果表明,转抗粗缩病毒人工mi RNA载体玉米纯合体株系的抗病表现好于野生型玉米,其中针对基因组6的S6-mi R159转基因玉米抗病情况较好。研究表明利用人工mi RNA技术构建抗病毒病玉米新品种是可行的。     

玉米遗传转化的研究进展

自从１９８８年首次获得玉米转基因完整植株以来,玉米遗传转化技术的研究取得了许多重要进展,抗虫、抗除草剂的转基因业已率先应用于玉米的商品化生产。作者对近年来玉米遗传转化技术所取得的重要进展及其在玉米品种改良中的应用前景进行了论述。     

Maize grain concentrations and above-ground shoot acquisition of micronutrients as affected by intercropping with turnip, faba bean, chickpea, and soybean

Most research on micronutrients in maize has focused on maize grown as a monocrop. The aim of this study was to determine the effects of intercropping on the concentrations of micronutrients in maize grain and their acquisition via the shoot. We conducted field experiments to investigate the effects of intercropping with turnip (Brassica campestris L.), faba bean (Vicia faba L.), chickpea (Cicer arietinum L.), and soybean (Glycine max L.) on the iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn) concentrations in the grain and their acquisition via the above-ground shoots of maize (Zea mays L.). Compared with monocropped maize grain, the grain of maize intercropped with legumes showed lower concentrations of Fe, Mn, Cu, and Zn and lower values of their corresponding harvest indexes. The micronutrient concentrations and harvest indexes in grain of maize intercropped with turnip were the same as those in monocropped maize grain. Intercropping stimulated the above-ground maize shoot acquisition of Fe, Mn, Cu and Zn, when averaged over different phosphorus (P) application rates. To our knowledge, this is the first report on the effects of intercropping on micronutrient concentrations in maize grain and on micronutrients acquisition via maize shoots (straw+grain). The maize grain Fe and Cu concentrations, but not Mn and Zn concentrations, were negatively correlated with maize grain yields. The concentrations of Fe, Mn, Cu, and Zn in maize grain were positively correlated with their corresponding harvest indexes. The decreased Fe, Mn, Cu, and Zn concentrations in grain of maize intercropped with legumes were attributed to reduced translocation of Fe, Mn, Cu, and Zn from vegetative tissues to grains. This may also be related to the delayed senescence of maize plants intercropped with legumes. We conclude that turnip/maize intercropping is beneficial to obtain high maize grain yield without decreased concentrations of Fe, Mn, Cu, and Zn in the grain. Further research is required to clarify the mechanisms underlying the changes in micronutrient concentrations in grain of intercropped maize.     

气候变暖对东北玉米低温冷害分布规律的影响

利用东北地区48个农气站1961-2010年气象资料和近20多年玉米生育期资料,建立生育阶段热量指数和冷害指数,分析气候变暖对东北玉米4个生育阶段热量及低温冷害分布格局的影响。结果表明:热量指数总体表现为明显的增加趋势;平均温度、热量指数的年代际变化特征明显,中晚、晚熟区的上升趋势均小于早、中熟区;冷害频率总体表现为明显的减小趋势;气候变暖对两个熟型区域4个生育阶段的冷害影响并不一致,早、中熟区的冷害平均频率最大值均出现在20世纪60年代,中晚、晚熟区的冷害平均频率最大值均出现在70年代,两个熟型区域的最小值均出现在21世纪初。研究结果可为未来东北地区调整玉米种植制度和生产布局,为适应气候变化和趋利避害提供科学依据。     

转EPSPS基因抗除草剂玉米CC-2对田间节肢动物多样性的影响

【背景】转基因手段已成为改良玉米品种的重要途径之一,具有诸多优点的转基因玉米越来越受到人们的青睐。转基因玉米带来巨大经济和社会效益的同时,其安全风险问题也引发人们广泛关注,因此有必要对转基因玉米进行生物多样性影响评价。【方法】采用直接观察法和陷阱法对种植转EPSPS基因抗除草剂玉米CC-2及其对应的非转基因对照郑58的田间节肢动物进行调查,分析其群落组成、群落结构及主要类群动态。【结果】转基因玉米CC-2无论是喷施除草剂还是不喷施除草剂处理,与其对应的非转基因对照郑58相比,田间节肢动物群落组成、群落结构,以及田间主要节肢动物类群动态均无显著差异。【结论与意义】初步认为转EPSPS基因抗除草剂玉米CC-2对节肢动物多样性无安全风险,为转EPSPS基因抗除草剂玉米的推广提供一定生态安全数据。     

Relationships between maize and teosinte of Mexico and Guatemala: Numerical analysis of allozyme data

Electrophoresis revealed 153 variants at 19 enzyme loci among 77 accessions of annual teosinte, 1 accession of diploid perennial teosinte, 1 accession of tetraploid perennial teosinte, and 43 accessions of maize from Mexico and Guatemala. One hundred and thirty-three (87%) variants were found within teosinte, and 95 (61%) variants were found within maize. Seventy-four (48%) variants were distributed among both teosinte and maize, whereas 58 (38%) variants were found only in teosinte and 20 (13%) variants were found only in maize. The majority of alleles were found in low frequency. A single allele predominated across maize and teosinte at 11 loci, 3 loci showed similar trends and 5 loci showed greater variability for the predominant alleles among maize and teosinte. Principal components analysis revealed little overlap between maize and teosinte, involving a minority of maize collections and Balsas teosintes. No clear evidence could be seen suggesting recent introgression between maize and teosinte. The collections of maize and teosinte were seen to represent a rich and contrasted array of germplasm.     

