SEXUAL REPRODUCTION IN A GREENHOUSE AND REDUCED AUTUMN FROST HARDINESS OF PICEA-ABIES PROGENIES

In 1989, identical crosses (2-3 females within males) were performed w ith Picea abies (L.) Karst. in a greenhouse seed orchard at Biri nurse ry and in an outdoor seed orchard at Huse, 32 km north of Biri. Pollin ation began 17 days earlier in the greenhouse than outdoors at Huse. T he potted grafts in the greenhouse were moved outdoors when the seed c ones were no longer receptive. Twelve full-sib family pairs (Biri and Huse) from these crosses were grown in a phytotron and tested for heig ht and autumn frost hardiness during their first growing season. No si gnificant difference was found between the indoor (Biri) and outdoor ( Huse) progenies for height growth. However, the progenies from the gre enhouse seed orchard were significantly more susceptible to frost than their full-sibs from the outdoor seed orchard. There was no significa nt interaction between males and the flowering environment, but a sign ificant female x flowering environment interaction was present as a re sult of greater differences in frost hardiness between progenies from females in the greenhouse seed orchard than in the outdoor seed orchar d. Although seeds from the outdoor seed orchard generally had a greate r biomass than seeds from the greenhouse seed orchard, the difference in seed weight did not explain the difference in frost hardiness. We h ypothesize that temperature and photoperiod during pollination and fer tilization affect the frost hardiness of the progenies.