Abstract
Provenance-progeny test plantations of loblolly pine (Pinus taeda L.) were assessed for survival, height, mean annual increment for volume (MAIV), and fusiform rust infection (caused by Cronartium quercuum [Berk] Miyabe ex Shirai f. sp. fusiforme) at 5, 10 and 15 yr. Each of the 7 sites contained from 6 to 15 open-pollinated families from each of 4 provenances: Atlantic Coastal Plain (ACP), Central Florida (CF), Marion County Florida (MCF), and Gulf Coastal Plain (GCP). The main objectives for establishing these trials were to: (1) characterize the genetic architecture among and within these provenances; and (2) determine the relative genetic worth of these provenances for possible inclusion in advanced-generation breeding programs in the Coastal Plain in the southeastern United States. Provenance and family within provenance effects were strong and highly significant for height and MAIV, but only family effects were significant for rust infection. The Florida provenances were the best growers at all ages and at all sites. The poor growth of the Gulf Coastal Plain provenance compared to the Atlantic Coastal Plain provenance could not be explained by climatic or edaphic differences between the regions of origin. We speculate that gene flow from slower growing sources on the western side of the Mississippi River may be at least partly responsible for the poor growth of the GCP loblolly. Because of the relatively stable performance of the provenances and the families within provenances at each site and across ages, selection of superior families for growth and rust resistance between ages 5 and 10 yr should result in substantial genetic gain in the Coastal Plain. For. Sci. 48(4):732–742.