Impact of external and internal factors on successful grafting of Pinus pseudostrobus var. oaxacana (Mirov) Harrison

Introduction: Grafting allows full multiplication of phenotypic and genotypic characteristics of genetically improved trees. Objective: To determine the influence of bud origin, rootstock fertilization, grafting period and grafting techniques on the success of grafting, growth, and survival of intraspecific grafts in Pinus pseudostrobus var. oaxacana (Mirov) Harrison. Materials and methods: The effect of four factors was evaluated ([a] two bud sources, [b] three rootstock fertilization doses, [c] three grafting seasons and [d] two grafting techniques) on the success of grafting, shoot growth (Sg) and survival. An analysis of variance was carried out to determine the effect of factors a, b, c, and d on successful grafting and Sg, and a Log-Rank test was carried out for survival analysis. Results and discussion: Significant differences (P ≤ 0.05) were obtained for factors a,c and d. Grafting during winter (December 2018 and February 2019) using the side-veneer grafts technique and buds coming from Santa Catarina Ixtepeji showed the highest values of successful grafting (≥25.5 %), Sg (≥14.5 cm) and survival (≥20.5 %). Final survival decreased from 100 to 27 % 90 days after grafting. Conclusions: Grafting period, bud origin, and grafting technique, individually or interacting with, are determinant factors for the success of intraspecific grafting on P. pseudostrobus var. oaxacana.