Morphological characterization of endemic Agave cupreata species of Mexico

Abstract

The agave papalote (<i>Agave cupreata</i> Trelease) which is endemic to the Guerrero state, Mexico, is propagated exclusively by seed, but it is overutilized and knowledge of its diversity is needed for its protection. Therefore, the study aimed to determine the morphological variation in wild and cultivated populations of <i>Agave cupreata</i> in five areas of Guerrero. Ninety one characters were evaluated <i>in situ</i>, and only 51 qualitative and quantitative morphological characters of the plant, leaf spine, flower, fruit, seed and flower stalk were selected. The work was carried out in five different altitudinal zones, according to the level of production of mezcal. In each area we selected 20 plants. We used multivariate and cluster analysis. The principal component analysis indicated that the first six principal components (PC) accounted for 60.1% of the total variation. The CP1 was related to plant height, and CP2 to growth habit and leaf shape. We identified five groups. Morphological characterization <i>in situ</i> allowed detecting morphological variation in wild and cultivated agave. This variation was detected in growth habit, rosette height, stem length, leaf shape, margin shape, number of ribs, terminal spine width, length and thickness of the marginal bone. We also propose 37 varietal descriptors that differentiate ecotypes of <i>A. cupreata</i>. This will contribute to perform the legal protection of this type of agave endemic to Mexico, and thereby promote its conservation and sustainable use.