Resumo

ACEVEDO-RODRIGUEZ, Ramiro; VARGAS-HERNANDEZ, J. Jesús; LOPEZ-UPTON, Javier  e  VELAZQUEZ MENDOZA, Juan. Effect of geographic origin and nutrition on shoot phenology of mexican Douglas-Fir (Pseudotsuga sp.) Seedlings. Agrociencia [online]. 2006, vol.40, n.1, pp.125-137. ISSN 2521-9766.

To evaluate the implications on use of germplasm outside its natural habitat and on seedling production in the nursery, the influence of geographic origin and nutrition dose on shoot phenology traits was evaluated in Pseudotsuga sp. seedlings from seven populations obtained from different regions in México. Results showed significant variation (p≤0.01) among populations in dates of budburst and budset and in the duration of the growing season for the terminal shoot, with seven weeks of difference between extreme populations. Date of budburst was negatively correlated (r=−0.78) with the site elevation, suggesting an adaptative relationship with the threshold temperature to begin shoot growth. Although a simple geographic trend was not detected, northern populations had a different growing season with respect to populations from central México. In addition, seedlings from central México were less heterogeneous within populations in phenological traits, compared to northern seedlings. The high fertilization level accelerated budburst by ten days and retarded budset by nine days, increasing the growing season by almost three weeks and reducing the heterogeneity of the phenological events.

Palavras-chave : Pseudotsuga sp.; adaptation; shoot growth; vegetative; phenology; budset.

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