O objetivo deste trabalho foi avaliar as características fitotécnicas e bromatológicas dos genótipos de milho para a produção de silagem, bem como, verificar se as diferentes bases genéticas (híbridos simples, triplo, duplo, intervarietal e variedades cultivadas) ou a textura dos grãos (duro, semiduro e dentado) alteram a indicação de genótipos para a produção silagem. O experimento foi realizado na área experimental da Universidade Tecnológica Federal do Paraná (UTFPR), Campus Dois Vizinhos no período de outubro de 2009 a março de 2010. Avaliaram-se os ensaios: centro superprecoce (32 genótipos), sul superprecoce (30 genótipos) e sul precoce normal (36 genótipos) da Rede Nacional de Genótipos de Milho, fornecidos pela Embrapa Milho e Sorgo (Sete Lagoas, MG). O experimento foi conduzido segundo o delineamento de blocos ao acaso com duas repetições e foram avaliados caracteres fitomorfológicos e bromatológicos da cultura do milho. Para cada ensaio os genótipos foram agrupados conforme as suas bases genéticas e posteriormente conforme a textura do grão, aplicando-se o teste de Scheffée, após realizou-se o teste de Scott-Knott. Como resultados, verificou-se que não existe influência da base genética nem da textura dos grãos na indicação de genótipos. Porém, existem genótipos que se destacam para a recomendação para a produção de silagem de milho. / The aim of this work was to evaluate the phytotechnical and bromatological characteristics of corn (maize) genotypes for silage production, and to verify whether the different genetic bases (single, three-way, double and inter-varietal hybrids and cultivated varieties) and grain texture (hard, semi-hard and dent) affect genotype suitability for silage production. The experiment was carried out in the experimental area of Paraná Federal Technology University (UTFPR) at the Dois Vizinhos Campus between October 2009 and March 2010. The trial cultivars evaluated were: “Centro superprecoce” [Central Super Early] (32 genotypes), “Sul superprecoce” [South Super Early] (30 genotypes) and “Sul precoce normal” [Central Normal Early] (36 genotypes) from the Rede Nacional de Genótipos de Milho [National Network of Corn Genotypes], provided by Embrapa Milho e Sorgo (Sete Lagoas, MG). The experimental arrangement was a randomized blocks design with two replications and the phytomorphological and bromatological characters of the corn crop were evaluated. In each trial, genotypes were grouped according to their genetic bases and then on the basis of grain texture, using the Scheffée method, and next, a Scott-Knott test was run. Results showed that neither the genetic base nor the grain texture affected genotype suitability. However, taken individually, some of the genotypes could be recommended for corn silage production.

O objetivo deste trabalho foi avaliar as características fitotécnicas e bromatológicas dos genótipos de milho para a produção de silagem, bem como, verificar se as diferentes bases genéticas (híbridos simples, triplo, duplo, intervarietal e variedades cultivadas) ou a textura dos grãos (duro, semiduro e dentado) alteram a indicação de genótipos para a produção silagem. O experimento foi realizado na área experimental da Universidade Tecnológica Federal do Paraná (UTFPR), Campus Dois Vizinhos no período de outubro de 2009 a março de 2010. Avaliaram-se os ensaios: centro superprecoce (32 genótipos), sul superprecoce (30 genótipos) e sul precoce normal (36 genótipos) da Rede Nacional de Genótipos de Milho, fornecidos pela Embrapa Milho e Sorgo (Sete Lagoas, MG). O experimento foi conduzido segundo o delineamento de blocos ao acaso com duas repetições e foram avaliados caracteres fitomorfológicos e bromatológicos da cultura do milho. Para cada ensaio os genótipos foram agrupados conforme as suas bases genéticas e posteriormente conforme a textura do grão, aplicando-se o teste de Scheffée, após realizou-se o teste de Scott-Knott. Como resultados, verificou-se que não existe influência da base genética nem da