Sampling sufficiency to estimate the mean productive traits of buckwheat

Abstract

The objective of this work was to determine the sample size (number of plants) necessary to estimate the mean productive traits of buckwheat (Fagopyrum esculentum), cultivars IPR91-Baili and IPR92-Altar, in the vegetative and flowering stages of the crop. Twenty-one uniformity trials were conducted for each cultivar (IPR91-Baili and IPR92-Altar). Six productive traits (leaf fresh matter, stem fresh matter, shoot fresh matter, leaf dry matter, stem dry matter and shoot dry matter) were evaluated in 2280 plants of each cultivar (IPR91-Baili and IPR92-Altar). Kolmogorov-Smirnov normality test was performed. Measures of central tendency, variability and skewness and were calculated. The sample size was calculated to estimate the mean for six traits, with estimation errors (semi-amplitudes of the 95% confidence interval) equal to 5%, 10%, 15% and 20% of the mean. There is variability in sample size between productive traits, cultivars and phenological stages of buckwheat. In an experiment to estimate the mean of these six traits of buckwheat, cultivars IPR91-Baili and IPR92-Altar, in the vegetative and flowering stages, with a maximum error of 20% of the mean at a 95% confidence interval, 80 plants per treatment are needed.