3-MODE ANALYSES OF MAIZE USING MORPHOLOGICAL AND AGRONOMIC ATTRIBUTES MEASURED IN MULTILOCATIONAL TRIALS

This study provides examples of the application of three-mode methods to agronomic and morphological data from multiattribute and multilocational trials of accessions from two Mexican maize (Zea mays L.) races, Conico and Tuxpeno. Initially, Conico accessions from the state of Mexico were classified into five subgroups, whereas Tuxpeno accessions were classified into three subgroups based on the ecogeographical region of origin. A three-mode classification method reassigned accessions to form more homogeneous subgroups. The new Conico groups were called C1, C2, C3, C4, and C5 and the new Tuxpeno groups were named T1, T2, and T3. Intra-racial genetic diversity was investigated by three-mode principal component analysis. Most Conico Group C3 accessions had low grain yield, early maturity, short plants, and short ears. Group C2 accessions had the tallest plants, the shortest kernels, and the narrowest ears; whereas, Group C4 accessions had the longest kernels and the widest ears. Accessions in Groups C1 and C5 were the highest yielders and had the longest ears. A core subset would include accessions from all five subgroups with an approximate average response for all attributes, plus some accessions with extreme responses. Tuxpeno Group T2 accessions were earlier and had shorter plants than the accessions from Group T1. Group T3 accessions had higher grain yield and longer kernel length. A core subset of Tuxpeno accessions could be formed as suggested for Conico. If a Tuxpeno core subset with high grain yield and shorter plant type is desired, more accessions from Groups T2 and T3 should be included.