The purpose of this work was to analyze whole kernel corn for such factors as succulence, pericarp content and size of kernels and to check for possible relationships between these values and the subjective tests for tenderness and maturity and flavor. In addition the purpose of this investigation was to accumulate values for succulence, pericarp content and kernel size for sweet corn grown in this area. All varieties were harvested in August 1952, when their moisture content was close to 70 percent. Succulence of this canned corn ranged from 24.7 to 15.2 ml. for 17 varieties; and the six varieties recommended ranged from 24.7 to 22.8 ml. Pericarp content was determined by the standard method, and it was found to be very low when compared with similar data from other sections of the country. Values ranged from 0.6230 to 1.1951 percent, and the six best varieties recommended for all factors together, from 0.6230 to 0.7872 percent. The largest diameters in inches of twenty kernels were measured with a micrometer. Size ranged from 7.0685 to 8.5005 inches for twenty kernels. The same six best varieties ranged from 7.0885 to 7.8730 inches. In addition to these three objective tests a panel of seven members graded this corn for maturity and tenderness on a basis of forty points, and flavor on a basis of twenty points. For maturity and tenderness all varieties lie between 37.1 and 26.4, with the six varieties recommended between 37.1 and 35.7. For flavor the range for all varieties is from 17.6 to 13.3. The same six varieties are from 17.6 to 15.7. Results show that the combination test proposed by Kramer can be applied successfully, and that pericarp content can be omitted in this combination test for corn grown under irrigation in this part of the country. In fact, succulence and kernel size predicted maturity with a multiple correlation of 0.936. / Graduation date: 1953

Typescript (photocopy). / Digitized by Kansas Correctional Industries

A study was made to determine (1) the influence of plant spacing and nitrogen fertilizer on the yield, percentage of soluble solids, the toughness of the pericarp, and protein content of embryos and kernels of hybrid sweet corn, and (2) the influence of locally on the protein content of field corn varieties. The highest yield and weight of ears of sweet corn are obtained with plants spaced 6 inches apart. Of the three varieties, the medium-late maturing Seneca Chief is more desirable from the standpoint of higher yields and weight of ears. Northern Cross had the lowest number of total ears when grown 9 inches apart, and the other two varieties with 12 inches between plants in the row. Differences in earliness, yield, the weight of ears, and the number of ears per plot are found among the varieties studied. The number of shoots or tillers of Seneca Chief is higher than that of Northern Cross or Seneca Arrow; with increases in spacing the number of shoots per plant increases. The early maturing variety Northern Cross was less desirable in that the kernels at harvest contained a lower percentage of soluble solids, had the toughest pericarp; however, it contained a higher average percentage of total protein (15.31) than either Seneca Arrow (14.50) and Seneca Chief (13.56). Northern Cross also contained a higher average percentage of total protein in the embryos (17.00) than either Seneca Chief (16.44) and Seneca Arrow (14.87). The embryo protein, considered to be more digestible than the protein of the endosperm was not influenced by spacing treatments. Under the conditions of this experiment, there was no association between the amount of nitrogen fertilizer and the percentage of soluble solids, toughness of the pericarp, protein content, and yield of sweet corn. The supply of nitrogen seemed adequate since the corn crop followed a crop of soybeans. Considering the entire experiment, regardless of variety, spacing, and fertilizer levels, the increase in yield decreased the food value of sweet corn in terms of the protein content of the kernels but did not influence the protein content of the embryos this cannot be considered conclusive because of the limited experimental period and small number of hybrid studied. lt was found that the total protein content of kernel: of three field corn varieties grown in Central America varied more between locations than between varieties grown at the same location. The average protein content of the three field corn varieties ranged from 8.44% to 12.12%. Embryos of the field corn varieties contained a higher percentage of total protein than embryos of sweet corn. Thie fact suggests that field corn, which is low in quality from the standpoint of sweetness, contained a higher digestible protein content than sweet corn. / Master of Science

