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Each genotype was exposed to controlled PHS conditions for evaluation of susceptibility or tolerance to sprouting, falling number, kernel color, test weight, and yield. The 24 genotypes were grown in replicated trials at three locations over three years, all data subjected to an analysis of variance. Over three years the genotypes were rated for visual PHS using a 1 to 9 scale, with 1 equivalent to no visual PHS and 9 equivalent to maximum visual PHS. The red genotypes exhibited a higher tolerance to PHS than white genotypes with a mean PHS score of 4.46 compared with 5.16 for white genotypes. Not all the white genotypes were equally susceptible to PHS or more susceptible than the red genotypes, suggesting that not all seed dormancy is linked to the kernel color genes.

Several seemingly conflicting sets of data have been reported on the regenerative capacity of central noradrenergic neurons, following transection of the ascending noradrenergic fiber tract in neonatal rats (Iacovitti et al., Dev Brain Res 1: 21-33, 1981; Jonsson and Sachs, Brain Res Bull 9: 641-650, 1982). In order to more fully investigate changes in noradrenergic neurons in the brain after such a transection, rats were lesioned at various times after birth, sometimes in conjunction with administration of the neurotoxin, 6-hydroxydopa (6-OHDOPA). Animals were sacrifced at 7, 10, 14, 28, 42 or 56 days after birth, in order to assess the pattern of noradrenergic neuronal damage, as well as the recovery rate. Dorsal bundle lesions were associated with neocortical and hippocampal hypoinnervation by noradrenergic fibers, and sprouting of a collateral fiber group, with production of noradrenergic hyperinnervation of the cerebellum and pons-medulla. Recovery of the norepinephrine (NE) content to control levels occurred in the neocortex at 8 weeks, when the dorsal bundle was lesioned at birth. When the lesion was produced at a later time (3 days or 5 days after birth), less recovery in the neocortex and hippocampus was found. Histofluorescent fiber number, as observed with a glyoxylic acid method, correlated with NE changes. It appears that 6-OHDOPA (20 μg/g IP) does not modify long-term recovery from a dorsal bundle lesion, when rats are co-treated at 3 days after birth. However, the length of the proximal noradrenergic fiber stump may be an important factor affecting the capacity for recovery from injury. These results suggest that a shorter fiber stump, as produced with a dorsal bundle lesion at the level of the pons, may be associated with a greater degree of recovery from injury. Also, the younger the rat at the time of injury, the greater appears to be the capacity for regeneration. These results demonstrate that regeneration can occur in one part of the brain without modification of a collateral hyperinnervation of a different part of the brain. Therefore, our findings discount a programming of central noradrenergic fibers to express a specific number of nerve terminal arborizations, (i.e., the "pruning hypothesis").

Malts prepared from sorghum and cowpeas that was germinated at 25°C for 0, 1, 2 or 3 days and dried at 60°C for either 2.5, 5, 7.5 and 10 hours, were evaluated for α-amylase, β-amylase and endo-(1,3)(1,4)-β-D-glucanase activity. Germination had a highly significant effect on enzyme activity (P < 0.01). However, cowpea endo-(1,3)(1,4)-β-D-glucanase was not significantly affected by the combined action of germination and drying. β-Amylase was not detected in any of the samples of this experiment. Further analysis using Duncan’s Multiple Range Test, indicated that there was no significant difference in α-amylase activity in samples dried between 5 to 10 hours. Compared to α-amylase, sorghum and cowpea samples had low endo-(1,3)(1,4)-β-D-glucanase activity. / Master of Science

