Identifying Subsets of Maize Accessions by Three-Mode Principal Component Analysis

Gencbank accessions are a potential source of genetic variability for maize (Zea mays L.) breeding programs. Identification of useful individual entries is commonly based on the expression of one or more attributes in different sites or environments. This study was motivated by the need to identify a subset of Caribbean accessions for introgression in to elite germplasm of the western Corn Belt. Thus the objective was to identify potentially useful Caribbean accessions, based on (i) simultaneous consideration of six agronomic attributes deemed economically important for the western Corn Belt, and (ii) response patterns observed across four sharply contrasting environments. Both (i) and (ii) were addressed by means of three-mode principal component analysis (PCA) of data on six agronomic and morphological attributes for 184 Caribbean maize accessions evaluated at four environments. Three-way data were analyzed by three-mode PCA and based on (i) and (ii), two joint plots were generated. From the PCA and joint plots, two subsets of accessions were identified. First, a subset of 14 accessions having body yield, intermediate plant height, and average days to anthesis was identified. Secondly, a subset of 10 accessions having average performance over all environments was identified. Two accessions were common to both subsets. Jointly, the two approaches produced a combined subset of 22 accessions, representing 12% of the total evaluated, and including representatives of 11 maize races. Three-mode PCA integrated information on accessions, attributes, and environments, and provided a means of simultaneously visualizing these three types of information. Three-mode PCA can complement standard methodologies used by plant breeders for identification of potentially useful accessions in introgression programs. Contribution of the Agric. Res. Div., Univ. of Nebraska-Lincoln. Published as Journal Series Number 11513.