Graduation date: 1954

A rapid non-destructive Image Analysis (IA) technique was developed for the determination of maize kernel endosperm vitreousness. Kernels were analysed using a Leica Q-Win Q500 IW-DX Image Analyser fitted with Leica Q-Win software and connected to a Sony XC-75 CCD camera. Kernel translucency measurements were optimised by using a light system that involved positioning whole kernels on top of a mask containing round illuminated areas (circles), smaller than the projected areas of the kernels, allowing light to shine through the kernels only. Correction factors allowing for constant illumination of kernels were developed to adjust for kernel size variation in relation to constant light area. Similarly, a correction factor for the effect of kernel thickness on detected translucency values were developed. Significant correlations were found between corrected translucency values and vitreous and opaque endosperm yields as determined by hand dissection. These were: translucency as a percentage of the whole kernel and vitreous endosperm (mass%) (Translucency 1), r = 0.77, p<0.00001, and Translucency 1 and opaque endosperm (mass%), r = -0.72, p<0.00001 for white maize. Similar correlations were found for translucency as a percentage of endosperm (Translucency 2). Correlation coefficients increased significantly after kernel thickness corrections. Significant negative correlations were also found between corrected translucency values and Floating Number. For yellow maize, Translucency 1 correlation coefficients was r = 0.78, p<0.00001 and r = -0.71, p<0.00001 respectively with similar correlations for Translucency 2. Correlations were obtained after applying both correction factors for exposure and thickness. The IA technique was evaluated for predicting the yield of vitreous endosperm products during dry maiz~ milling in laboratory and industrial-scale milling trials. Significant positive correlations were found between corrected translucency values and yields of milling products from vitreous endosperm. Experiments using a laboratory-scale experimental roller milling test without a degerming stage produced the following correlations: between Translucency 1 and semolina yield (mass%), 0.74, p<0.001 and Translucency 2 and semolina yield (mass%), 0.70, p<0.001. For industrial-scale milling, a Bühler industrial-scale maize mill (3 tons per hour) was used. The correlation between Translucency 1 and extraction at degermer (degermer overtail yield) was 0.93, p<0.0001. There was a similar correlation for Translucency 2. Yellow maize was degermed using a pilot-scale Beall-type degermer and the correlation between Translucency 1 and flaking grits> 3.9 mm was 0.67, p< 0.001. The IA technique permits the non-destructive analysis of maize endosperm translucency on large samples of single kernels. It is suitable for rapid quantification of maize endosperm contents and predicting dry maize milling performance, as kernel translucency was significantly correlated with vitreousness in all instances. With further development of specific hardware and software, the technique has potential as an on¬line maize kernel classification system in industrial mills. As the method is non¬destructive, it is also suitable for classification of maize seed breeding material. It is also a potential method for the measurement of maize opacity as used by the wet milling industry, where opacity (the opposite of vitreousness) is related to maize starch yield. / Thesis (PhD(Food Science))--University of Pretoria, 2006. / Food Science / unrestricted

No description available.

