Interferência do tamanho de amostra no diagnóstico de multicolinearidade em análise de trilha

The objective of this work was to evaluate the interference of sample size on multicollinearity diagnosis in path analysis. From the analyses of productive traits of cherry tomato, two Pearson correlation matrices were obtained, one with severe multicollinearity and the other with weak multicollinearity. Sixty-six sample sizes were designed, and from the amplitude of the bootstrap confidence interval, it was observed that sample size interfered on multicollinearity diagnosis. When sample size was small, the imprecision of the diagnostic criteria estimates interfered with multicollinearity diagnosis in the matrix with weak multicollinearity.O objetivo deste trabalho foi avaliar o impacto do tamanho da amostra sobre o diagnóstico da multicolinearidade em análise de trilha. A partir das análises de variáveis produtivas do tomate-cereja, foram obtidas duas matrizes de correlação de Pearson, uma com multicolinearidade severa e outra com multicolinearidade fraca. Sessenta e seis tamanhos de amostra foram delineados e, a partir da amplitude do intervalo de confiança “bootstrap”, verificou-se a existência de interferência do tamanho da amostra na multicolinearidade. Quando o tamanho da amostra foi pequeno, a imprecisão das estimativas dos critérios de diagnóstico interferiu na conclusão quanto à multicolinearidade da matriz com multicolinearidade fraca

Época de colheita da cana-de-açúcar para processamento e qualidade tecnológica de açúcar mascavo

The objective of this work was to evaluate the optimal harvest time of ten genotypes of sugarcane (Saccharum officinarum) for the processing and quality of brown sugar. The experiment was carried out in a randomized complete block design in a 3x10 factorial arrangement in split plots, with three harvest times and ten sugarcane genotypes, in the state of São Paulo, Brazil. The qualitative parameters of brown sugar were evaluated by Scott-Knott’s test, at 5% probability. The harvest season in September, known as the middle of the harvest, is the most suitable for the production of brown sugar due to the higher of ºBrix values of cane, ºBrix of the broth, pol of brown sugar, and total reducing sugars in this period. The harvesting of the sugarcane genotypes in June-July is the most favorable for the production of brown sugar for the color characteristics a*, b*, L*, and chroma; however, it is also the period of production of brown sugar with a lower sugar content. The third harvest season (November) is the least recommended for brown sugar production due to the higher fiber and purity values. The most suitable genotype for brown sugar production and quality is 'IACSP04-704'.O objetivo deste trabalho foi avaliar a época ideal de colheita de dez genótipos de cana-de-açúcar (Saccharum officinarum) para o processamento e a qualidade de açúcar mascavo. O experimento foi realizado em delineamento de blocos ao acaso, em arranjo fatorial 3x10, em parcelas subdivididas, com três épocas de colheita e dez genótipos de cana-de-açúcar, no estado de São Paulo, Brasil. Os parâmetros qualitativos de açúcar mascavo foram avaliados pelo teste de Scott-Knott, a 5% de probabilidade. A época de colheita em setembro, conhecida como meio de safra, é a mais adequada para a produção de açúcar mascavo, em razão dos maiores valores de ºBrix da cana, ºBrix do caldo, valor pol do mascavo e açúcares totais redutores nesse período. A colheita dos genótipos de cana-de-açúcar em junho-julho é a mais favorável para a produção de açúcar mascavo quanto às características de coloração a*, b*, L* e croma; no entanto, é também o período de produção de açúcar mascavo com menores teores de açúcar. A terceira época de colheita (novembro) é a menos recomenda para a produção de açúcar mascavo, em razão dos maiores valores de fibra e pureza. O genótipo mais adequado para a produção e a qualidade de açúcar mascavo é o 'IACSP04-704'

Uniformity trials size for estimating cherry tomato plot size

ABSTRACT The aim of this study was to determine how the size of the uniformity trial influences the estimation of cherry tomato plot size. The size of plot required to evaluate the mean length of fruit per plant, mean fruit width per plant, mean fruit weight per plant, number of bunches per plant, number of fruits per bunch, number of fruits per plant and total weight of fruits per plant was estimated in uniformity trials in two greenhouses: large (250 m²) and small (200 m²). In each greenhouse and row, and for each variable, 3000 plot size estimates were obtained by resampling and used to determine of 97.5 and 2.5% percentiles. Each row needs to be treated as a specific uniformity trial because of significant row variability. It is recommended that uniformity trials are carried out on 35 plants in the large greenhouse and 23 plants in the small greenhouse in order to estimate cherry tomato production variables at a confidence interval of 30% of the mean

Linear relationships between cherry tomato traits

ABSTRACT: The objective of this study was to identify the linear relationship between cherry tomato yield components. Two uniformity trials, without treatments, were conducted on Lilli cherry tomato plants in a plastic greenhouse during the 2014 spring/summer season, with the plants in two stems. Variables observed for each plant were mean fruit length, mean fruit width, mean fruit weight, number of bunches, number of fruits per bunch, total number of fruits, and total fruit weight; a Pearson's correlation matrix was used to estimate the relationship between the variables. Path analysis was then performed considering total fruit weight as the main variable and the remaining variables as explanatory. Due to the severe multicollinearity, the variable 'number of fruits per bunch' was eliminated. Pearson's correlation coefficients were significant between explanatory and main variables. Mean fruit weight has a low cause-and-effect relationship with the total weight of fruits produced. A low cause-and-effect relationship was also observed between number of fruits and number of bunches. Cherry tomato productivity is directly related to the number of fruits per plant

