Maize landraces characterization using Generalized Procrustes Analysis and Multiple Factor Analysis

The establishment of relationships among taxa is an essential step in the process of cataloging and evaluation of material conserved in a germplasm bank. There are several evaluation methods according to the types of the characters in the study. When the registration of the characters should be repeated in diverse environments and times, it is necessary to separate the genetic variability of the taxa from the variability due to the environment, and from the possible genotype*environment interaction variability. Consequently, pure phylogenetic relationships may be established. In this work, the feasibility of application of two strategies of statistical analysis to give solution to this problem is studied comparatively. The first one is a traditional Principal Component Analysis applied on the average characters. The second one is a set of more complex methods where each datum is originated by three ways: individuals, variables and environmental conditions, as the Multiple Factorial Analysis and the Generalized Procrustes Analysis. While the resulting configurations were all equivalent, three-way methods allow the interpretation of genotype*environment.