REPRODUCTIVE CHARACTERISTICS VARIATION IN Pinus patula TREES AT A SEXUAL SEED ORCHARD

Abstract

Seed orchards are important to produce germplasm for forest plantation establishment. The objective of this study was to evaluate the variation of reproductive characteristics of cones and seeds in a Pinus patula Schiede ex Schltdl. et Cham at a sexual orchard. The reproductive characteristics variation was considered to be influenced by the genetic constitution of the trees and by environmental differences. The study was conducted in an orchard at Cuaunepantla, Acaxochitlán, Hidalgo, México. The experimental design was completely random and cones were the minimum experimental unit. The number of sampled cones varied with the production of three years in 19 sampled trees. The analyzed variables were dry cone weight, potential seeds number, percentage of aborted ovules, inbreeding index, seed weight, reproductive efficiency and full, empty and plagued seeds. All the variables showed differences between trees (p£0.01) and between production years (p£0.05). The number of damaged seeds (3 %) was higher in 2012. Dry cone weight (32 g), seed potential (117 seeds per cone), full seeds percentage (58 %), seed weight (9.5 mg) and reproductive efficiency (22 mg g-1 ) were higher in 2013. The percentage of aborted ovules and average inbreeding index (0.25) were higher in 2014. The variation levels were high in the reproductive characteristics of P. patula. The low inbreeding rate indicated low selffertilization.