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Tallahassee, FL, United States

Merkle S.,University of Georgia | Cunningham M.,ArborGen Inc.
Journal of Forestry

Varietal forestry appears poised to make significant contributions to the production of woody crops for timber, pulp and paper, and biomass energy in the southeastern United States. The projected productivity gains with southern pine somatic seedling technology make a strong case for adopting parallel technologies with southern hardwoods. Systems for producing somatic seedlings of multiple southern hardwoods have been developed and in some aspects are already more amenable to scale-up and manipulation than conifer systems. The feasibility of scaling up production of elite, varietal hardwoods using somatic embryogenesis has already been established. By combining this propagation system with hybrid breeding, thousands of somatic seedlings of elite hybrid sweetgum and hybrid yellow-poplar have been generated, some of which have shown impressive biomass productivity in field tests. Varietal, blight-resistant chestnuts now being developed may have even greater potential to be deployed for biomass plantations and other applications in the southern Appalachians. © 2011 by the Society of American Foresters. Source

Patrick Cumbie W.,ArborGen Inc. | Isik F.,North Carolina State University | McKeand S.E.,North Carolina State University
Forest Science

Progeny from 48 elite parents of loblolly pine (Pinus taeda L.) were bred in a disconnected diallel mating design and were planted at four sites across the lower coastal plain of the southeastern United States. Height, dbh, volume, fusiform rust incidence (caused by the fungus Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme), stem forking, stem sweep, branch angle, branch diameter, branch frequency, and a sawtimber potential score were measured after six growing seasons. There were significant differences among families for all traits measured. Individual-tree narrow-sense heritability estimates ranged from 0.06 to 0.22 and half-sib family-mean heritability estimates ranged from 0.73 to 0.98. Height and volume were the traits most highly correlated with the sawtimber potential score of individual trees. From multiple regression, 79% of the variation in sawtimber potential breeding values can be attributed to variation in volume, rust incidence, stem sweep, and forking breeding values. The potential dollar value of loblolly pine was increased as much as 162% over local checks when both volume and sawtimber potential were used to select the 10 best parents from the population. Implementation of a selection index on currently measured traits is a promising opportunity to make gains in the proportion of sawtimber produced from improved germplasm of loblolly pine in the southeastern United States. © 2012 by the Society of American Foresters. Source

Maier C.A.,U.S. Department of Agriculture | Johnsen K.H.,U.S. Department of Agriculture | Dougherty P.,ArborGen Inc. | McInnis D.,U.S. Department of Agriculture | And 2 more authors.
Forest Science

Soil incorporation of postharvest forest floor or logging residues during site preparation increased mineral soil carbon (C) and nitrogen (N) concentration and had a differential effect on early stand growth in a clonal loblolly pine (Pinus taeda L.) plantation. Incorporating 25 Mg ha -1 of forest floor (FF) (C/N ratio ≈ 112:1) or 25 (1LR) or 50 (2LR) Mg ha -1 masticated logging residues (C/N ratio ≈ 856:1) increased soil C concentration by 24-49% in the top 60 cm of soil compared with that for a nontreated control or a raked (R) treatment where the forest floor (-25 Mg ha -1) was removed. Although the long-term treatment effects on soil C are unknown, increased macro-organic matter C (150-2,000 μm) in the recalcitrant heavy fraction coupled with an estimated 20- to 35-year turnover rate for the incorporated residues suggests that soil C will be elevated in the FF, 1LR, and 2LR treatments through the current rotation. There was a treatment × age interaction on stand volume growth (P = 0.03) caused by a differential response to FF and LR treatments. Relative to the control, the FF treatment increased stem volume growth and stand homogeneity, resulting in 18% more stand volume at age 6. In contrast, the LR treatments initially suppressed volume growth; however, at age 6 there were no significant differences in stem volume among control and LR treatments. Six-year stand volume was 116.6, 112.6, 135.1, 116.0, and 112.3 (SE 3.6) m 3 ha -1 in the control, R, FF, 1LR, and 2LR treatments, respectively. Whereas the efficacy of organic matter management will be site-dependent, our results suggest that soil incorporation of forest residues during site preparation can have positive benefits for productivity and building soil C on sites with relatively high inherent soil C stocks. © 2012 by the Society of American Foresters. Source

Four eastern cottonwood clones, including standard operational clone ST66 and three advanced clonal selections were produced and included in a test utilizing five different plant propagation methods. Despite relatively large first-year growth differences among clones, all clones demonstrated similar responses to the treatments and clone × cutting treatment interactions were generally non-significant. The effects of changing cutting lengths are consistent with previous studies which indicated the potential for increased plant survival and growth with increased cutting lengths. Differences in stored carbohydrate reserves alone do not appear to completely control first-year growth and development of cuttings. First-year growth of 51 cm long cuttings planted 30.5 cm deep was greater than the same cuttings planted 48 cm deep. Stem form of plants derived from whip-tip propagation did not differ from plants derived from standard, unrooted cuttings. This propagation method offers the potential of far greater production capacity from a cutting orchard and rapid bulk-up of new or limited clones. Stand uniformity assessments suggest that surviving trees of each individual cutting treatment exhibit similar levels of growth variation. Optimization of plantation establishment techniques has the potential to increase growth of young Populus plantations. © 2014 Springer Science+Business Media Dordrecht (outside the USA). Source

ArborGen Inc. | Date: 2015-02-20

The invention provides polynucleotide sequences isolated from plants encoding transcription factors. Polypeptides encoded by the polynucleotides are also provided. Products and methods of use are disclosed.

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