ABSTRACT The use of longitudinal measurements is an essential practice both in Psidium guajava L. breeding and in other perennial crops in which covariance structures can be introduced to explain the form of dependence between measurements. Hence, this study aimed to analyze six covariance structures to identify one that best described the correlation between the repeated measurements in time in traits of guava full-sib families. The repeatability coefficient for each trait was estimated and the minimum number of evaluations required for estimates representing the population was determined. The work was performed based on average data of three yield-related variables from nine harvests of a guava tree population evaluated from 2011 to 2018. The best model was chosen based on the Akaike and Schwarz Bayesian information criterion. The autoregressive covariance structure best represented the dependencies among families between crops for all traits. The number of variables of fruits and total yield per plant presented repeatability estimates higher than 0.5 and may be essential traits for indirect selection of others, such as fruit mass, which had an estimated repeatability of 0.24, proving low regularity in the repetition of the character from one cycle to another. It was also possible to define four harvests as the minimum acceptable number of observations necessary on the same individual for these traits; therefore, the repetitions represented the individuals.

RESUMO: O objetivo deste trabalho foi determinar o tamanho de amostra, em número de anos, para a estimação da média de precipitação pluvial mensal em locais do Estado de Mato Grosso do Sul e verificar sua variabilidade espaço-temporal. Utilizaram-se os dados de precipitação pluvial do período de 1954 a 2013, coletados do Sistema de Informações Hidrológicas da Agência Nacional de Águas - ANA. Em cada uma das 384 séries temporais (12 meses × 32 locais), calcularam-se a média e o desvio padrão e testaram-se a aleatoriedade e a normalidade dos dados. Verificou-se a homogeneidade de variâncias entre os meses em cada local e entre os locais em cada mês. Calculou-se o tamanho de amostra em cada mês e local. O tamanho de amostra (número de anos) para a estimação da média de precipitação pluvial mensal é dependente do mês e do local. Para os meses e locais estudados, 63 anos de observações são suficientes para estimar a média de precipitação pluvial mensal, para um erro de estimação igual a 45% da média estimada, com grau de confiança de 95%.

ABSTRACT: The aim of this study was to determine the sample size, in number of years, to estimate the means monthly rainfall in locations of Mato Grosso do Sul and verify its spacetemporal variability. It was used the rainfall data for the period 1954-2013, collected from the Hydrological Information System of the National Water Agency - ANA. The means and standard deviation were calculated for each of the 384 time series (12 months x 32 locations) and the aleatory and normality data were tested. Then it was verified the homogeneity of variance among months in each locality and among locality in each month and it was determined the sample size to estimate the means monthly rainfall in each month and locality. The sample size (number of years) to estimate the means monthly rainfall is dependent on the month and locality. One concluded that 63 years of data are enough to predict the average monthly rainfall, with an estimation error equal to 45% of estimated average, with a degree confidence of 95%.