textura dos grãos na indicação de genótipos. Porém, existem genótipos que se destacam para a recomendação para a produção de silagem de milho. / The aim of this work was to evaluate the phytotechnical and bromatological characteristics of corn (maize) genotypes for silage production, and to verify whether the different genetic bases (single, three-way, double and inter-varietal hybrids and cultivated varieties) and grain texture (hard, semi-hard and dent) affect genotype suitability for silage production. The experiment was carried out in the experimental area of Paraná Federal Technology University (UTFPR) at the Dois Vizinhos Campus between October 2009 and March 2010. The trial cultivars evaluated were: “Centro superprecoce” [Central Super Early] (32 genotypes), “Sul superprecoce” [South Super Early] (30 genotypes) and “Sul precoce normal” [Central Normal Early] (36 genotypes) from the Rede Nacional de Genótipos de Milho [National Network of Corn Genotypes], provided by Embrapa Milho e Sorgo (Sete Lagoas, MG). The experimental arrangement was a randomized blocks design with two replications and the phytomorphological and bromatological characters of the corn crop were evaluated. In each trial, genotypes were grouped according to their genetic bases and then on the basis of grain texture, using the Scheffée method, and next, a Scott-Knott test was run. Results showed that neither the genetic base nor the grain texture affected genotype suitability. However, taken individually, some of the genotypes could be recommended for corn silage production.

No description available.

Gamma-zein, a proline-rich protein from corn endosperm, was investigated at the molecular level. Immunological and electrophoretic data indicated that gamma-zein was deposited into protein bodies in corn endosperm. Both isolated polysomes and poly(A)⁺ mRNA were found to direct in vitro synthesis of gamma-zein in a wheat germ system. In vitro synthesized gamma-zein was immunoprecipitated from the total in vitro translation products. A cDNA expression library was constructed by reverse transcription of total poly(A)⁺ mRNA using pUC8 plasmid as vector and <i>E. coli</i> strain DH1 as host. The library was screened for the expression of gamma-zein and alpha-zein by specific antibodies. The library was also screened with ³²P-labeled gamma-zein and alpha-zein cDNA probes. The results indicated that gamma-zein and its fragments were readily expressed in <i>E. coli</i> while alpha-zein was not. Seven independently selected clones, six of which were selected by antibody and one by a cDNA probe, were sequenced. A comparison of sequence information from seven clones revealed that their overlapping regions were identical. This suggests that gamma-zein is encoded by a single U gene. This finding is in conflict with what was expected on the basis of extensive charge heterogeneity of gamma-zein in isoelectric focusing. Individual bands cut from an IEF gel were rerun and shown to give several bands suggesting that the charge heterogeneity of gamma-zein may be an artifact. Sequence information of gamma-zein indicated that the gene encodes a mature protein whose primary structure includes 204 amino acids and has a molecular weight of 21,824 daltons. There are eight essentially identical tandem repeats of the hexapeptide Pro-Pro-Pro-Val-His-Leu and two of the octapeptide Gln-Pro-His-Pro-Cys-Pro-Cys-Gln in the N-terminal one-half of the polypeptide. The codon specifying the third proline in the hexapeptide repeating unit is identical, CCG, in all eight repeats. It is likely that these highly conserved tandem repeats are of critical importance to the function of gamma-zein which is presently unknown. Alternatively, it is conceivable that selective pressures responsible for conserving these tandem repeats may be operating at the nucleic acid level. / Ph. D. / incomplete_metadata

