Pollination Investigations for Production of the Hybrid between Slash and Caribbean Pines

Abstract

SYNOPSIS The detail of the pollination process in trees of slash pine (Pinus elliottii Engelm. var. elliottii L.&D.) has been studied following applications of mixtures of Honduras Caribbean pine (Pinus caribaea Mor. var. hondurensis B. & G.) and slash pine pollen in controlled pollinations. The studies have provided guidelines for pollen application in the monoclonal orchards, established in Queensland to produce seed of the hybrid between slash and Caribbean pines. These new orchards contain a single clone of slash pine and the pollen of Caribbean pine is applied artificially during the flowering period. Variation occurred between slash pine clones in seed potential and in the number of pollen grains usually present inside the pollen chambers. Both features may affect a clone's capacity to produce hybrid seed. The stage of cone development determined the entry of the pollen of both species. Caribbean pine pollen had no difficulty entering the pollen chambers in competition with slash pollen provided it ...