Number of replicates and experimental precision statistics in corn

Abstract

The objective of this work was to evaluate the influence of the number of replicates on experimental precision in corn (Zea mays). Data on the grain yield of 15 corn cultivars, evaluated in a randomized complete block design, with nine replicates (r = 9), were used. From the experiment with nine replicates, further experiments were conducted with combinations of 2, 3, ..., r-1 replicates. The analysis of variance was carried out for each experiment. Experimental precision statistics and central tendency and variability measures were calculated, dispersion diagrams were prepared, and models of these statistics were adjusted as a function of the number of replicates. The number of replicates was determined by the visual analysis of the graphs with the experimental precision statistics. Increasing the number of replicates improves the estimates of experimental precision but decreases gains. Therefore, the increase in the number of replicates is important to improve corn cultivar discrimination. Six replicates are recommended as the benchmark for experiments with corn cultivars. Fasoulas’ differentiation index, based on the percentage of significant contrasts, is an appropriate statistic for evaluating experimental precision.

Number of progenies and repetitions for reciprocal full-sib recurrent selection programs in maize

“…A similar result was found in this study. Cargnelutti Filho et al (2018) studied the influence of the number of repetitions on experimental precision. In this experiment, 15 maize cultivars and 9 repetitions were used, and grain yield was evaluated.…”

“…Additionally, it is important to use an appropriate number of repetitions to provide a good estimate of the experimental error and consequently increase the accuracy and power of the statistical tests (Silva Filho, 2013;Storck et al, 2016;Ribeiro et al, 2017). The adequate number of repetitions and progenies to estimate genetic parameters and dissimilarity or to compare genotypes has been studied by several authors for the most diverse crops and traits (Matei et al, 2017;Cargnelutti Filho et al, 2018;Toebe, 2020;Woyann et al, 2020).…”

“…However, the number of progenies and repetitions should not be so large that it makes the installation of the experiment unfeasible in terms of execution, time, and cost or so small as to undermine the representativeness of genetic variability and low experimental precision. Therefore, more studies aiming to identify the ideal number of cultivars and repetitions in maize are necessary (Cargnelutti Filho et al, 2018). The objectives of this study were to assess the potential of populations in the sixth cycle of RRS, and obtain information on the best combination between the number of progenies evaluated and the number of repetitions for use in RRS, aiming to optimize the prediction of genetic components, accuracy and, consequently, selection gain in an RRS of full-sibs.…”

Genetic variability and linear relationships between plant architecture and maize grain yield

“…This may have contributed to the lack of differences among cultivars in 18 traits in experiment 2 and in 17 traits in experiment 3. A higher number of replications is important to increase cultivar discrimination, and six replications is recommended for experiments with maize cultivars (CARGNELUTTI FILHO et al, 2018). Coefficient of variation (CV) for the 22 traits ranged between 3.71% and 16.94% in experiment 1; 4.84% and 22.44% in experiment 2; and 4.40% and 24.72% in experiment 3 ( Table 2).…”