Relative efficiency of the alpha lattice and randomized complete block designs in maize trials

Abstract

The objective of this work was to compare the relative efficiency of the alpha lattice design (ALD) with that of the randomized complete block design (RCBD) in maize (Zea mays) genotype trials. For this, data from 627 trials were used. In each trial, variance components were estimated for grain yield under both designs. The statistical parameters coefficient of variation (CV), heritability, range, least significant difference (LSD), standard error, and coefficient of determination (R²) were calculated for various sources of variation and the residual. The LSD/range ratio was used as a measure of experimental precision. The analysis of the trials in the ALD not only improved the R² of the design (0.62 in the ALD versus 0.42 in the RCBD) and of the genotypes, but also reduced experimental error (0.38 in the ALD versus 0.58 in the RCBD) in more trials than the RCBD. Overall efficiency (RCBD/ALD) varied by statistic, but generally favored the ALD analysis. Specifically, heritability increased from 0.72 in the RCBD to 0.77 in the ALD, while CV decreased from 12.7% in the RCBD to 11.0% in the ALD. The ALD shows a higher relative efficiency than the RCBD in the analysis of maize genotype trials.