Effective protocol to increase the percentage of grafting success of Pinus greggii Engelm. var. australis Donahue et Lopez

Introduction: Grafted plants of conifers are used in the establishment of clonal seed orchards, but with the methodology currently used, unsatisfactory results are reported. Objective: To compare grafting and growth of Pinus greggii var. australis scion from nursery and field stock plants grafted on four rootstocks. Materials and methods: Scions of P. greggii Engelm. var. australis Donahue et L??pez, collected from nursery stock plants (NSSP) and field trees (FSSP), were divided into terminal bud and basal segment, and grafted onto P. greggii var. australis, P. patula Schiede ex Schltdl. et Cham., P. teocote Schiede ex Schltdl. et Cham. and P. leiophylla Schiede ex Schltdl. et Cham. Percentage of grafting, height increment, diameter, scion-rootstock ratio and number of shoots (NS) were evaluated. Height and diameter increment data were subjected to an ANOVA and NS was analyzed with Poisson regression. Results and discussion: Grafting ranged from 93 to 100 %. The greatest increase in height was reported for P. teocote (14 cm) with scion from the terminal shoot of the nursery plant, while the combination P. greggii / P. leiophylla had the best scion-rootstock ratio with a value of 1. The highest NS was recorded with scion from the basal segment of NSSP. Getting two types of scions from one scion made the use of vegetative material more efficient. Conclusions: The use of nursery stock plants, 15-month-old rootstock, and two types of scions allowed having grafted plants in three months. The methodology developed was efficient, costeffective and fast.