The specific goal of this study was to construct and test transcriptional fusions of zein promoters and a yeast reporter gene that will serve as part of a two plasmid system that will allow for the identification of maize transcriptional regulators of zein genes. Zein genes are expressed coordinately and tempO~ly during endosperm development and are controlled at the transcriptional level (Pedersen et aL, 1980; Kodryzcki et al. t 1989). The accumulation of zein proteins in the endosperm presents an ideal model system to study plant gene regulation. These proteins are synthesized only in the endosperm tissue, and their concentration in the endosperm determine the nutritional quality of the seed. Because of the coordinate and temporal regulation of zein gene transcription, there is a strong likelihood that there exists positive regulatory elements of zein gene expression during early endosperm development. We know that the control of storage protein gene expression is mediated by regulatory elements in the endosperm of maize seeds. It has been shown that the recessive mutation opaque-2 (02) specifically reduces the 22,000 zein polypeptide .. Schmidt et at (1990) and Aukennan et at (1991) show that the wild-type 02 encodes a protein containing a basic leucine zipper domain / Master of Science

Maize ß-glucosidase is implicated in phytohormone catabolism, disease resistance mechanisms, and also the catabolism of various ß-D-glucosides. The enzyme expressed in maize sporophytes is encoded by a highly polymorphic locus, Glul (chromosome 10). In the present study, maize ß-glucosidase was purified to homogeneity by using differential solubility and chromatography. The enzyme is soluble and synthesized adaptively after germination. The isoelectric point (pl) of the native enzyme is 4.9-5.0 and its temperature and pH optima are 40°C and 6.8, respectively. The active enzyme is temperature·sensitive and composed of two identical, non-covalently associated and catalytically inactive polypeptides (60 kD each). Enzyme catalysis shows dominant aryl ß-glucosidase and ß-fucosidase activities compared to cellobiase activity. Activity is (1) influenced by the configuration of the C-4 and C-6 atoms on the glycone moeity and by the substrate chain length, (2) possibly mediated by an imidazole ring and a terminal α-amino group in the enzyme catalytic and binding sites, respectively, (3) dependent on intra-chain disulfide bonds to maintain the enzyme conformation, and (4) inhibited competitively by the end product, glucose. The sporophytic specificity of Glul expression might be controlled by tightly linked cis- and trans- acting regulatory elements. One of the several null mutations, with an apparent allelism to Glul locus, (l) complements in trans when combined with normal Glul alleles, and (2) probably affects a shift in the tissue-specific expression of Glul locus (from sporophytic to gametophytic). Another structural gene, GIu3, encoding a soluble, sporophyte-specific, and electrophoretically-invariant ß-glucosidase isoenzyme is present based on hydrodynamic properties, size, surface net charge, peptide map, quaternary structure, and enzyme kinetics. / Ph. D.

Thesis (PhD)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Gray leaf spot (GLS) of maize, caused by the fungus Cercospora zeae-maydis, can reduce grain yields by up to 60% and it is now recognized as one of the most significant yield-limiting diseases of maize in many parts of the world. The most sustainable and long-term management strategy for GLS will rely heavily on the development of high-yielding, locally adapted GLS resistant hybrids. Molecular markers could be useful to plant breeders to indirectly select for genes affecting GLS resistance and to identify resistance genes without inoculation and at an early stage of plant development. Only two studies in the USA have examined quantitative trait loci (QTL) association with GLS resistance. The aim of this study was to map GLS resistance genes in a resistant Seed Co LTD, Zimbabwean inbred line. Molecular markers linked to the GLS resistance QTL were identified by using