Three cotton (Gossypium hirsutum L.) germplasms (DP62, 84027, and 84033) were used to investigate the physiology of salt tolerance. Lines 84027 and 84033 were developed from the parental line DP62 and showed superior vigor under varying NaCl conditions (0.5 to 2.0 M) during germination and emergence. Proline levels increased in the leaves of all germplasms in response to increasing salinity. Varietal differences in proline levels did not reflect their variation in salt tolerance. Several physiological characteristics were also evaluated under non-saline condition in the greenhouse. There were no significant differences among germplasm sources for all parameters measured. However, salinity reduced transpiration rate, increased leaf diffusive resistance and leaf temperature for all lines. Ribosomal-RNA levels in all germplasms were evaluated after seeds were stressed for 24 hrs in various concentrations of NaCl and then germinated under normal conditions for 72 hrs. Ribosomal-RNA levels were inversely related to salt concentrations. Line 84033 followed by line 84027 had highest ribosomal-RNA content than the parental line DP62 when averaged over the four salt concentrations. Sodium content (ppm/g FW) and Cl⁻ content (ppm/g FW) were evaluated in microsomal and cell walls fractions as well as a cytoplasmic fraction which consisted of vacuoles, mitochondria, and plastids. The Cl⁻ ion exhibited a greater consistency in a concentration shift from one fraction to another as a function of time than did the Na⁺ ion. As a result, there may be a correlation between the drop in ribosomal-RNA and the amount of Cl⁻ in the microsomal fraction. Other parameters measured in the germinating seed were soluble protein (globulin), insoluble proteins (prolamin and glutelin) and fiber percentage. Variations within the germplasms were shown to exist. This study shows that even among lines that have been selected for salt tolerance from a single variety, the possibility exists that each of these lines may have a different mechanism to cope with salt stress.

Para otimizar o processo de plantio mecanizado, faz-se necessário o uso de toletes menores, que possibilitem a adaptação dos mesmos às máquinas agrícolas. O objetivo do estudo foi avaliar a influência do tamanho e da posição do propágulo no colmo da cana-de-açúcar e da aplicação de biorreguladores (ethephon) e bioativadores (cianamida hidrogenada) no desenvolvimento inicial da planta. Foram realizados 8 experimentos no Departamento de Produção Vegetal da Escola Superior de Agricultura \"Luiz de Queiroz\" - ESALQ/USP, município de Piracicaba - SP. Quatro dos experimentos foram realizados em ambiente aberto, em área experimental, e outros quatro em ambiente protegido, casa de vegetação. Foram utilizadas duas variedades nos experimentos, RB966928 e CTC15. Os propágulos foram seccionados de acordo a sua posição no colmo da cana-de-açúcar, apical, mediana e basal. Seu tamanho foi variável devido à diferença de nós e entrenós ao longo de um mesmo colmo. Foram realizadas avaliações semanais das plantas, sendo coletados dados de altura, diâmetro, e número de brotos. O delineamento utilizado foi o de blocos ao acaso, com 4 repetições por tratamento, distribuídas em 4 blocos, sendo que cada sulco correspondeu a um bloco. Os dados numéricos obtidos de número de brotos, altura e diâmetro de plantas foram submetidos à análise de variância e, quando o F foi significativo à 5%, as médias foram submetidas ao Teste de Tukey. As análises estatísticas foram realizadas com o software SAS. Verificou-se que a posição dos propágulos no colmo de cana-de-açúcar influencia a brotação; os propágulos da posição apical são superiores em brotação aos da posição basal; a aplicação do biorregulador ethephon em propágulos de cana-de-açúcar estimula a brotação e prejudica o desenvolvimento inicial em altura dos brotos; a aplicação do bioestimulante cianamida hidrogenada não influencia a brotação de propágulos de cana-de-açúcar; os propágulos com duas gemas apresentam melhor desempenho em brotação e desenvolvimento inicial dos brotos do que propágulos com apenas uma gema. / To achieve improves on sugarcane mechanical plantation, the use of smaller stem pieces becomes necessary, which enables their adaptation to agricultural machinery. The aim of this study was to evalue the influence of size and position of stem on sugarcane stalk and the application of ethephon and hydrogen cyanamide on plant initial development. There were performed eight experiments in Department of Vegetal Production from Escola Superior de Agricultura \"Luiz de Queiroz\" - ESALQ/USP, Piracicaba, São Paulo. Four experiments were performed on field, in experimental area, and four other were performed in greenhouse. There were utilized two cultivars, RB966928 and CTC15. The stems were cut according their position in sugarcane stalk, apical, mean and basal. Their size were variable, due the difference of node and internode along a same stalk. There were performed weekly evaluation of the plants, of which was collected height, diameter and shoots number. The statistical design was randomized blocks, with four replicates by treatment, in four blocks, wherein each planting furrow corresponding to a block. Numerical data obtained by shooting, plant height and diameter were submitted by analysis of variance by F test and compared by Tukey test at 5% of probability, using SAS software. There were verified that stem position influences sprouting; apical stem have a superior number of shoots than basal stem; ethephon application in sugarcane stems stimulates sprouting and damages initial development in height of plants; hydrogen cyanamide application does not influences stem shooting; stems with two buds present better performance in sprouting and initial development of shoots than stems with one bud.

