玉米BADH基因的克隆与序列分析

Betaine was accumulated as a nontoxic and protective osmolyte in water-dificit and salt-stressed plants. Betaine aldehyde dehydrogenase for glycine betaine synthesis is an important enzyme. The BADH gene of Maize was cloned by RT-PCR and RACE. The gene is 1 762 bp in length, including an open reading frame of 1 515 bp.Its nucleotide sequence shares 95% with the the partial cDNA of BADHI from Sorghum bicolor. Its deduced amino acid sequence contains the conserved domain sequence “VTLELGGKSP“ of ALDH, and a tripeptide SKL at its C-terminal, a signal targetting to the microbodies. The phylogenetic tree of 20 BADHs was constructed,which corresponds to the classical botanical division of plant, the BADH of maize is closest to the one of Oryza Sativa.     

Classification approaches for sorting maize (Zea mays subsp. mays) haploids using single-kernel near-infrared spectroscopy

Doubled haploids (DHs) are an important breeding tool for creating maize inbred lines. One bottleneck in the DH process is the manual separation of haploids from among the much larger pool of hybrid siblings in a haploid induction cross. Here, we demonstrate the ability of single-kernel near-infrared reflectance spectroscopy (skNIR) to identify haploid kernels. The skNIR is a high-throughput device that acquires an NIR spectrum to predict individual kernel traits. We collected skNIR data from haploid and hybrid kernels in 15 haploid induction crosses and found significant differences in multiple traits such as percent oil, seed weight, or volume, within each cross. The two kernel classes were separated by their NIR profile using Partial Least Squares Linear Discriminant Analysis (PLS-LDA). A general classification model, in which all induction crosses were used in the discrimination model, and a specific model, in which only kernels within a specific induction cross, were compared. Specific models outperformed the general model and were able to enrich a haploid selection pool to above 50% haploids. Applications for the instrument are discussed.     

玉米细胞质雄性不育材料CMS-P的胞质分类研究

采用育性恢复专效性测定、PCR分类鉴定、类质粒鉴定3种玉米不育细胞质分类方法,对本室从爆裂玉米（Zea mays everta）种质中发现的玉米细胞质雄性不育材料“CMS-P”进行了胞质分类研究,一致表明CMS-P属于S型不育胞质。这为CMS-P的有效利用提供了理论依据。卡方测验表明,S组田间育性表现恢复的各组合花粉可染率并不完全符合1∶1的分离比例,CMS-P向可育方向偏移的程度更大。花粉可染率在不同测验系、不同胞质、不同环境间都表现出较大差异,胞质与核微效基因间的互作可能是影响育性稳定性的主要因素。     

玉米雄性不育性研究Ⅷ. 对玉米YⅡ-1不育胞质线粒体DNA RFLP分析

以玉米T、S、C群及新选育的YⅡ-1不育系为材料，用这4类群不育胞质线粒体DNA，经4种限制性内切酶酶切，长距凝胶分离酶切片段获得高分辨率的清晰谱带。再以5种线粒体特异的基因片段作为探针与酶切条带杂交，结果表明：T、S、C群表现较多差异的杂交带型，持有明显的多态性，YⅡ-1型杂交带与T、S群区别明显，与C群有少量差异。     

Cytogenetic evidence for the origin of teosinte (Zea mays ssp. Mexicana)

Summary Cytogenetic evidence has shown that teosinte (Zea mays ssp. mexicana (Schrad.) Iltes) and maize (Zea mays L. ssp. mays) are conspecific. They hybridize readily and their offspring are generally fertile. Teosinte could not have originated as a byproduct of maize-Tripsacum hybridization. Such introgression gave rise to plants that are phenotypically maize or Tripsacum, depending on which parent was used as a pollen donor. Compartive morphological and genetical studies indicated that it is more probable that maize originated from a teosinte-like ancestor under domestication, than that a maize-like plant gave rise to teosinte through a series of mutations.Reseach supported financially by the Illinois Agricultural Experiment Station, and Grants GB-40136-X and BM573-01034 A02 from the National Science Foundation.     

氮素对玉米淀粉累积及相关酶活性的影响

氮素在提高玉米籽粒产量和改善品质方面起着重要的调节作用,淀粉是玉米籽粒的主要成分,其数量多寡直接影响玉米的产量.正在发育的玉米籽粒中,合成淀粉的原料来自叶片中合成的或淀粉降解产生的蔗糖,通过韧皮部长距离运输至籽粒[1].     