Um dos principais desafios do melhoramento de milho doce é aumentar a eficiência da seleção para produtividade e qualidade dos grãos. Uma das formas de aumentar essa eficiência é a utilização de marcadores moleculares para auxiliar a seleção nos programas de melhoramento. Para isso, o estudo da herança por meio do mapeamento de QTL é uma ferramenta importante para o conhecimento da base genética dos caracteres e para gerar informações que possam ser utilizadas na seleção assistida por marcadores moleculares. O presente estudo teve como objetivo mapear QTL em testecrosses de milho doce para produção de grãos, seus componentes e caracteres de qualidade, e avaliar o efeito de diferentes testadores e ambientes no mapeamento de QTL. Para tanto, foi utilizada uma população obtida do cruzamento entre as linhagens B532 e B605 do mesmo grupo heterótico e contrastantes para diversos caracteres. Duzentas e cinqüenta e seis progênies F4:5 foram genotipadas com marcadores moleculares SNP para a construção do mapa genético. Posteriormente, essas progênies foram cruzadas com os testadores A36 e A17 de um grupo heterótico distinto do grupo da população. Os testecrosses obtidos foram avaliados em dois ambientes, Uberlândia, MG, e Itatiba, SP, em látices simples 16 x 16. Os caracteres avaliados foram produção de grãos (PG), número de fileiras de grãos (NF), comprimento de espiga (CE), diâmetro de espiga (DE), comprimento de grãos (CG), coloração de grãos (CL), maciez de grãos (MC) e doçura de grãos (DÇ). O método de mapeamento por intervalo composto expandido para múltiplos ambientes (mCIM) foi utilizado para mapear QTL e detectar a interação QTL x ambiente. Foram mapeados 116 QTL, sendo 21 para PG, 17 para NF, 22 para CE, 14 para DE, 12 para CG, 11 para CL, 11 para MC e 8 para DÇ. Com exceção de 2 QTL para NF que explicaram 12,19% e 10,03% e de 1 QTL para CE que explicou 10,48%, todos os outros explicaram menos de 10% da variância fenotípica. Considerando todos os caracteres, 91% dos QTL mapeados foram específicos para cada testador, evidenciando uma elevada interação QTL x testador. Dos 116 QTL mapeados apenas 22 apresentaram interação QTL x ambiente, indicando que houve baixa interação QTL x ambiente. Dessa forma, a maioria dos caracteres de importância econômica em milho doce foi controlada por muitos QTL de baixos efeitos na variação fenotípica, os quais apresentaram uma elevada interação QTL x testador e uma reduzida interação QTL x ambiente. O elevado número de QTL controlando os caracteres e a elevada interação QTL x testador mostram a complexidade da aplicação da seleção assistida no melhoramento de milho doce. / One of the main challenges in sweet corn breeding is to improve the efficiency of selection for grain yield and quality traits. The use of molecular markers would be a way to increase the selection efficiency in breeding programs. QTL mapping is an important tool for understanding the genetic basis of the traits and to generate information that can be used in marker assisted selection. This study aimed to map QTL in sweet corn testecrosses for grain yield, its components and quality traits, and evaluate the effect of different testers and environments in QTL mapping. For this study a population was obtained by crossing lines B532 and B605, from the same heterotic group and contrasting for different traits. Two hundred and fifty-six F4:5 progenies were genotyped with SNP markers for the construction of the genetic map. Subsequently, these progenies were crossed with the testers A36 and A17 from a different heterotic group than the population. The obtained testecrosses were evaluated in two environments, Uberlândia, MG, e Itatiba, SP, in a simple lattice design 16 x 16. The traits evaluated were: grain yield (PG); number of rows (NF); ear length (CE); ear diameter (DE); kernel depth (CG), kernel color (CL); kernel tenderness (MC) and kernel sweetness (DÇ). The composite interval mapping extended to multiple environments (mCIM) was used to map QTL and to detect the QTL x environment interaction. One hundred and sixteen QTL were mapped; with 21 for PG, 17 for NF, 22 for CE, 14 for DE, 12 for CG, 11 for CL, 11 for MC and 8 for DÇ. With the exception of 2 QTL for NF which explained 12%,19% and 10,03% and by 1 QTL for CE which explained 10,48%, all the others explained less than 10% of the phenotypic variance. Considering all of the traits, 91% of the mapped QTL were specific to each tester, indicating a high QTL x tester interaction. Out of the 116 QTL mapped, only 22 showed significant QTL x environment interaction, indicating that there was a small QTL x environment interaction. Thus, most traits of economic importance in sweet corn seem to be controlled by many QTL with small effects, which showed a large QTL x tester interaction and a small QTL x environment interaction. The large number of QTL controlling the traits and the large QTL x tester interactions demonstrate the complexity of the implementation of marker assisted selection in sweet corn breeding.

