Alessandro Dal’Col Lúcio

Variância e média da massa de frutos de abobrinha-italiana em múltiplas colheitas

The variance associated to the production of plants with multiple harvests is not always homogeneous, what compromises the experimental precision. To address this issue, in this work we identified (1) the behavior of the means and variance for fruit mass in zucchini (Curcubita pepo) along harvests, between planting rows within and betweens harvests, and (2) the interference of different crop managements over these parameters. The experiment was carried out in two seasons, winter-spring (I/P) and summer-autumn (V/O), 2004/2005, using cultivar Caserta and two plastic tunnels (T1 and T2), with three 25-plant rows in each tunnel. In T1, drip irrigation was used, combined with mulching over the ridges, and less biocide spraying than in T2. In T2, sprinkler irrigation was used, placed 1,8 m height, without mulching. The Bartlett test was applied to the six planting row variances within each harvest and to the average variance of each row to check the homogeneity between harvests in each crop season. The t test was used to compare the production means in each planting row, in each harvest, in each tunnel, and also between planting rows, for plants with the same position in the tunnel. In the V/O season, variances were homogeneous in two out of the eleven harvests. In season I/P, variances were homogeneous in ten of the thirteen harvests. In both seasons, variance homogeneity was higher in the first half of the cycle. In V/O, variances in T1 were in general smaller than in T2 in the whole cycle. In both seasons there was variance heterogeneity between harvests. In V/O, significant differences were observed in six and three harvests, respectively in T1 and T2, with production means reaching 481.0 and 454.0 g plant-1 T1 and T2, respectively. In I/P, significant differences were observed in the first (T1) and fourth and fifth harvests (T2), with the means for fruit mass reaching 598.2 (T1) and 597.4 g plant-1 (T2).

Tamanho da amostra e método de amostragem para avaliação de características do pimentão em estufa plástica

Information from all plants in a row are usually collected in greenhouse experiments. This increases experimental cost, labor, time and space for collecting data from all plants and fruits. The sample size and sampling method for sweet pepper experiments in greenhouse were determined, during winter-spring of 2000 and summer-fall of 2001. The greenhouse was located at the Universidade Federal de Santa Maria, Brazil. The experiment was conducted with ten rows of 23 m length with 72 plants per row. Fresh fruit weight variances were heterogeneous among rows for each cultivation season, between the two seasons. The sample sizes estimated for the winter-spring and summer-fall seasons were, respectively, 56 and 50 plants per row in each crop with 95% of confidence.

Correlations between growth variables and the Dickson quality index in forest seedlings

This study aims to identify correlations between growth variables and the Dickson quality index in seedlings of Eucalyptus grandis and Pinus elliottii var. elliottii. The experiment was conducted in a greenhouse and the following variables were observed: stem base diameter, shoot height, number of leaves, leaf dry matter, stem base dry matter, root dry matter, shoot dry matter, total dry matter, ratio of shoot dry matter to root dry matter and ratio of shoot height to stem base diameter in E. grandis 60, 75, 90, 105 and 120 days after seedling emergence, and in P. elliottii 25, 50, 75, 100, 125, 150 and 175 days after seedling emergence. Using Pearson correlation and also path and regression analyses, correlations were analyzed between observed variables according to day after emergence and the Dickson quality index. Stem base diameter was found to have stronger correlation with days after emergence in comparison to shoot height, in both species. Root dry matter was found to have stronger correlation with the Dickson quality index. Stem base diameter was the most suitable parameter to indicate seedling quality due to its higher correlation level with the Dickson quality index. Shoot height was only effective to indicate seedling quality if analyzed together with stem base diameter. Variables relating to dry matter showed the highest correlations with the Dickson quality index (DQI), followed by stem base diameter. Conversely, number of leaves showed the poorest correlations with DQI, followed by seedling height.

Ajustes de quadrado médio do erro em ensaios de competição de cultivares de milho pelo método de Papadakis

The objective of this work was to evaluate the different ways to calculate the yield index, used as covariable for the Papadakis method, and to verify if this method is efficient to increase the experimental precision in corn (Zea mays L.) cultivars competition trials with high number of treatments. The following analysis was performed using grain yield data: mathematical model assumption, analysis of variance in the randomized complete block design (conventional analysis), and analysis of covariance in the completely random design using yield index as a covariable. The yield index covariable was estimated using five different variants of the Papadakis method. The comparisons between the conventional analysis and the Papadakis method was done with the mean square error, coefficient of variation, least significant differences of Tukey test, group numbers of Scott-Knott cluster analysis, and differentiation index of Fasoulas. Papadakis method improved the experimental precision from 10.5% to 48.1% in all different ways used to estimate index yield covariable. The four hills neighboring the reference hill was the best index to increase experimental precision.

Estimativa de parâmetros para o planejamento de experimentos com a cultura do pimentão em área restrita

The ideal size and shape of plots for green pepper experiments under protected environments was determined. Two experiments were conducted in plastic green house, in 2001, in the summer-fall and in the winter-spring season, evaluating the fruit weight. The plants were laid out in ten lines of twenty meters length, and in each line were allocated seventy plants. The estimates of the plot size and shape were obtained by the maxim curvature, variable comparison and Hatheway methods. Applying these methods we could conclude that the plot size and shape estimates are similar considering the maximum curvature and Hatheway methods and with the cultivation seasons. Each plot must have two plants long a five plants width, with a total of ten plants per plot.