QTL mapping of maize (Zea mays) stay-green traits and their relationship to yield

A maize genetic linkage map derived from 115 simple sequence repeat (SSR) markers was constructed from an F₂ population. The F₂ was generated from a cross between a stay-green inbred line (Q319) and a normal inbred line (Mo17). The map resolved 10 linkage groups and spanned 1431.0 cM in length with an average genetic distance of 12.44 cM between two neighbouring loci. A total of 14 quantitative trait loci (QTL) were detected for stay-green traits at different postflowering time intervals and identified by composite interval mapping. The respective QTL contribution to phenotypic variance ranged from 5.40% to 11.49%, with trait synergistic action from Q319. Moreover, maize stay-green traits were closely correlated to grain yield. Additional QTL analyses indicated that multiple intervals of stay-green QTL overlapped with yield QTL.     

Quantitative trait loci mapping of maize (Zea mays) ear traits under low-phosphorus stress

We constructed an F_2:3 population of 180 individuals from a cross between the maize genotypes 082 (high phosphorus use efficiency) and Ye107 (low phosphorus use efficiency). We used the population to perform quantitative trait loci (QTL) mapping for eight ear traits (ear diameter [ED], ear length [EL], ear weight [EW], ear kernel weight [EKW], row number per ear [ERN], bald tip length [BTL], kernel number per row [RKN] and number of seeds per plant [NSP]) in three low-phosphorus environments. A total of 36 QTL for ear traits were detected in at least one of three single environments and were located on all maize chromosomes except for chromosome 10; the explained phenotypic variation ranged from 5.91% to 12.80%. The QTL JAqEKW5-1, JAqEL3-1, JAqEW1-1, JAqBTL1-1 and JAqNSP5-2 were identified and stably expressed in single-environment and joint-environment analyses. Some novel QTL that have not been reported previously were also detected. Most of the identified QTL had stable effects in all low-phosphorus environments, suggesting that they may be useful for molecular breeding to develop low-phosphorus tolerant maize varieties.     

玉米茎流速率及耗水量研究

摘要：本文采用植物热平衡茎流（Sap Flow System）计,对沙漠绿洲边缘沙地种植的主要农作物玉米整株茎流速率的日变化、季节变化规律及耗水量进行了测试,结果得出：玉米径流速率日变化呈现出单峰曲线峰值为14:00时为69.7303 gm/hr。玉米在全生育期的径流速率最高值出现在7月份（平均值）为68.71 gm/hr。以玉米密度为67500株/ hm2计算茎流耗水量,在生长季节中玉米茎流速率高峰时期的6、7、8三个月蒸腾所需生理用水量为6478.2 m3/hm2。5月和9月共用水160m3,全生育期需水量8878.2 m3/hm2,比同样条件下种植药用黄芪植物多用水量4678.2 m3/hm2。另外玉米茎流速率与环境因子中的光量子密度(PFD)、大气温度（Tair）、相对湿度（RH）、水汽压亏缺（VPD）等有着及其密切的相关关系,经回归分析得出了玉米与其影响因子之间的回归方程,为沙漠绿洲边缘种植农作物玉米合理用水方案确定提供了理论依据。     

玉米雄性不育性研究 Ⅷ.玉米YⅡ-1型不育胞质归群初报

从若干方面初步研究了玉米YII-1型不育细胞质与3个主要类群的不育胞质（T、C和S）间的差异。育性恢复测验表明，YII-I胞质有其独特的恢复基因，在各类自交系核背景下，其育性表现与众不同。恢复基因至少有二对，其中一对与C群不育系有别。小斑病菌测试效应，说明YII-1型不属于T群，而线粒体DNA(mt DNA)的电泳图谱说明YII-I胞     

玉米（Zea mays L.）×大刍草（Zea diploperennis L.）远缘杂交选育玉米自交系的研究

为了丰富玉米遗传变异,从1990年起,我们进行了玉米(Zea mays L.)和多年生二倍体大刍草(Zea diploperennis L.)远缘杂交的研究。经过5年8个世代的杂交、回交和自交选择,目前已获得抗逆性、抗病虫能力较强,农艺性状优良的玉米自交系14个。在测配1000个杂交组合中,所选系表现出较高的一般配合力和特殊配合力。实践证明,这是一条导入外缘种质、拓宽玉米遗传基础,进一步提高杂交种增产潜力的途径之一。     

