Resumo

MORALES-NIETO, Carlos R. et al. Morphological characterization of native populations of sideoat grama [Bouteloua curtipendula (Michx.) Torr.] in Mexico. Agrociencia [online]. 2008, vol.42, n.7, pp.767-775. ISSN 2521-9766.

The morphological descriptors involve the management of attributes to carry out breeding of forage species. The objectives of the present study were to explore the morphological diversity of native populations of sideoat grama [Bouteloua curtipendula (Michx.) Torr.] and to evaluate its principal morphological characteristics. To this effect, 177 ecotypes were qualified and analyzed at the moment of flowering by means of 14 quantitative morpological descriptors to know and define the population structure. The data were analyzed using principal components (PCA) and hierarchic analysis of conglomerates (HAC). There was a high morphological variability among ecotypes. The first three components (PC) explained 63.3% of the total variation observed. For PC1, the most important variables were length of inflorescence, stem diameter at the base and at the mean height of the tillers; for PC2, tiller density, forage height and plant height, and in PC3, branch length, length of the inflorescence of the rachis and number of branches. These variables contributed significantly with the highest values to explain the total variation. PC1 grouped variables related to the tiller; with PC2 it was observed that the forage potential is related to tiller density and forage height; with PC3, that the length and number of branches are related to seed yield. When the HAC was applied, five groups were obtained: I with 19 ecotypes, II with 29, IV with 22 and V with 62. Ecotypes with high forage potential were detected according to their morphological variability; therefore, there is genetic wealth in sideoat grama.

Palavras-chave : Bouteloua curtipendula; principal components; morphological descriptors; morphological variability.

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