Resumo

MUNOZ FLORES, H. Jesús et al. Harvest seasons and treatments for the rooting of grafts of Tilia mexicana Schlecht. (Tiliaceae). Rev. mex. de cienc. forestales [online]. 2011, vol.2, n.3, pp.13-24. ISSN 2007-1132.

The cirimo tree ( Tilia mexicana Schlecht.) is an endangered species that is widely used in Michoacán, México. It is necessary to develop effective propagation methods to ensure its survival. The general objective was to propagate cirimo, and the particular objectives was to assess the effect of different collection dates as well as the length and diameter of stem cuttings on the best rooting, using IBA. Root proliferation was observed in the first collection, resulting in 39.3 % of cuttings rooting. Because the rooting percentage was 0% in the subsequent three collections, the statistical analysis was performed for September for the different analyzed variables. The optimal proliferation of roots (51.1 %) was observed in explants of 20 cm length and 1.5 cm diameter, which formed 3.06 roots/cutting of 0.9 cm length with an average diameter of 0.47 cm. There were significant differences (P>F=0.012) among treatments in root diameter. The longest cuttings with high diameter produced shorter roots with the highest diameter, while the smaller cuttings produced the longest roots with smaller diameter. All the four collections resulted in callus formation, but the percentage varied according to the date and the size of the explants, with the cuttings of December collection showing the highest percentage (30.1 %). Best rooting response occurred in cuttings collected during late summer, since it is also the budding season, which might explain the seasonal effect that promotes rooting capacity.

Palavras-chave : Rooting; stake; Michoacán; vegetative propagation; Tilia mexicana; nurseries.