the amplified fragment length polymorphism (AFLP) technique together with bulked segregant analysis. Eleven polymorphic AFLP fragments were identified and converted to sequence-specific PCR (polymerase chain reaction) markers. Eight of the 11 converted AFLP markers were added to the maize marker database of the University of Stellenbosch. Five of the 8 converted AFLP markers were polymorphic between the resistant and the susceptible parent. They were amplified on the DNA of 230 plants of a segregating F2 population and linkage analysis was performed with MAPMAKER/EXP. Two linkage groups consisting of two markers each, with a linkage distance of 10.4 cM (LOD 22.83) and 8.2 cM (LOD 55.41) between the two markers, were identified. QTL mapping with MAPMAKER/QTL confirmed the presence of QTL in both linkage groups. Two publicly available recombinant inbred families (Burr et a/., 1988) were used to localize the converted AFLP markers on the genetic map of maize. The QTL, which were identified with the AFLP markers, were mapped to chromosomes 1 and 5. Another AFLP marker was mapped to chromosome 2 and a further to chromosome 3. To obtain more precise localizations of the QTL on chromosomes 1 and 5, sequence-tagged site markers and microsatellite markers were used. The markers were amplified on the DNA of the 230 plants of the F2 population and linkage analysis was performed with MAPMAKER/EXP. The order of the markers was in agreement with the UMC map of the Maize Genome Database. Interval mapping using MAPMAKERlQTL and composite interval mapping using QTL Cartographer were performed. The QTL on chromosome 1 had a LOD score of 21 and was localized in bin 1.05/06. A variance of 37% was explained by the QTL. Two peaks were visible for the QTL on chromosome 5, one was localized in bin 5.03/04 and the other in bin 5.05/06. Both peaks had a LOD score of 5 and 11% of the variance was explained by the QTL. To test the consistency of the detected QTL, the markers flanking each QTL were amplified on selected plants of two F2 populations planted in consecutive years and regression analysis was performed. Both the QTL on chromosome 1 and the QTL on chromosome 5 were detected in these populations. Furthermore, the presence of a QTL on chromosome 3 was confirmed with these populations. A variance of 8 -10% was explained by the QTL on chromosome 3. In this study, a major GLS resistance QTL was thus mapped on chromosomes 1 and two minor GLS resistance QTL were mapped on chromosomes 3 and 5 using a resistant Seed Co LTD, Zimbabwean inbred line. Markers were identified which could be used in a marker-assisted selection program to select for the GLS resistance QTL. / AFRIKAANSE OPSOMMING: Grys blaarvlek (GBV) van mielies, veroorsaak deur die swam Cercospora zeaemaydis, kan graanopbrengs met tot 60% verlaag en word beskou as een van die vernaamste opbrengs-beperkende siektes wêreldwyd. Die toepaslikste langtermyn stragtegie vir GBV beheer sal wees om plaaslike mieliebasters met hoë opbrengs en GBV weerstand te ontwikkel. Molekulêre merkers kan nuttig deur plantetelers gebruik word om weerstandsgene te selekteer. Seleksie is moontlik in die afwesigheid van inokolum en op 'n vroeë stadium van plant ontwikkeling. Slegs twee vorige studies (in die VSA) het kwantitatiewe-kenmerk-Iokusse (KKL), vir GBVweerstand ondersoek. Die doel van hierdie studie was om die GBV weerstandsgene in 'n weerstandbiedende ingeteelde lyn (Seed Co BPK, Zimbabwe) te karteer. Molekulêre merkers gekoppel aan die GBV weerstands KKL is geïdentifiseer deur gebruik te maak van die geamplifiseerde-fragmentlengte-polimorfisme- (AFLP-) tegniek en gebulkte-segregaat-analise. Elf polimorfiese merkers is geïdentifiseer en omgeskakel na volgorde-spesifieke PKR (polimerase kettingreaksie) merkers. Agt van die elf omgeskakelde AFLP-merkers is by die mieliemerker databasis van die Universiteit van Stellenbosch gevoeg. Vyf van die 8 omgeskakelde AFLP-merkers was polimorfies tussen die bestande en vatbare ouers. Hulle