Genetic relationships in accessions of mexican maize races (Zea mays L.)

Abstract

Objective: Characterize representative accessions of mexican maize races with ISSR molecular markers, which help to infer genetic relationships linked to their origin, morphology, ecogeographic aspects, distribution and uses.

Design/methodology/approach: 54 representative accessions of mexican maize races characterized with ten ISSR molecular markers were used. Genetic distances were calculated with the Dice coefficient and the dendrogram was generated using the hierarchical clustering method of Ward's minimum variance. To visualize the accessions in two dimensions, a Principal Coordinate Analysis was carried out with the standardized minimum variance method.

Results: In 76 loci detected, the cluster analysis with a semi-partial R2 of 0.04 build five groups that shared phylogenetic, ecogeographic, morphoagronomic, distribution and special use characteristics. The main coordinate analysis showed 21.2% of the total variation for the first two coordinates. First main coordinate explained 12.43% of the total variation and separated the accessions by geographical location and special uses, that is, those used for breeding programs and for special culinary uses; second main coordinate explained 8.77% of the total variation and separated the samples by altitudinal ranges and biological cycle.

Limitations on study/implications: Only one representative accession was used for each maize race, considering the genetic variability of this crop, more accessions of the same race should be included.

Findings/conclusions: Genetic relationships between race accessions are due to altitudinal and geographical patterns; although some groupings shared phylogenetic, morpho-agronomic, distribution and use aspects.

Keywords: Genetic variability, plant genetic resources, molecular characterization, integral classification.