SAMPLE SIZE FOR ASSESS THE LEAF BLAST SEVERITY IN EXPERIMENTS WITH IRRIGATED RICE

The aim of this study was to determine the sample size needed to assess the severity of leaf blast in rice in experiments with different fungicide treatments. The severity and the area under the disease progress curve data of three chemical disease control treatments carried out in Rio Grande do Sul, were used in the study. Analysis of variance was performed to verify whether the severity of the disease differed between treatments. The spread of disease was was also found to be different between treatments and assessments, using the variance/mean ratio and Morisita index. The spatial distribution of the disease among the treatments and during the evaluations is important for the choice of the equation used to calculate the sample size. The spatial distribution of the disease was not the same across the experiments, and it varied between treatments and evaluations. Thus, we decided to use a formula that was not associated with distributions to indicate the spatial distribution (negative binomial or Poisson) of the disease in the field. The sample size to estimate the average of rice leaf blast severity varied between treatments and evaluations. The area under the disease progress curve is necessary to be determined to reduce the number of samples needed. Thus, it is recommended to assess 293 sheets to estimate severity, and 63 to estimate AUDPC at 20% error

Sample size for estimation of the Pearson correlation coefficient in cherry tomato tests

ABSTRACT: The aim of this study was to determine the required sample size for estimation of the Pearson coefficient of correlation between cherry tomato variables. Two uniformity tests were set up in a protected environment in the spring/summer of 2014. The observed variables in each plant were mean fruit length, mean fruit width, mean fruit weight, number of bunches, number of fruits per bunch, number of fruits, and total weight of fruits, with calculation of the Pearson correlation matrix between them. Sixty eight sample sizes were planned for one greenhouse and 48 for another, with the initial sample size of 10 plants, and the others were obtained by adding five plants. For each planned sample size, 3000 estimates of the Pearson correlation coefficient were obtained through bootstrap re-samplings with replacement. The sample size for each correlation coefficient was determined when the 95% confidence interval amplitude value was less than or equal to 0.4. Obtaining estimates of the Pearson correlation coefficient with high precision is difficult for parameters with a weak linear relation. Accordingly, a larger sample size is necessary to estimate them. Linear relations involving variables dealing with size and number of fruits per plant have less precision. To estimate the coefficient of correlation between productivity variables of cherry tomato, with a confidence interval of 95% equal to 0.4, it is necessary to sample 275 plants in a 250m² greenhouse, and 200 plants in a 200m² greenhouse

Aplicação aérea de fungicidas na cultura do arroz irrigado com diferentes bicos de pulverização Aerial fungicide application on irrigated lowland rice with varying spraying nozzles

Na safra agrícola 2007/2008, foi realizado um estudo com o objetivo de avaliar a deposição e penetração de gotas através de cartões hidrossensíveis e análise cromatográfica. Para isso, utilizaram-se o bico eletrostático, bico hidráulico e atomizadores rotativos de discos com diferentes volumes de calda. As pulverizações foram realizadas no estádio R3 da cultura, com aeronave Ipanema EMB-202, aplicando-se fungicida trifloxistrobina + propiconazole. Através da leitura de cartões hidrossensíveis, determinou-se a densidade de gotas, o diâmetro médio numérico, diâmetro médio volumétrico, amplitude relativa e a penetração de gotas no dossel (%). Também foi utilizada a análise cromatográfica para determinar a penetração do produto no alvo biológico. O bico hidráulico, com taxa de aplicação de 20L ha-1 e 30L ha-1, e o bico eletrostático, com taxa de aplicação de 10L ha-1, obtiveram maior densidade de gotas no terço superior. O uso de atomizadores rotativos de disco com volume de calda de 15L ha-1 apresentou maior densidade de gotas no terço médio e inferior. Para diâmetro médio volumétrico, os bicos eletrostáticos juntamente com os atomizadores rotativos de discos apresentaram os menores valores. A maior homogeneidade de gotas no terço superior foi obtida com atomizadores rotativos de disco com taxa de aplicação de 6L ha-1 e 10L ha-¹. A análise cromatográfica mostrou que a maior quantidade de produto foi retida com bicos eletrostáticos com taxa de aplicação de 10L ha- ¹ no extrato inferior da planta.In the harvest year of 2007/2008 a study was carried to evaluate the droplets deposition and penetration throughout water sensible cards and gas chromatographic analysis. Were used the hydraulic nozzle, electrostatic nozzle and rotary-disk atomizer spraying systems, with different volumes of spray solution. Aerial applications were performed at R3 stage using the aircraft Ipanema EMB-202 and the fungicide trifloxystrobin + propiconazole. Throughout the lection of the water sensible cards was determinate the droplet density, the medium numeric diameter, the medium volumetric diameter, the relative amplitude and the percentage of droplet penetration in the canopy. Chromatographic analysis was also performed to determinate the fungicide penetration into the biological target. The pulverization systems hydraulic nozzle 20L ha-1 and 30L ha-1 and the electrostatic system 10L ha-1 demonstrated higher droplet density in the upper third. The rotary-disk atomizer 15L ha-1 showed higher droplet density in the mid and low third. To the medium volumetric diameter, the electrostatic nozzles and the rotary-disk atomizer showed the lowest values. The higher homogeneity in the upper third was attained with rotary-disk atomizer at the pulverization rates of 6L ha-1 and 10L ha-1. The chromatographic analysis showed that the higher quantity of product retention was obtained with the electrostatic system at the pulverization rate of 10L ha-1 in the lower plant extract