is geamplifiseer op die DNA van 230 plante van 'n segregerende F2-populasie en is gebruik in 'n koppelingstudie met MAPMAKER/EXP. Twee koppelingsgroepe, elk bestaande uit twee merkers, met onderskeidelik koppelingsafstande van 10.4 eM (LOD 22.83) en 8.2 eM (LOD 55.41) tussen die merkers, is geïdentifiseer. KKL-kartering het getoon dat KKL in albei koppelingsgroepe aanwesig is. Twee kommersieël beskikbare, rekombinant-ingeteelde families (Burr et aI., 1988) is gebruik om die omgeskakelde AFLP-merkers op die mielie genetiese kaart te plaas. Die KKL wat met die AFLP-merkers geïdentifiseer is, is gekarteer op chromosome 1 en 5. 'n Verdere AFLP-merker is op chromosoom 2 gekarteer en 'n ander op chromosoom 3. Ten einde die KKL op chromosome 1 en 5 meer akkuraat te karteer, is volgordege- etikeerde en mikrosatelliet merkers gebruik. Die merkers is geamplifiseer op die DNA van die 230 plante van die F2-populasie en koppelings-analises is uitgevoer. Die volgorde van die merkers was dieselfde as die van die UMC-kaart in die Mielie Genoom Databasis. Interval kartering met MAPMAKER/QTL en komposiet interval kartering met QTL Cartographer is uitgevoer. Die KKL op chromosoom 1 het 'n LOD-telling van 21 gehad en is in bin 1.05/06 geplaas. Die KKL was verantwoordelik vir 37% van die variansie. Twee pieke was onderskeibaar vir die KKL op chromosoom 5, een in bin 5.03/04 geleë en die ander in bin 5.05/06. Elke piek het 'n LOD-telling van 5 gehad en die twee KKL was verantwoordelik vir 11% van die variansie. Om die herhaalbaarheid van die effek van die KKL te toets is die merkers naaste aan elke KKL geamplifiseer op geselekteerde plante van twee F2-populasies wat in opeenvolgende jare geplant is. Regressie analise is op die data gedoen. Beide die KKL op chromosoom 1 en die KKL op chromosoom 5 kon in hierdie populasies geïdentifiseer word. Verder kon die aanwesigheid van 'n verdere KKL op chromosoom 3 in hierdie populasies bevestig word. Laasgenoemde KKL was verantwoordelik vir 8-10% van die totale variansie. In hierdie studie is daar dus 'n hoof GBV-weerstands KKL gekarteer op chromosoom 1 en twee kleiner GBV-weerstands KKL gekarteer op chromosome 3 en 5. Merkers is geïdentifiseer wat moontlik in merker-gebaseerdetelingsprogramme gebruik kan word om plante te selekteer wat die GBVweerstands KKL het.

Subsidiary mother cell (SMC) divisions during stomatal complex formation in Zea mays are asymmetric generating a small subsidiary cell (SC) and a larger epidermal cell. Mutants with a high number of abnormally shaped subsidiary cells include the brick1 (brk1) and discordia1 (dcd1) mutants. BRK1 is homologous to HSPC300, an ARP2/3 complex activator, and is involved in actin nucleation while DCD1 is a regulatory subunit of the PP2A phosphatase needed for microtubule generation (Frank and Smith, 2002; Wright et al. 2009). Possible causes of the abnormal SCs in brk1 mutants include a failure of the SMC nucleus to polarize in advance of mitosis, no actin patch, and transverse and/or no PPBs (Gallagher and Smith, 2000; Panteris et al 2006). The abnormal subsidiary mother cell division in dcd1 is due to correctly localized, but disorganized preprophase bands (PPBs; Wright et al. 2009). The observation that brk1 has defects in PPB formation and that the dcd1 phenotype is enhanced by the application of actin inhibitors led us to examine the dcd1; brk1 double mutant (Gallagher and Smith, 1999). We found that dcd1; brk1 double mutants demonstrate a higher percentage of aberrant SCs than the single mutants combined suggesting that these two mutations have a synergistic and additive effect on SC formation. Our observations and results are intriguing and the future step will be to quantitate the abnormal PPBs and phragmoplasts in the double and single mutants using immunolocalization of tubulin and actin as well as observations of live cells expressing tubulin-YFP.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Typescript (photocopy). / Digitized by Kansas Correctional Industries