6个玉米自交系配合力分析及应用评价

The 6 maize inbred lines have been tested on the paper with the design of p1×p2 uncomplete diallel crossing of NCⅡ method to study on combining ability and its genetic parameters of 9 characters.The result indieated that the lines of Zheng311,Zheng314 and Ye478 with the higher common combining ability can be directly used,the lines of Zheng312 and Zheng315 with less comprehensive character must be modified before used.The 6 combinations with higher heterosis have potentiality of increasing yield production.In maize breeding program.The 8 characters such as kernel high per plant should be selected earlier and the 1 characters such as kernel weight per plant should be selected later.     

Determination of Heterotic Groups and Heterosis Analysis of Yield Performance in indica Rice

To compare the heterosis levels among various groups of parental lines used extensively in China, identify foundational heterotic groups in parental pools and understand the relationship between genetic distance and heterosis performance, 16 parental lines with extensive genetic variation were selected from various sub-groups, and 39 hybrid combinations were generated and evaluated in Fujian and Hainan Provinces of China. The main results were as follows:(1) The 16 parental lines can be grouped into 7 sub-groups consisting of 1 maintainer sub-group and 6 restorer sub-groups;(2) Mean grain yield of the restorer lines was higher than that of the maintainer lines, and mean yield of parental lines was higher than that of the hybrid combinations;(3) The two best heterotic patterns were II-32A × G5 and II-32A × G6, moreover, the order of restorer sub-groups according to grain yield, from the highest to lowest, was G7, G6, G5, G4, G3 and G2; High specific combining ability values were observed for combinations of II-32A × G5, II-32A × G6 and Tianfeng A × G7;(4) Hybrid combinations derived from II-32A crossed with 13 restorer lines had higher yield trait values(mid-parent heterosis, better-parent heterosis, standard heterosis over check and specific combining ability) than any other combinations;(5) Genetic distance was positively correlated with panicle number, grain length and length-to-width ratio(P 0.05) and negatively correlated with grain width, grain yield, seed-setting rate, as well as mid-parent heterosis, standard heterosis over check, and specific combining ability for grain yield(P 0.01). These heterotic groups and patterns and their argonomic traits will provide useful information for future hybrid rice breeding programs.     

欧洲玉米种质BC8241Ht衍生系的SRAP多态性与亲缘关系分析

Analyzed and identified SRAP polymorphism and genetic relationship on derived lines from Europe maize germplasm BC8241Ht at DNA molecular level,27 SRAP primer combinations were used to amplify the genome DNA of 21 maize lines of including derived lines from BC8241Ht.Total of 275 SRAP bans were observed and 131 out of these(47.6%) were polymorphic,and the polymorphism indicated that 21 maize lines used in the present study had abundant genetic diversity.The cluster analysis based on SRAP markers showed that 10 BC8241Ht derived lines were clustered in one group,but they were further clustered in first or third sub-groups.The close genetic relationship existed in 10 derived lines from Europe maize germplasm BC8241Ht,but the genetic differences also existed each other in the derived lines.In the course of improving the germplasm and its derived lines,they should be avoided mixing with Lvdahonggu,Tangsipingtou,PN and Southwestern local germplasm,and it can be improved by introducing tropical,subtropical germplasm.     

Genomic prediction of the performance of hybrids and the combining abilities for line by tester trials in maize

The two most important activities in maize breeding are the development of inbred lines with high values of general combining ability(GCA)and specific combining ability(SCA),and the identification of hybrids with high yield potentials.Genomic selection(GS)is a promising genomic tool to perform selection on the untested breeding material based on the genomic estimated breeding values estimated from the genomic prediction(GP).In this study,GP analyses were carried out to estimate the performance of hybrids,GCA,and SCA for grain yield(GY)in three maize line-by-tester trials,where all the material was phenotyped in 10 to 11 multiple-location trials and genotyped with a mid-density molecular marker platform.Results showed that the prediction abilities for the performance of hybrids ranged from 0.59 to0.81 across all trials in the model including the additive effect of lines and testers.In the model including both additive and non-additive effects,the prediction abilities for the performance of hybrids were improved and ranged from 0.64 to 0.86 across all trials.The prediction abilities of the GCA for GY were low,ranging between-0.14 and 0.13 across all trials in the model including only inbred lines;the prediction abilities of the GCA for GY were improved and ranged from 0.49 to 0.55 across all trials in the model including both inbred lines and testers,while the prediction abilities of the SCA for GY were negative across all trials.The prediction abilities for GY between testers varied from-0.66 to 0.82;the performance of hybrids between testers is difficult to predict.GS offers the opportunity to predict the performance of new hybrids and the GCA of new inbred lines based on the molecular marker information,the total breeding cost could be reduced dramatically by phenotyping fewer multiple-location trials.     

