EFFECTS OF THE PARENTAL ENVIRONMENT ON FULL-SIB FAMILIES OF PINUS-SYLVESTRIS

Identical pair crosses, including reciprocals, in Pinus sylvestris L. (Scots pine) were made on ramets of the same clones in three clonal archives (seed orchards) in Sweden: Savar (64-degrees-N), Roskar (59.5-degrees-N), and Degeberga (56-degrees-N). The offspring were used to test the hypothesis that the parental environment could affect the performance of the progeny (aftereffects). Growth and freezing tests were performed in the controlled conditions of the Stockholm Phytotron. Parental environment affected seed weight: the heaviest seeds came from Roskar and the lightest seeds, from Degeberga. Height development was affected in the two growth periods tested: seeds from Savar produced the shortest plants and seeds from Roskar, the tallest plants. There was an effect on the autumn frost hardiness in the first growth period that disappeared after the second growth period. The most hardy progenies came from Savar. The aftereffects of the parental environment were less than the maternal effects on seed weight and also less than the effects of full-sib families on growth and autumn frost hardiness. Small but mostly significant reciprocal effects were found for height and height increment during the second growth period. There was a significant reciprocal effect for seed weight. Seed weight differences could explain only a small part of the effects on growth and none of the effects on hardiness.