Sidinei José Lopes

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).

Variabilidade da produção de frutos de pimentão em estufa plástica

The plastic greenhouses are considered an homogeneous environment, however, that affirmative is not tested, because production variations exist among plants, influenced by several external factors. There is a lack of information related to techniques of experimental designing in these environments. Experiments were installed in the Crop Science Department/UFSM with the culture of chili in plastic greenhouse in two seasonal seasons, in order to study the variability of the production around the average, for each harvest and in the total yield, in different plot size. With the variances homogeneity test, for each harvest and total yield, the dispersion on the production around the average, it was verified that there is a high heterogeneity in the distribution of the production among the experimental plots in protected chili culture, and that plots of 14 plants in the line had reduced the variations of soil. The randomized blocks design in the line is adequate for these environments.

Técnicas experimentais para tomateiro tipo salada sob estufas plásticas

An uniformity trial was carried out with tomate plants grown in a plastic greenhouse with an area of 24m x 12m. The total fruit yield of salad tomato cv. Monte Carlo was evaluated during 11 separat harvest. The basic plot was planted with three plants in the same row. The plants were grown in distances of 0.3m in the same row and by 1,0m between rows. All 24 plots were allocated in ten different rows. The results demonstrate that the completely randomized were more adequate with plots smaller than 18 plants in the same row. The yield evaluation in experiments with different traits using a same cultivar in plastic greenhouse should be conducted up to 30% of total yield. This is importam for more experimental precision and budged economy and time. Results showed that the minimal significance difference varies after 30% of the total yield, was harvested for three, nine and eighteen plants in each plot.

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.

A precisão experimental para diferentes manejos na cultura do milho

The effects of weed control procedures, fertilizer and seed distribution uniformity, and young plant protection to insects over the experimental error were studied. The management procedures were organized in three experiments using a completely randomized design. Each replication of the management procedure was made by 6 lines of 5m using a short-day com cultivar. The weed control, made by herbicides or manual control did not present significam difference in the experimental error. The evaluation of the experimental error of the more uniform fertilizer distribution was smaller than the desuniform distribution. The line seed distribution, done by hand and not with the same distance, caused a smaller experimental error for grain yield and final population than the line seed distribution with the same distance.

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.

Transformações de dados em experimentos com abobrinha italiana em ambiente protegido

The interest in horticulture is the production of marketable fruit. In such experiments , phytomass and the number of fruits are commonly measured variables. However, these variables have a particular characteristic related to their absence or presence at harvest time. This attribute is represented by zero values for these variables, generating some variability and affecting the variance analysis. This work aimed to define an appropriate data transformation for the variables observed in experiments with the zucchini culture, realized in protected environment, designed to stabilize the variability values generated by the presence of zeros in harvest multiple fruit. The analysis was based on experiments with the zucchini culture ,using the family of the Box-Cox transformation, with an adaptation made by YAMAMURA (1999). It was concluded that for experiments with zucchini, assessing the phytomass and number of fruits, the square square root transformation is indicated. The same was observed with the reduction in variability and normal errors, observed in all experiments. The use of the method was not efficient to make the variances homocedastic.

Variação temporal da produção de pimentão influenciada pela posição e características morfológicas das plantas em ambiente protegido

Temporal variation of the production of peppers affected by plants position and morphologic characteristics of protected crop We evaluated the effect of plant position inside a plastic greenhouse on the morphologic and production characteristics that most contribute in the increase of variability of fruit production between harvests in plastic greenhouses. The experiments were conducted during the summer/fall and winter/spring seasons, of 2002 and 2003, respectively. Pearson correlation coefficient and path analysis between morphologic characteristics, the dimension of the fruits and its respective location inside plastic greenhouse were analyzed. The farther the plants were located from the extremities of the cultivation area, resulted in less prejudiced production than those located in the central part of the area. The production variability among harvests is directly related to the weight of fruits.

Índice de heterogeneidade, coeficiente de variação e tamanho ótimo de parcela em batata

ABSTRACT This research was aimed at evaluating therelationship between one plot coefficient variation andheterogeneity index with the optimal potato plot size. Tuberyield data was gotten from 12 potato homogeneity trials. Eachtrial had 12 rows and 24 hills, from which 18 plot sizes, differingin row and hill numbers, were designed. The functions CV(x)=A/X B and VU(x)=V1/X b were adjusted, where X is the plot size innumber of basic units (BU), CV(x) is the coefficient of variationbetween plots with X BU, and VU(x) is the BU variation betweenplots with X BU. Optimal plot size estimated by three differentmethods and the results were correlated with the parameterestimations of the above two functions. Based upon path analysis,the variation coefficient between plots of the basic unit affectsmore the estimation of optimal plot size than the heterogeneityindex in potato uniformity trials. Key words: Solanum tuberosum L., heterogeneity index,experimental design, experimental precision . INTRODUCAO

Sample size for single, double and thee-way hybrid corn ear traits

O uso dos tamanhos de amostras adequados nas unidades experimentais melhora a eficiencia da pesquisa. Foi conduzido um experimento no ano agricola 2004/2005 em Santa Maria, Rio Grande do Sul, com o objetivo de estimar o tamanho de amostra para o comprimento de espiga, o diâmetro de espiga e de sabugo, o peso da espiga, dos graos por espiga, do sabugo e de 100 graos, o numero de fileiras de graos por espiga, o numero de graos por espiga e o comprimento dos graos de dois hibridos simples (P30F33 e P Flex), dois hibridos triplos (AG8021 e DG501) e dois hibridos duplos (AG2060 e DKB701) de milho. Para uma precisao de 5% (D5), caracteristicas de peso (peso de espiga despalhada, de graos, de sabugo e de 100 graos) podem ser amostradas com 21 espigas, caracteristicas de tamanho (comprimento de espiga e de grao, diâmetro de espiga e de sabugo) com oito espigas, e dados de contagem (numero de graos e de fileiras) com 13 espigas. O tamanho de amostra e variavel em funcao da caracteristica da espiga e do tipo de hibrido: simples, triplo ou duplo. A variabilidade genetica existente entre os hibridos de milho, na forma crescente: simples, triplo e duplo, nao reflete na mesma ordem no tamanho de amostra de caracteres da espiga.