Um dos principais desafios do melhoramento de milho doce é aumentar a eficiência da seleção para produtividade e qualidade dos grãos. Uma das formas de aumentar essa eficiência é a utilização de marcadores moleculares para auxiliar a seleção nos programas de melhoramento. Para isso, o estudo da herança por meio do mapeamento de QTL é uma ferramenta importante para o conhecimento da base genética dos caracteres e para gerar informações que possam ser utilizadas na seleção assistida por marcadores moleculares. O presente estudo teve como objetivo mapear QTL em testecrosses de milho doce para produção de grãos, seus componentes e caracteres de qualidade, e avaliar o efeito de diferentes testadores e ambientes no mapeamento de QTL. Para tanto, foi utilizada uma população obtida do cruzamento entre as linhagens B532 e B605 do mesmo grupo heterótico e contrastantes para diversos caracteres. Duzentas e cinqüenta e seis progênies F4:5 foram genotipadas com marcadores moleculares SNP para a construção do mapa genético. Posteriormente, essas progênies foram cruzadas com os testadores A36 e A17 de um grupo heterótico distinto do grupo da população. Os testecrosses obtidos foram avaliados em dois ambientes, Uberlândia, MG, e Itatiba, SP, em látices simples 16 x 16. Os caracteres avaliados foram produção de grãos (PG), número de fileiras de grãos (NF), comprimento de espiga (CE), diâmetro de espiga (DE), comprimento de grãos (CG), coloração de grãos (CL), maciez de grãos (MC) e doçura de grãos (DÇ). O método de mapeamento por intervalo composto expandido para múltiplos ambientes (mCIM) foi utilizado para mapear QTL e detectar a interação QTL x ambiente. Foram mapeados 116 QTL, sendo 21 para PG, 17 para NF, 22 para CE, 14 para DE, 12 para CG, 11 para CL, 11 para MC e 8 para DÇ. Com exceção de 2 QTL para NF que explicaram 12,19% e 10,03% e de 1 QTL para CE que explicou 10,48%, todos os outros explicaram menos de 10% da variância fenotípica. Considerando todos os caracteres, 91% dos QTL mapeados foram específicos para cada testador, evidenciando uma elevada interação QTL x testador. Dos 116 QTL mapeados apenas 22 apresentaram interação QTL x ambiente, indicando que houve baixa interação QTL x ambiente. Dessa forma, a maioria dos caracteres de importância econômica em milho doce foi controlada por muitos QTL de baixos efeitos na variação fenotípica, os quais apresentaram uma elevada interação QTL x testador e uma reduzida interação QTL x ambiente. O elevado número de QTL controlando os caracteres e a elevada interação QTL x testador mostram a complexidade da aplicação da seleção assistida no melhoramento de milho doce. / One of the main challenges in sweet corn breeding is to improve the efficiency of selection for grain yield and quality traits. The use of molecular markers would be a way to increase the selection efficiency in breeding programs. QTL mapping is an important tool for understanding the genetic basis of the traits and to generate information that can be used in marker assisted selection. This study aimed to map QTL in sweet corn testecrosses for grain yield, its components and quality traits, and evaluate the effect of different testers and environments in QTL mapping. For this study a population was obtained by crossing lines B532 and B605, from the same heterotic group and contrasting for different traits. Two hundred and fifty-six F4:5 progenies were genotyped with SNP markers for the construction of the genetic map. Subsequently, these progenies were crossed with the testers A36 and A17 from a different heterotic group than the population. The obtained testecrosses were evaluated in two environments, Uberlândia, MG, e Itatiba, SP, in a simple lattice design 16 x 16. The traits evaluated were: grain yield (PG); number of rows (NF); ear length (CE); ear diameter (DE); kernel depth (CG), kernel color (CL); kernel tenderness (MC) and kernel sweetness (DÇ). The composite interval mapping extended to multiple environments (mCIM) was used to map QTL and to detect the QTL x environment interaction. One hundred and sixteen QTL were mapped; with 21 for PG, 17 for NF, 22 for CE, 14 for DE, 12 for CG, 11 for CL, 11 for MC and 8 for DÇ. With the exception of 2 QTL for NF which explained 12%,19% and 10,03% and by 1 QTL for CE which explained 10,48%, all the others explained less than 10% of the phenotypic variance. Considering all of the traits, 91% of the mapped QTL were specific to each tester, indicating a high QTL x tester interaction. Out of the 116 QTL mapped, only 22 showed significant QTL x environment interaction, indicating that there was a small QTL x environment interaction. Thus, most traits of economic importance in sweet corn seem to be controlled by many QTL with small effects, which showed a large QTL x tester interaction and a small QTL x environment interaction. The large number of QTL controlling the traits and the large QTL x tester interactions demonstrate the complexity of the implementation of marker assisted selection in sweet corn breeding.

The Matsqui area of the Lower Fraser Valley exhibits extreme soil heterogeneity, as the alluvial soils in the area have been deposited by the Fraser River as a series of coarse-textured ridges and finer-textured depressional areas. This variability poses some obvious problems with respect to agricultural management. The main aim of this study was to evaluate soil spatial variability in four fields, and to relate this soil variability to corn production and quality. Site conditions, topography, and soil chemical and physical variables were related to corn biomass and nutrient concentrations using conventional correlation/regression analyses, and more spatially representative techniques such as those provided by remote sensing and geographic information systems. Variations in such biophysical variables as soil moisture, elevation, and bulk density had consistent impacts on corn productivity, although these effects varied from field to field, being influenced by inherent soil properties and individual field management. Good relationships were found between pixel brightness values extracted from digitized colour infra-red photos and corn quality variables. In three out of four fields, near infra-red pixel values gave good estimates of total corn crude protein content. Significant relationships were also found between pixel brightness values and corn phosphorus and calcium contents in certain fields. The spatial variability of corn quality and biomass could be quantified using image analysis classification techniques. The resulting classified images indicate to the farm operator where high vs low quality corn is being produced, and thereby provide a tool for selectively managing and harvesting the fields. The relationships and quantification of corn productivity and quality in the fields can further be improved through incorporation of the image data with the biophysical data base using GIS techniques. A multiple regression equation showing a significant relationship between elevation and pixel brightness values, and total corn phosphorus concentration was incorporated within the GIS to produce a quantitative corn quality map for the field exhibiting this relationship. The GIS overlay capability facilitates the classification of several corn variables, and allows the results to be displayed in a spatial manner. For example, corn biomass and quality maps were overlain using GIS techniques, to produce a combination map which then reflected both the quality and quantity of corn found in the field. Through integration of remote sensing and GIS techniques, soil and crop variability can be displayed in a spatial manner. The output from such procedures can aid farm operators in making selective field management and harvesting decisions. / Land and Food Systems, Faculty of / Graduate