玉/豆和玉/薯模式下氮肥运筹对玉米氮素利用和土壤硝态氮残留的影响

过量施用氮肥造成的环境问题日益严重,氮肥合理使用已成为人们研究的热点.本文研究了西南玉米两种主要套作模式下氮肥运筹对玉米氮素利用和土壤硝态氮残留的影响.结果表明：连续分带轮作种植玉/豆模式后,玉米收获期植株中的氮素积累较玉/薯模式平均提高了6.1%,氮收获指数增加了5.4%,最终使氮肥利用效率提高4.3%,氮素同化量提高了15.1%,氮肥偏生产力提高了22.6%;玉米收获后硝态氮淋溶损失减少,60～120 cm土层中硝态氮残留玉/豆模式较玉/薯模式降低了10.3%,而0～60 cm土层中平均提高了12.9%,有利于培肥地力,两年产量平均较玉/薯模式高1249 kg·hm^-2,增产22%;增加施氮量提高了植株氮素积累,降低了氮肥利用率,显著提高了表层土壤中硝态氮的累积,60～100 cm土层中硝态氮的累积量在0～270 kg·hm^-2处理间差异不显著,继续增加施氮量会显著增加土壤硝态氮的淋溶;氮肥后移显著提高了土壤0～60 cm土层硝态氮的积累.两种模式下施氮量和底追比对玉米氮素吸收和硝态氮残留的影响结果不一致,玉/豆模式以施氮180～270 kg·hm^-2、按底肥∶拔节肥∶穗肥=3∶2∶5的施肥方式有利于提高玉米植株后期氮素积累、氮收获指数和氮肥利用效率,减少了氮肥损失,两年最高产量平均可达7757 kg·hm^-2;而玉/薯模式在180 kg·hm^-2、按底肥∶穗肥=5∶5的施肥方式下,氮素积累利用及产量均优于其他处理,两年平均产量为6572 kg·hm^-2,可实现两种模式下玉米高产、高效、安全的氮肥管理体系.
     

麦田套种玉米共生期农田生态环境特征及对夏玉米苗期生长的影响

以登海661、郑单958为试验材料,设置麦田套种和麦收后接茬直播两种不同种植方式对比试验,研究了麦田套种玉米共生期的农田生态环境特征及对玉米苗期生长的影响.结果表明： 麦田套种玉米与直播玉米相比,土壤含水量差异较小;麦田套种玉米耕层（0～5 cm）土壤的种际最高温度比直播玉米低4.8～5.2 ℃,最低温度相近,日平均温度低1.4～1.7 ℃,日变化较小,但均达到种子萌发要求;麦田套种玉米苗期冠层光照强度比直播显著减少,套种玉米地表光强为自然光强的4.4%～10.6%,光照不足是玉米苗弱、迟发的主要原因.与直播相比,套种玉米种子萌发出苗速度和干物质积累速度较慢,叶龄较小,叶片瘦长,株高较矮,玉米苗健壮度下降,单株叶面积较小且叶绿素含量较低;随共生期延长,玉米苗生长受抑制程度增加.在大田生产中,直播可促进种子萌发出苗,有利于夏玉米幼苗的生长发育,形成壮苗.     

Termite damage to maize grown in agroforestry systems, traditional fallows and monoculture on nitrogen-limited soils in eastern Zambia

Abstract 1 Termites cause significant damage to maize and other crops in southern Africa. Several studies were conducted with the objective of determining the difference in termite damage to maize in various land use systems between monoculture maize, maize grown using traditional fallows and improved fallows. 2 In an experiment conducted at four sites on noncoppicing fallows, maize planted after Tephrosia candida 02971 fallows had lower termite damage compared with fully fertilized monoculture maize. However, the termite suppression was not low enough to warrant rotation of noncoppicing fallows for termite management.. 3 In four experiments comparing termite damage to maize grown in monoculture and in coppicing fallows, fully fertilized monoculture maize had a higher percentage of lodged plants compared with maize grown in pure Leucaena leucocephala, Gliricidia sepium and Acacia anguistissima fallows or in a mixture of A. anguistissima + Sesbania sesban or Tephrosia vogelii + S. sesban. 4 More than 50–75% of the variance in maize yield was explained by preseason inorganic nitrogen and termite damage. However, termite damage to maize was not influenced by inorganic nitrogen, which represents nitrogen readily available to maize. The decomposition rate of biomass (related to lignin + polyphenol to nitrogen ratio) and water retention under fallows also appeared to influence termite damage. 5 It is concluded that maize grown in L. leucocephala, G. sepium, A. anguistissima and S. sesban fallows suffers less termite damage and produces maize yields comparable with conventionally tilled and fully fertilized monoculture maize.