Provenance hybridization in a diallel mating scheme of maritime pine (Pinus pinaster). I. Means and variance components

Growth and survival from age 1 to 13 years, stem straightness, and resistance to Dioryctria splendidella Herr. Schaff. were assessed in 154 families belonging to interprovenance hybrids of maritime pine (Pinus pinaster Ait.). The hybrids were part of a full 10 × 10 diallel mating scheme. The 10 parental provenances belonging to the three major geographic groups of maritime pine (Atlantic, Mediterranean, and North African) were also included in the experiment as controls. The variance among families within an interprovenance hybrid combination represented only a minor part of the total variance, except for height and survival from age 1 to 3 and resistance to Dioryctria. General combining abilities were more important than specific combining abilities for all traits except for survival during the juvenile stages. General reciprocal effects were only significant for height at age 1 and stem straightness at age 8. A few hybrids between Atlantic and Mediterranean or North African provenances combined the good growth of the former provenance with the excellent stem straightness of the latter ones, suggesting new alternatives for tree improvement.