Made available in DSpace on 2015-03-26T13:42:33Z (GMT). No. of bitstreams: 1 texto completo.pdf: 244644 bytes, checksum: 7bb131def78ba69016b2b6a8a2dd140f (MD5) Previous issue date: 2014-02-27 / Linkage disequilibrium (LD) is defined as the non-random association between alleles of different loci in a population and association mapping (MA) refers to a statistically significant association between molecular marker and phenotypic trait. The objectives of this study were: (1) estimate the linkage disequilibrium in populations of popcorn related by cycles of selection using SNP markers, (2) compare the populations in the degree of LD, (3) evaluate changes in allele frequencies and (4) identify significant associations between markers and quality related characteristics of popcorn. In total 465 samples were evaluated, with 354 samples belonging to the population 'Viçosa' and 111 samples belonging to the population eija- asm Improvement Program popcorn, Federal University of Viçosa. The populations were subjected to the following cycles of selection: Viçosa cycle 1 and cycle 1 Beija-Flor, obtained after one cycle of selection among and within half-sib families, Viçosa cycle 4, obtained after four cycles of selection among and within half-sib families, Viçosa cycle 2 full-sib families (FIC), obtained after two cycles of selection among and within full-sib families, Viçosa S4, obtained by selection of progeny S4. Ninety-six SNPs markers in properly selected QTL regions for quality, already identified above were used. The following characters were measured: capacity expansion (ml/g), grain density (g/ml), sphericity of grains and 100 grains weight (g). In comparison the Viçosa c0 used as the reference population for the highest mean values for LD linking group found in Viçosa c2 fic (D' = 0,8911; r 2 = 0,1905) as well as to related and unrelated SNPs (D' = 0,8911, r 2 = 0,1905) . Regarding the MA significant associations (p < 0.05) were found for all traits, with thirteen associations related to the feature expandability, twenty three with the sphericity of the grains, eight with the weight of 100 grains and seventeen density of the grains. / Desequilíbrio de ligação (LD) é definido como a associação não aleatória entre alelos de diferentes locos em uma população e mapeamento associativo (MA) refere-se à associação estatística significativa entre o marcador molecular e a característica fenotípica. Os objetivos deste trabalho foram: (1) estimar o desequilíbrio de ligação em populações de milho pipoca relacionadas por ciclos de seleção utilizando marcadores SNP, (2) comparar as populações quanto ao grau de LD, (3) avaliar alterações de frequências alélicas e (4) identificar associações significativas entre marcadores e características relacionadas à qualidade do milho pipoca. No total foram avaliadas 465 amostras, sendo 354 amostras pertencentes à - populações pertencentes ao germoplasma do Programa de Melhoramento de Milho-Pipoca da Universidade Federal de Viçosa. As populações foram submetidas aos seguintes ciclos de seleção: Viçosa ciclo 1 e Beija-Flor ciclo 1, obtidas após um ciclo de seleção entre e dentro de famílias de meios-irmãos, Viçosa ciclo 4, obtida após quatro ciclos de seleção entre e dentro de famílias de meios-irmãos, Viçosa ciclo 2 famílias de irmãos completos (FIC), obtidas após dois ciclos de seleção entre e dentro de famílias de irmãos completos, Viçosa S 4, obtida por seleção de progênies S4. Foram utilizados 96 marcadores SNP devidamente selecionados em regiões de QTL pré-identificadas para qualidade. Os seguintes caracteres foram mensurados: capacidade de expansão (ml/g), densidade dos grãos (g/ml), esfericidade dos grãos e peso de 100 grãos (g). Em comparação a Viçosa c0, utilizada como população de referência os maiores valores médios de LD por grupo de ligação foram encontrados em Viçosa c2 fic r2=0,1905). Na análise de MA foram encontradas associações significativas (p < 0,05) para todas as características avaliadas, sendo treze associações relacionadas com a característica capacidade de expansão, vinte e três com a esfericidade dos grãos, oito com o peso de 100 grãos e dezessete com a densidade dos grãos.