Para otimizar o processo de plantio mecanizado, faz-se necessário o uso de toletes menores, que possibilitem a adaptação dos mesmos às máquinas agrícolas. O objetivo do estudo foi avaliar a influência do tamanho e da posição do propágulo no colmo da cana-de-açúcar e da aplicação de biorreguladores (ethephon) e bioativadores (cianamida hidrogenada) no desenvolvimento inicial da planta. Foram realizados 8 experimentos no Departamento de Produção Vegetal da Escola Superior de Agricultura \"Luiz de Queiroz\" - ESALQ/USP, município de Piracicaba - SP. Quatro dos experimentos foram realizados em ambiente aberto, em área experimental, e outros quatro em ambiente protegido, casa de vegetação. Foram utilizadas duas variedades nos experimentos, RB966928 e CTC15. Os propágulos foram seccionados de acordo a sua posição no colmo da cana-de-açúcar, apical, mediana e basal. Seu tamanho foi variável devido à diferença de nós e entrenós ao longo de um mesmo colmo. Foram realizadas avaliações semanais das plantas, sendo coletados dados de altura, diâmetro, e número de brotos. O delineamento utilizado foi o de blocos ao acaso, com 4 repetições por tratamento, distribuídas em 4 blocos, sendo que cada sulco correspondeu a um bloco. Os dados numéricos obtidos de número de brotos, altura e diâmetro de plantas foram submetidos à análise de variância e, quando o F foi significativo à 5%, as médias foram submetidas ao Teste de Tukey. As análises estatísticas foram realizadas com o software SAS. Verificou-se que a posição dos propágulos no colmo de cana-de-açúcar influencia a brotação; os propágulos da posição apical são superiores em brotação aos da posição basal; a aplicação do biorregulador ethephon em propágulos de cana-de-açúcar estimula a brotação e prejudica o desenvolvimento inicial em altura dos brotos; a aplicação do bioestimulante cianamida hidrogenada não influencia a brotação de propágulos de cana-de-açúcar; os propágulos com duas gemas apresentam melhor desempenho em brotação e desenvolvimento inicial dos brotos do que propágulos com apenas uma gema. / To achieve improves on sugarcane mechanical plantation, the use of smaller stem pieces becomes necessary, which enables their adaptation to agricultural machinery. The aim of this study was to evalue the influence of size and position of stem on sugarcane stalk and the application of ethephon and hydrogen cyanamide on plant initial development. There were performed eight experiments in Department of Vegetal Production from Escola Superior de Agricultura \"Luiz de Queiroz\" - ESALQ/USP, Piracicaba, São Paulo. Four experiments were performed on field, in experimental area, and four other were performed in greenhouse. There were utilized two cultivars, RB966928 and CTC15. The stems were cut according their position in sugarcane stalk, apical, mean and basal. Their size were variable, due the difference of node and internode along a same stalk. There were performed weekly evaluation of the plants, of which was collected height, diameter and shoots number. The statistical design was randomized blocks, with four replicates by treatment, in four blocks, wherein each planting furrow corresponding to a block. Numerical data obtained by shooting, plant height and diameter were submitted by analysis of variance by F test and compared by Tukey test at 5% of probability, using SAS software. There were verified that stem position influences sprouting; apical stem have a superior number of shoots than basal stem; ethephon application in sugarcane stems stimulates sprouting and damages initial development in height of plants; hydrogen cyanamide application does not influences stem shooting; stems with two buds present better performance in sprouting and initial development of shoots than stems with one bud.

