Scion and rootstock compatibility in Pinus patula Schiede ex Schltdl. & Cham. in response to genotypic variation

Introduction: Clonal orchards increase genetic gain, usually established by grafting. In pines, scion rootstock genetic compatibility could improve grafted plant production.Objectives: To evaluate scion-rootstock compatibility of Pinus patula Schiede ex Schltdl. & Cham. in response to genotypic variation.Materials and methods: Scions of four outstanding genotypes (G105, G106, G114 and G115) were grafted onto rootstocks of the same half-sib families (F105, F106, F114 and F115) in all combinations in a randomized complete block design. The following were evaluated: grafting, survival, needle development and growth in length and diameter of the graft. Results and discussion: The analysis of variance indicated that grafting ranged from 70 to 82.5 %; the effect was significant only for the scion genotype factor (P < 0.0001), being higher with G115. The genotype*family interaction had significant effect (P < 0.0001) on graft survival; the best combinations were G115 + F114 (85 %), G114 + F105 (80 %), G115 + F105 (75 %) and G115 + F106 (75 %). G105 (26 cm) and G115 (2 mm) had the highest values (P < 0.05) for growth in length and diameter, respectively. All the grafts developed needles after five months.Conclusions: Grafting with genotype G115 and family F105, in combination with any family or genotype, were the most successful. Scions and rootstocks of the same genotype or family were not favorable for graft compatibility in P. patula.