ABSTRACT:
This study aimed to estimate the coefficients of repeatability (r), determination or degree of predictability (R2) of clones characteristics of wine grapes varities, and determine the number of measurements required, capable to provide levels of certainty (80, 90 and 95%) of the real prediction l value of individuals for each character. The study was conducted from average data of eight characteristics from two experiments on the behavior of clones from two grape varieties, evaluated between the years 1989 and 1992. Based on the average of two experiments of each harvest, it was obtained estimates of the repeatability coefficient (
) and the coefficient of determination or degree of predictability (R2) for all traits. In the estimation of the repeatability coefficient, the method of analysis of variance was used. Coefficient of repeatability obtained for the two varieties have values very similar magnitude. Repeatability estimates for the eight characteristics are superior to 0.60, demonstrating constancy of clones performance in several crops and reliable genotypic discrimination more than 80%. The use of three crops is suitable for the selection to be accomplished with predictability of the real value of above 80% genotype.
Key words:
improvement; variability; clonal selection; Vitis vinifera