若干玉米胚乳突变体基因效应的研究

对５个玉米单隐性胚乳突变体、３个双隐性胚乳突变体的可溶性糖（还原糖、蔗糖）、水溶性多糖、淀粉、粗蛋白、赖氨酸含量测定，并对突变体种子结构扫描电镜观察。分析了玉米胚乳突主体的基因效应及其互作效应。     

一个玉米氯离子通道基因(clc)的电子克隆及生物信息学分析

氯离子通道植物生理代谢中起着重要的角色.通过电子克隆的方法获得玉米氯离子通道的cDNA全长序列.发现该基因包括5个外显子和4个内含子,并对其表达产物进行生物信息学分析,其表达产物与拟南芥ATCLC-A,ATCLC-B具有较高的相似性.     

A QTL atlas for grain yield and its component traits in maize (Zea mays)

Grain yield and its component traits are essential targets in maize breeding. These traits are genetically complex and controlled by a large number of quantitative trait loci (QTL). The aim of this study was to compile reported QTL and major genes for grain yield and its component traits in a QTL atlas, as a valuable resource for the maize community. To this end, 1,177 QTL related to maize yield were collected from 56 studies published between 1992 and 2018. These QTL were projected to genetic map “IBM2 2008 Neighbors”, which led to the identification of 135 meta-QTL. Some genomic regions appear to be hotspots for yield-related meta-QTL, often affecting more than one of the investigated traits. Moreover, we catalogued 20 major maize loci associated with yield and identified 65 maize homologs of 21 rice yield-related genes. Interestingly, we found that a significant proportion of them are located in meta-QTL regions. Collectively, this study provides a reference for QTL fine-mapping and gene cloning, as well as for molecular marker-assisted breeding of yield-related traits in maize.     

Cover crops and interrow tillage for weed control in short season maize (Zea mays)

Weed competition can cause substantial maize (Zea mays L.) yield reductions. Interseeding maize with cover crops or a combination of interrow cultivation and interseeded cover crops are possible alternative methods of weed control. This study was conducted to examine the potential of interrow cultivation plus cover crops to reduce weed density in maize without reducing the grain yield. Field experiments were conducted in 1993 and 1994 at two sites in Québec to determine the effects of planting 12 cover crops with maize on weed control. Fall rye (Secale cereal L.), hairy vetch (Vicia villosa Roth), a mixture of red clover (Trifolium pratense L.) and ryegrass (Lolium multiflorum Lam), a mixture of white clover (Trifolium repens L.) and ryegrass, subterranean clover (Trifolium subterraneum L.), yellow sweet clover (Meliotus officinalis Lam), black medic (Medicago lupulina L.), Persian clover (Trifolium resupinatum L.), strawberry clover (Trifolium fragiferum L.), crimson clover (Trifolium incarnatum L.), alfalfa (Medicago sativa L.), and berseem clover (Trifolium alexandrinum L.) were seeded at two planting dates, 10 and 20 days after maize emergence. Interrow cultivation was carried out weekly until forage seeding, with a final cultivation being conducted just prior to cover crop seeding. Cover crop planting date did not affect maize yields or the ability of interrow tillage plus cover crops to suppress the development of weed populations. Maize yield was less affected by the interseeded cover crops under conditions of adequate rainfall. Corn planted in fields heavily infested with weeds resulted in substantial yield reductions even when rainfall was adequate. Except for 1993 at l'Assomption interrow tillage plus cover crop treatments had consistently lower weed biomass when compared to the weedy control. Most of the weed control was due to the interrow cultivation performed prior to seeding of the cover crops. The lowest weed density occurred in the herbicide treated plots. The ability of interrow tillage plus cover crops to suppress the development of weeds was affected by the level of weed infestation, the growing conditions and location. The cover crops provide additional weed control but the interrrow tillage or some herbicide application may still be necessary.     

