RELATIONSHIPS AMONG AMERICAN AND SPANISH POPULATIONS OF MAIZE

Two experiments were carried out with two objectives. First, to establ ish the phenetic relationships among the maize (Zea mays L.) landraces from Galicia (Northwestern Spain) maintained at the Mision Biologica de Galicia. Second, to assess the resemblance between a collection of Spanish populations (including the landraces from Galicia) and a set o f US Corn Belt varieties. For the first objective 73 varieties from Ga licia, along with 9 hybrid checks, were grown in 9 x 9 simple lattices at two locations for two years. For the second objective 131 populati ons from the US Corn Belt and Spain, along with 9 hybrid checks, were grown for three years in unreplicated experiments. Cluster analyses we re carried out with the first principal components that accounted for a significant amount of the total variation. Four groups were found am ong the landraces from Galicia. The populations from Spain and America were classified as belonging to nine main groups. The replicated expe riment was more accurate than the unreplicated one. However, it is con cluded that an unreplicated test grown in several environments is accu rate enough to detect the main groups, although some inaccuracies shou ld be expected.