VEGETATIVE PROPAGATION OF Pinus patula SCHIEDE ex SCHLTDL. et CHAM. IN DIFFERENT SUBSTRATES

Abstract

Pinus patula Schiede ex Schldl. et Cham. is an endemic species of Mexico used in commercial forest plantations in South America and South Africa. Massive propagation of improved materials of this species, through rooted cuttings, allows the increase of productivity and homogenized products. Five substrates based on fresh sawdust and pine bark at different proportions (1: 9, 3: 7, 5: 5, 7: 3 and 9:1 v:v) were compared to assess rooting of this forest species. A randomized complete block experimental design with four replications was used; the experimental unit was made up of 25 rooted cuttings. The main physical and chemical characteristics of the substrates such as total porosity, aeration porosity, moisture retention, bulk density, pH, electrical conductivity and cation exchange capacity were analyzed at the beginning and the end of the experiment. The evaluated variables were survival, rooting, callus presence, number and length of primary roots and presence of secondary roots 20 weeks after the experiment was established. The substrate with the highest proportion of sawdust (9:1) had the highest percentage of rooting (77 %), compared to the control (1:9), where 42 % were rooted. High correlation (0.97, 0.97, 0.90) of rooting was observed with sawdust percentage, bulk density and pH, respectively. The mixture of sawdust and pine bark (9:1) presented appropriate physical and chemical characteristics for the formulation of substrates useful for propagating Pinus patula by rooted cuttings.