Assessing genetic variation of maize (Zea mays) root DNA density under contrasting water supply

Optimizing root systems is one crucial point in drought tolerance breeding of plants. Introducing root-related traits to breeding programmes is time-consuming and laborious. Most of the commonly used methods are not suitable to be applied in a larger amount of plants. Here we present a study applying a DNA-based root phenotyping method (root DNA density; RDD) for phenotyping the root system of maize. Twenty-one maize inbred lines were investigated in a rain-out shelter experiment and 19 maize inbred lines in a greenhouse experiment under well-watered and drought conditions. Beside other commonly used root traits, agronomic traits of the plants were recorded and compared to RDD. Within root traits, RDD showed high significant genotypic variation and the highest repeatabilities of up to 72.4%. In contrast to most agronomic traits, repeatabilities increased under drought conditions. Values showed also good correlations between rain-out shelter and greenhouse trial, indicating the potential of this method for obtaining comparable results across different environments.     

玉米NAC转录因子片段的克隆及分析

以三叶期玉米幼苗为材料,根据NAC转录因子特有的保守结构设计特异引物,利用RT-PCR技术获得一个玉米NAC转录因子的基因片段,并对该片段进行了测序和生物信息学分析。测序分析结果表明,克隆得到的NAC转录因子基因片段为230 bp,聚类分析结果表明其属于NAC家族的NAM亚类。该片段的获得为克隆玉米NAC转录因子基因全长,进而为玉米抗逆育种奠定了基础。     

玉米衔接式单片段导入系群体的构建和评价

以生产上广泛种植的玉米杂交种豫玉22的亲本自交系87-1和综3为受体亲本,以糯质、抗病性较好的玉米自交系衡白522为供体亲本,采用回交和自交的方法,结合SSR分子标记辅助选择,分别构建了以87-1和综3为背景的衔接式玉米单片段导入系群体,并对其遗传背景、导入片段大小、数目和覆盖率等进行了评价。结果表明,87-1背景的导入系群体导入了40个供体片段,片段长度介于0.03~342.8 cM,平均长度为91.1 cM,导入片段总长为3 643.9 cM,覆盖率为48.9%;综3背景的导入系群体导入了78个供体片段,片段长度介于0.03~343.4 cM,平均长度为75.5 cM,导入片段总长为5 895.2 cM,覆盖率为79.2%。     

Genomic selection and enablers for agronomic traits in maize (Zea mays): A review

Maize is a commodity crop providing millions of people with food, feed, industrial raw material and economic opportunities. However, maize yields in Africa are relatively stagnant and low, at a mean of 1.7 t ha⁻¹ compared with the global average of 6 t ha⁻¹. The yield gap can be narrowed with accelerated and precision breeding strategies that are required to develop and deploy high-yielding and climate-resilient maize varieties. Genomic and phenotypic selections are complementary methods that offer opportunities for the speedy choice of contrasting parents and derived progenies for hybrid breeding and commercialization. Genomic selection (GS) will shorten the crop breeding cycle by identifying and tracking desirable genotypes and aid the timeous commercialization of market-preferred varieties. The technology, however, has not yet been fully embraced by most public and private breeding programmes, notably in Africa. This review aims to present the importance, current status, challenges and opportunities of GS to accelerate genetic gains for economic traits to speed up the breeding of high-yielding maize varieties. The first section summarizes genomic selection and the contemporary phenotypic selection and phenotyping platforms as a foundation for GS and trait integration in maize. This is followed by highlights on the reported genetic gains and progress through phenotypic selection and GS for grain yield and yield components. Training population development, genetic design and statistical models used in GS in maize breeding are discussed. Lastly, the review summarizes the challenges of GS, including prediction accuracy, and integrates GS with speed breeding, doubled haploid breeding and genome editing technologies to increase breeding efficiency and accelerate cultivar release. The paper will guide breeders in selection and trait introgression using GS to develop cultivars preferred by the marketplace.     

玉米种子休眠性的QTL定位

选用两个种子休眠性差异较大的普通玉米自交系R08与A318组配的F2群体共331个单株,构建了包含137个SSR标记的分子遗传连锁图谱,覆盖玉米基因组2 076.7 cM,平均图距15.2 cM。采用复合区间作图法对F_2:3家系种子休眠性数据进行分析,共检测到7个QTL,分别位于玉米第1、3、5和10染色体上。7个QTL的贡献率在2.45%~26.