Genetic analysis and QTL mapping of stalk cell wall components and digestibility in maize recombinant inbred lines from B73 × By804

The cell wall composition and structure of the maize stalk directly affects its digestibility and in turn its feed value.Previous studies of stem quality have focused mostly on common maize germplasm,and few studies have focused on high-oil cultivars with high grain and straw quality.Investigation of the genetic basis of cell wall composition and digestibility of maize stalk using high-oil maize is desirable for improving maize forage quality.In the present study,a high-oil inbred line(By804)was crossed as male parent with the maize inbred line B73 to construct a population of 188 recombinant inbred lines(RILs).The phenotypes of six cell-wall-related traits were recorded,and QTL analysis was performed with a genetic map constructed with SNP markers.All traits were significantly correlated with one another and showed high broad-sense heritability.Of 20 QTLs mapped,the QTL associated with each trait explained 10.0%–41.1%of phenotypic variation.Approximately half of the QTL each explained over 10%of the phenotypic variation.These results provide a theoretical basis for improving maize forage quality by marker-assisted selection.     

Genome-wide association study and genomic prediction of Fusarium ear rot resistance in tropical maize germplasm

Fusarium ear rot(FER)is a destructive maize fungal disease worldwide.In this study,three tropical maize populations consisting of 874 inbred lines were used to perform genomewide association study(GWAS)and genomic prediction(GP)analyses of FER resistance.Broad phenotypic variation and high heritability for FER were observed,although it was highly influenced by large genotype-by-environment interactions.In the 874 inbred lines,GWAS with general linear model(GLM)identified 3034 single-nucleotide polymorphisms(SNPs)significantly associated with FER resistance at the P-value threshold of 1×10^-5,the average phenotypic variation explained(PVE)by these associations was 3%with a range from 2.33%to 6.92%,and 49 of these associations had PVE values greater than 5%.The GWAS analysis with mixed linear model(MLM)identified 19 significantly associated SNPs at the P-value threshold of 1×10^-4,the average PVE of these associations was 1.60%with a range from 1.39%to 2.04%.Within each of the three populations,the number of significantly associated SNPs identified by GLM and MLM ranged from 25 to 41,and from 5 to 22,respectively.Overlapping SNP associations across populations were rare.A few stable genomic regions conferring FER resistance were identified,which located in bins 3.04/05,7.02/04,9.00/01,9.04,9.06/07,and 10.03/04.The genomic regions in bins 9.00/01 and 9.04 are new.GP produced moderate accuracies with genome-wide markers,and relatively high accuracies with SNP associations detected from GWAS.Moderate prediction accuracies were observed when the training and validation sets were closely related.These results implied that FER resistance in maize is controlled by minor QTL with small effects,and highly influenced by the genetic background of the populations studied.Genomic selection(GS)by incorporating SNP associations detected from GWAS is a promising tool for improving FER resistance in maize.     

贵州常用玉米自交系的SSR遗传分析

Genetic variation was analyzed of 35 maize inbred lines in Guizhou with SSR.Selected 10 core-primers which could test 75 allele sites in sample of 35 inbred lines.The average number of allele per SSR locus was 7.5 with arrange from 5 to 14.The average of polymorphic information content(PIC) was 0.739.Gene locus among the 35 inbred lines ranged from 0.154 to 0.838 with an average of 0.513.The clustering results showed that the inbred lines could be classified into 7 groups.The clustering results were consistent with the groups based on the available.The local germplasm lines could be divided into three heterotic groups,showed the local germplasm had wide genetic basis.     

Comparison of Grain Quality Characteristics Between F1 Hybrids and Their Parents in Indica Hybrid Rice

Sixteen widespread elite indica parents including seven CMS lines and nine restorer lines, and their 63 F1 hybrids were chosen to compare the eleven traits of grain quality. Overall results showed that the frequency of negative over-dominance, dominance and partial dominance was much higher than that of positive ones and heterosis, indicating that the values of F1 hybrids were generally lower than the means of their parents in quality characteristics. There existed apparent disparity in grain quality performance among F1 hybrids varied with the traits. The characteristics of chalky area percentage, chalky grain percentage, gel consistency and head rice recovery had a great variation in all kinds of tested heterosis indices including the mid-parent heterosis index, over high-value parent heterosis index and over low-value parent heterosis index, which suggested that special attention should be paid to the selection of F1 hybrids in these traits in breeding. The mean values of F1 hybrids were significantly lower than those of their higher parents in all the traits but close to or significantly lower than those of their mid-parent values except for kernel length and amylose content; and significantly higher than those of their lower parents except for brown rice recovery, milled rice recovery and gel consistency.     

