Growth variation in nursery among provenances of Pinus pseudostrobus Lindl.

Pinus pseudostrobus is a species with timber harvesting, distributed over a wide altitudinal gradient of 1,600-3,250 m, suggesting a genetic variance, which can be exploited by selecting trees that provide seeds in order to produce plants with high relative growth rates. Therefore, survival and early growth of Pinus pseudostrobus were evaluated under nursery conditions, based on the variation in offsprings of 38 outstanding trees (provenances) in natural stands from Sierra Norte of Oaxaca, Mexico. Seeds were sowing in February 2013 at a nursery located in Ixtlan de Juarez, near the collection site, to 2030 masl and a temperate climate. Survival from 54-166 days after planting (dap) was evaluated, five readings of plant height, basal stem diameter, four readings of number of brachyblasts were recorded, and the relative growth rate for plant height was estimated. Using analysis of variance and mean tests, significant differences among provenances were determined in all variables. In the evaluation, the plants in the nursery showed an exponential growth, an average of 0,8 to 1,5 mm in height/day of 54-166 dap and an average of 1-2 brachyblasts on primary and secondary branches per day in a range of 82-166 dap. From total provenances, four showed high growing rate.