Pre-harvest sprouting (PHS) in bread wheat (<i>Triticum aestivum</i> L.) is one of the major abiotic constraints influencing the production of high quality grain. The flour milled from sprouted wheat grains has increased Ñ-amylase activity as compared to non-sprouted grain. PHS negatively affects the properties of flour with deleterious effects on bread and noodle quality. White-grained wheat is generally more susceptible to PHS damage than red-grained wheat. The objectives of this study were to identify a suitable method for phenotyping PHS resistance and to identify PHS resistance genomic regions and markers that could be used for marker-assisted selection in wheat improvement programs. A doubled haploid (DH) mapping population from a cross between two white-grained spring wheat genotypes, Argent (non-dormant) and W98616 (dormant) was used in this study. Forty DH lines (20 dormant and 20 non-dormant) were evaluated for germination frequency, Falling Number, and Ñ-amylase activity in dry and water-imbibed seeds and spikes. The germination test was the most reliable method for measurement of PHS resistance, whereas the Falling Number and Ñ-amylase activity in dry harvested seeds could not be correlated to dormancy levels. However, a positive association (r = 0.60***) was detected between germination frequency and Ñ-amylase activity in imbibed seeds. To identify the genomic regions associated with PHS resistance, a genetic linkage map with a total genome coverage of 2,577 cM was developed. The map was constructed from 913 scored markers (356 SSR, 290 AFLP, 258 DArT and 9 EST) with an average marker density of 3.7 cM/marker. Five genomic regions on chromosomes 1A, 3A, 4A, 7A and 7D were associated with PHS resistance by interval mapping and all regions were contributed by the dormant parent W98616. A total of 60 Canadian wheat cultivars and experimental lines were screened with three SSR markers, DuPw004, barc170 and wmc650, located under the major quantitative trait locus (QTL) on chromosome 4A. The SSR markers explained 60-75% of the total variation in germination frequency among different wheat genotypes. By using the DuPw004 marker in marker-assisted back crossing, the population size in the BC1F1 and BC2F1 generations were reduced by 41% and 59%, respectively. Thus, the 4A QTL markers have been proven useful for marker-assisted selection of PHS resistance for wheat improvement.

Pre-harvest sprouting (PHS) in bread wheat (<i>Triticum aestivum</i> L.) is one of the major abiotic constraints influencing the production of high quality grain. The flour milled from sprouted wheat grains has increased Ñ-amylase activity as compared to non-sprouted grain. PHS negatively affects the properties of flour with deleterious effects on bread and noodle quality. White-grained wheat is generally more susceptible to PHS damage than red-grained wheat. The objectives of this study were to identify a suitable method for phenotyping PHS resistance and to identify PHS resistance genomic regions and markers that could be used for marker-assisted selection in wheat improvement programs. A doubled haploid (DH) mapping population from a cross between two white-grained spring wheat genotypes, Argent (non-dormant) and W98616 (dormant) was used in this study. Forty DH lines (20 dormant and 20 non-dormant) were evaluated for germination frequency, Falling Number, and Ñ-amylase activity in dry and water-imbibed seeds and spikes. The germination test was the most reliable method for measurement of PHS resistance, whereas the Falling Number and Ñ-amylase activity in dry harvested seeds could not be correlated to dormancy levels. However, a positive association (r = 0.60***) was detected between germination frequency and Ñ-amylase activity in imbibed seeds. To identify the genomic regions associated with PHS resistance, a genetic linkage map with a total genome coverage of 2,577 cM was developed. The map was constructed from 913 scored markers (356 SSR, 290 AFLP, 258 DArT and 9 EST) with an average marker density of 3.7 cM/marker. Five genomic regions on chromosomes 1A, 3A, 4A, 7A and 7D were associated with PHS resistance by interval mapping and all regions were contributed by the dormant parent W98616. A total of 60 Canadian wheat cultivars and experimental lines were screened with three SSR markers, DuPw004, barc170 and wmc650, located under the major quantitative trait locus (QTL) on chromosome 4A. The SSR markers explained 60-75% of the total variation in germination frequency among different wheat genotypes. By using the DuPw004 marker in marker-assisted back crossing, the population size in the BC1F1 and BC2F1 generations were reduced by 41% and 59%, respectively. Thus, the 4A QTL markers have been proven useful for marker-assisted selection of PHS resistance for wheat improvement.