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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.

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.

RESUMO O objetivo deste estudo foi avaliar a produção de fi tomassa e óleo essencial da M. offi cinalis L. com lâminas de irrigação no Norte de Minas Gerais como medidas de uso racional da água. O delineamento experimental utilizado foi o inteiramente ao acaso em parcelas subdivididas no tempo, com seis tratamentos defi nidos pelas lâminas de irrigação (T1=0,50xET0; T2=0,75xET0; T3=1,0xET0; T4=1,25xET0; T5=1,5xET0 e T6=1,75xETO) ABSTRACT The objective of this study has been to evaluate the essential oil production of Melissa offi cinalis L. with irrigation blade in the North of Minas Gerais as a measure of water rational use. The experimental design has been completely randomized in subdivided plots in the time with six treatments, defi ned by irrigation blade (T1=0,50xET0; T2=0,75xET0; T3=1,0xET0; T4=1,25xET0; T5=1,5xET0 e T6=1,75 x ETO), and four replications. The study has been conducted at the micro lysimeter. Based on regression analysis, it has been observed that the fi tomass production and growth was infl uenced by water availability. The production and content of the essential oil are inversely proportional to the increase in the irrigation blade. The production of biomass has been obtained from the smaller blade and the evaluation times did not infl uenciate on their blades.

The plot size estimation is based on uniformity trials, however little is known about and how the size of uniformity trial affects the estimate of the plot size. That way, the aim of this study was to determine the influence of uniformity trial size on the estimation of plot size in the eggplant crop. Two uniformity trials were performed with the eggplant culture in a plastic tunnel. The fresh mass of fruit and number of fruits were assessed in six harvests, with a seven-day interval between harvests. For each trial (Tunnel 1 and 2), 25 uniformity trials of different sizes were simulated (3, 4, 5, … 28 BEU) per harvest and harvest row (individual and grouped) since they presented heteroscedasticity. For each planned uniformity trial, bootstrap procedure was used to estimate 3,000 plot sizes by the maximum coefficient of variation curvature method. The mean and 95% confidence interval width was calculated by the difference between the 97.5th and 2.5th percentiles. The AIC95% and plot size averages were higher in individual harvests than grouped harvests. As the size of the simulated uniformity trial increased, it was verified a reduction of the AIC95% of the plot size. However, the mean plot size did not change with increasing uniformity trial size. In this way, it is possible to state that the size of the uniformity trial affects accuracy the plot size estimation because trials with few numbers of basic experimental units present high experimental variability and inaccurate estimates.

This research's aims were to evaluate the mixture ratios of P fertilizers in irrigated corn yield in two seasons as well as evaluate the capacity of Resin and Mehlich 1 extractors to predict the P availability under field conditions in two soils: Hapludults and Oxisol. In the first crop, the experimental design was randomized block with four replications where two P sources, Triple Superphosphate (TSP) and Daoui Natural Phosphate (DNP), were tested in four rations (100%:0%; 67%:33%; 33%:67%; 0%:100%). The second planting was carried out in a similar manner, with some modifications to verify the residual effect of the fertilizers. DNP provided lower productivity and leaf P levels when compared to TSP in the first year but the DNP contributed with a higher residual effect through the test conditions. DNP fertilization provided higher residual effect in Hapludults than in Oxisol. Only Resin extractor, in Oxisol without TSP application in the second cultivation, was efficient in estimating the availability of P to the corn plants in the experiment conditions. In the experiment conditions, DNP provided productivity and leaf P levels similar to Triple Superphosphate in the first year and its residual effect is highly dependent on the soil type.