qRgls1.06, a major QTL conferring resistance to gray leaf spot disease in maize

Gray leaf spot(GLS)caused by Cercospora zeae-maydis and C.zeina is an extremely devastating leaf disease that limits maize production annually.The use of GLS-resistant maize hybrids is the most cost-effective approach for reducing losses.Resistance to GLS is quantitatively inherited in maize(Zea mays L.)and further sources of resistance remain to be analyzed.Here,we detected qRgls1.06,a major quantitative trait locus for GLS resistance in bin 1.06 that explained approximately 55%of the phenotype variance.Fine mapping over 2 consecutive years localized qRgls1.06 to a 2.38-Mb region.Homozygous qRgls1.06^WGR/WGR plants in DZ01 background displayed higher GLS resistance and 100-grain weight than DZ01 plants.The GLS responses of several susceptible elite inbred lines were improved by the introduction of qRgls1.06 by marker-assisted backcrossing.Our findings extend the understanding of the genetic basis of resistance to GLS and provide a set of resistant germplasm for genetic improvement of resistance to GLS in maize.     

Marker-assisted Selection of ZmC4Ppc in Rice Breeding and Yield Trait Performances of Advanced Lines

The full-length of intact Zea mays gene for phosphoenolpyruvate carboxylase gene (ZmC4Ppc) is 6 781 bp. The products of PCR for this gene were not clear with poor repeatability, resulting in that it was difficult for marker-assisted selection (MAS) both in rice and maize. For selecting the markers for MAS, sequences presented only in maize rather than in rice were identified by BLAST, and used for primer design using Primer Premier 5.0. A pair of specific primer termed MRpc (Forward: 5' AAGCAGGGAAGCGAGACG 3', Reverse: 5' GATTGCCGCCAGCAGTAG 3') was used for selection of transformed rice, and ZmC4Ppc could be highly and constitutively expressed at each tested developmental stages in the transformed rice selected by using MRpc. Thus, MRpc was used for MAS of progenies carrying ZmC4Ppc gene in rice and some restorer lines with ZmC4Ppc (e.g. FPM881) derived from ZmC4Ppc-transformed Kitaake backcrossed with a restorer line Shuhui 881 were obtained. The analyses on genetic background, PEPCase activity, net photosynthetic rate, general combining ability (GCA) and specific combining ability (SCA) of FPM881 showed that similarity of genetic background reached above 95%, the PEPCase and net photosynthetic rate were higher than those of the control, and some of the progenies carrying ZmC4Ppc gene had better GCA and SCA for grain yield per plant, number of panicles per plant, and 1000-grain weight than those of the control. This suggested that the introduction of maize ZmC4Ppc gene via MAS and its stable expression could increase grain yield of rice and would likely provide a pathway for rice varietal improvement.     

双低油菜新品种苏油1号超高产的生育特征及关键栽培技术

通过连续５年双没菜新品种苏油１号的多点试验示范,明确了３７５０ｋｇ／ｈｍ＾２以上的产量构成、角果群分布、群体结构、苗情动态等特征。根据苏油１号的生育特性,提出了适期早播培育壮苗,适当早栽、控制基础群体;合理化调,增降能力;科学施肥,确保高产需要;立足”三防”控制“三害”等关键栽培技术。     

富含11S大豆分离蛋白中试规模提取及其在冰淇淋和面制品中的应用

11S球蛋白是大豆蛋白中的主要成分,具有优良的加工特性.本文报道了中试水平上提取富含11S组分大豆分离蛋白技术,及其添加到冰淇淋和面粉中对产品特性的影响.试验结果表明,中试生产所得到的富含11S组分分离蛋白中,11S组分的含量达81.3%(占总蛋白含量).添加6%左右的富含11S组分大豆分离蛋白代替冰淇淋原料中的脱脂奶粉可提高冰淇淋的膨胀率,并具有良好的风味;在中等筋度的小麦粉中添加3%的富含11S组分分离蛋白,可提高面团吸水率、面团形成时间和面团稳定性,粉质评价值得到提高.     

全膜覆土栽培对作物的水温效应

为揭示全膜覆土栽培对作物的增产机理,在大田条件下分析了全膜覆土、传统地膜覆盖及露地栽培春小麦的土壤温度、土壤含水量、灌浆速率,以及两茬春小麦和一茬马铃薯的产量、水分利用效率和经济效益的差异。结果表明,与露地栽培相比,全膜覆土显著提高了春小麦生长前期耕层地温,降低了生长后期地表温度,同时起到保水和充分利用土壤深层水分的作用。全膜覆土春小麦的籽粒灌浆速率峰值出现时间和灌浆持续时间均比露地和地膜覆盖小麦分别推后3和6 d,平均灌浆速率分别提高0.65%和6.15%。全膜覆土栽培技术可连续提高三茬作物的产量及水分利用效率,使其总纯收益比露地和地膜覆盖处理分别增加26.07%和10.76%。     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).