Parâmetros da precisão experimental das principais culturas anuais do estado do Rio Grande do Sul

In agricultural research the experimental quality is a factor that indicates reliable results. This quality may be described by variation (CV) and precision (CP) coeficients and least significant difference (LSD) which also are used to measure experimental precision. The study main goal was to identify the theoretical distribution of statistical parameters to establish precision limits for maize, rice, soybean and wheat crops. Another objetive was to established parameters for 0experimental quality standards and identify management technics which affect their quality. It was studied 1655 experiments with cultivars: 549 of maize, 104 of rice, 480 of soybeans and 522 of wheat. The adherence hypothesis for CV, CP and LSD to normal distribution was rejected (1% level) for all studied crops. However the normaly of statistical parameters were more evident for sub-groups with same crop management and for each crop. Crop management such as plant population control, herbicide and insecticide application reduce precision for maize experiments. Herbicide application, start or band fertilization reduced the precision for rice experiments while pre-germination increase experimental precision. Start and band fertilization for soybean experiments reduced precision while herbicide and insecticide application and seed treatments increased experimental precision. The precision was increased for wheat crop experiments was increased when seed was treated and insecticides were applied. It was established limits for CV, CP and LSD to be used in experimental quality control. The later parameters were equivalent among then to measure experimental precision. However, it was recomended to use the LSD due to the facility of estimation and the economical importance.

Size and form of plots for the culture of the Italian pumpkin in plastic greenhouse

ABSTRACT: Quality control is the guaranty that experimental error is kept under acceptable levels, andthe definition of the proper size and form of experimental plots ensures acurate experimental planning.This paper aims to determine the proper plot size and shape for the culture of the Italian pumpkin inprotected environments. Two experiments were set in plastic green house in distinct crop seasons: eitherSummer-Fall or Winter-Spring season. The experiment comprised eight, 23-m long lines with 20 plantseach, and fruit weight was considered the main performance parameter. Estimates of best plots size andshape were obtained by the maximum curvature, variance comparison and Hatheway methods. The plotsize and shape varied according to the season and the ideal size and shape, according to the maximumcurvature and Hatheway methods, to the Summer-Fall and Winter-Spring seasons, were eight plants (4 ×2 plot) and four plants (2 × 2 plot), respectively.Key words: Curcubita pepo, protected environment, experiment planning, quality control

Tamanho ótimo de parcela para a cultura do feijão-vagem

With the aim of estimating the optimum plot size and verify the behavior of the experimental precision in different plot sizes and shapes to consider the production of snap beans, the following white experiments were conducted: 1) in a greenhouse during the autumn and winter; 2) in a poly-tunnel during the autumn and winter; 3) in an unprotected environment during the autumn and winter; 4) in a poly-tunnel during the spring and summer; and 5) in an unprotected environment during the spring and summer. The fresh pod mass was measured for pairs of plants. For each different plot size (X) the variation and its relation to X was estimated. The optimum plot size was estimated using the method of maximum modified curvature, and the significant minimum differences between averages were estimated using the Hathaway method. Analyze the total fresh biomass of pods reduces variability in experiments with green beans and optimum plot size recommended for this crop is 16 plants in a greenhouse for experiments and plans for 12 tunnel experiments and experiments in non-protected.

Tamanho de amostra para experimentos com feijão-de-vagem em diferentes ambientes

Aiming to estimate the sample size for the fresh weight of pods of bean pod, five experiments were performed with blank Macarrao at autumn / winter 2009 and spring / summer 2010, in greenhouse, tunnel and field. The basic units (BU) were pairs of plants, resulting in 36 per line of UB cultivation in the greenhouse, and 42BU in tunnel and field. For each row of plants in each harvest and group of crops it was estimated the mean, variance and coefficient of variation (CV%). When the variances were not heterogeneous lines, it was used for calculation the of the sample size, the CV% of the experiment, when they were heterogeneous, it was used the CV% of the line in which this was higher. It was concluded that the variability of production of fresh pods increases in adverse weather conditions. The analysis of total production enables the use of smaller sample sizes. In this condition, for a semi-amplitude of the mean confidence interval (D%) of 10 in fall / winter, it is necessary to sample in the row of plants, 28 plants in the greenhouse, 21 in the tunnel and 26 on the field. In the spring / summer for a D=10%, it was necessary to sample in the row of plants, 22 plants in tunnel cultivation and 24 on the field.

Plot size and experimental unit relationship in exploratory experiments

Quality of field experiments data dependent upon adequate experimental design. This study investigated the relationship between the size of the basic unit for exploratory experiments and the optimum plot size, and the experiment precision with potato crop. Tuber yield of 24 rows, 144 mounds, were used to arrange experimental units of one, two, three, four, six, eight and 12 mounds. Tuber yield data of different mounds were used to arrange plot sizes with different numbers of basic units. The model CV(x)=A/XB was adjusted, in which CV(x) was the coefficient of variation among plots with different numbers of basic units. Optimum plot size was estimated with the modified maximum curvature method of the function CV(x)=A/XB, allowing completely random design. Experimental precision was estimated though the Hatheway method for different experimental arrangements. Based upon the modification of the maximum curvature method, for a fixed total experimental area, experimental unit size of potato initial experiments affects optimum plot size estimations with the same experimental precision and variable number of treatments.