Relationships among the Mexican races of maize

The present study was designed to advance the classification of the Mexican races of maize as part of the process of revising the Razas de Maíz en México by Wellhausen et al. The interrelationships among the races are examined by numerical taxonomy of morphological characters and the comparison of classifications with previous studies. Forty-nine Mexican races, represented by 148 collections, were grown in several locations and seasons in México from 1982 to 1984; 47 characters were measured directly. For the analysis using numerical taxonomy, characters with the ratio \(r = \hat \sigma ^2 _r /(\hat \sigma ^2 _{re} + \hat \sigma ^2 _e )] \geqslant 3.0\) were chosen. Classifications of Mexican races indicate general agreement with the relationships found in previous studies which were based on conventional taxonomic methods and numerical taxonomy. In addition, poorly described races and new types may now be assigned to well defined groups.