Morphological characterization of Opuntia spp. accessions for potential use as a forage crop in dry areas of Bolivia

Abstract

Morphological characterization is an important procedure to identify desirable traits that could be used to detect accessions from Opuntia spp. for usage as forage in arid and semiarid zones of Bolivia. In this study, 80 accessions of Opuntia spp. were collected from Cochabamba and La Paz. The characterization was based on morphological traits using 2-year-old plants that were already well established in the experimental field at the Forage Research Center, Cochabamba. Plant descriptors, with five variables (qualitative and quantitative), and cladode descriptors, with 24 variables (qualitative and quantitative), were considered. Multivariate principal component analysis and cluster analysis showed two groups, both with two sub-established groups; the first group represents accessions with upright, medium and arborescent habitus and the second group represents accessions with spreading and shrubby habitus. The results of the cluster analysis indicate that the two groups obtained are independent of the origin of collection, suggesting that the high diversity of Opuntia spp. is not determined by the zone of collection. The accessions differed with respect to many morphological traits: thicker cladodes; absence of spines, form of plant, serous accession, longest cladode, and large number of cladodes. Other accessions formed a more homogeneous group. The following growth habits were observed in the majority of studied accessions: spreading, shrubby, arbustive, medium and less, upright and arborescent. Four accessions with desirable traits to be used as fodder were identified. The traits considered for use as a forage crop are plants with no or few spines, without disease, long and wide cladode and large number of cladodes.