Measurements of experimental precision and number of replicates in rice genotype trials

Abstract

The objective of this work was to evaluate the appropriateness of the statistics selective accuracy
and F‑test value for genotype, as measurements of the experimental precision degree, and to determine the number of measurements (replicates) necessary to predict the performance of irrigated rice (Oryza sativa) genotypes. Grain yield data from 175 genotype competition trials of rice irrigated by flooding were used. The trials were carried out in Rio Grande do Sul State, Brazil, from 1998 to 2011. The experimental design was a randomized complete block with four replicates and the number of genotypes between 5 and 36. Correlation and path analysis were performed, and the frequency of trials was calculated in each experimental precision class. To predict true genotypic values, the repeatability coefficients were estimated and the number of needed replicates was calculated. The statistics selective accuracy and F‑test value for genotype are appropriate to
evaluate the experimental precision of irrigated rice genotype trials. Trials with five replicates can identify
superior irrigated rice genotypes, with 82% accuracy of the true prognostic value.