scholarly journals HORTICULTURAL PROPAGATION TECHNIQUES APPLIED TO SOFTWOOD CUTTINGS OF JUVENILE LOBLOLLY PINE (PINUS TAEDA L.), A SOUTHERN FOREST SPECIES

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 607e-607
Author(s):  
Farrell C. Wise ◽  
Laura L. Greenwood ◽  
D. Bradley Rowe

Clonal propagation of recalcitrant conifers like loblolly pine depends on producing juvenile cuttings on hedges sheared several times annually. Although dormant cuttings root well, it will be economically important to also root softwood shoots produced between shearings. Several variables were therefore evaluated in a factorial experiment to enhance rooting and handling of summer cuttings. Rooting percentages were equivalent for 3 media after a 5-week hardening period (56% overall), but open flats of 1 perlite:1 vermiculite induced larger root systems at the end of rooting and hardening phases. Extending the rooting period from 10 to 14 weeks increased rooting from about 45% to 58% by the end of hardening. Primary root length per cutting increased 12-63% during hardening, depending on medium. After transplanting, overwintering survival was 98%. Foam rooting wedges produced smallest root systems, and resulting plants were consistently shortest through the following growing season. Weekly applications of soluble fertilizer during the last 6 weeks of rooting did not improve rooting or subsequent growth

1980 ◽  
Vol 4 (2) ◽  
pp. 70-73 ◽  
Author(s):  
Frank W. Woods

Abstract Loblolly pine (Pinus taeda L.) planted in two locations with roots in straight, slanted, L-shaped, P-shaped, and balled configurations were excavated and measured seven years after planting. At each location, there were no differences (P = .05) between treatments in survival, height growth, or d.b.h. However, at one site and for pooled data from both sites, trees with balled roots had smaller root collars than trees with L-shaped roots. There was no firm evidence that trees planted with bent, balled, or slanted root systems were less productive than those planted with a straight tap root.


1982 ◽  
Vol 6 (2) ◽  
pp. 104-107
Author(s):  
R. S. Webb ◽  
S. A. Alexander

Abstract The root systems of 70 loblolly pines (Pinus taeda L.) from three subsoiled seed orchards were excavated to determine the association of subsoiling with the incidence of resin-soaked lateral roots. The number of lateral roots and the proportion of resin-soaked and healthy root tissue were recorded. Chips from the resin-soaked margin of lateral roots were incubated for 10 days at 24°C on two general media and two media selective for Heterobasidion annosum (Fr.) Bref. Verticicladiella procera Kend. was isolated from 30 percent of the declining/subsoiled trees at one seed orchard. Monilia spp. were also isolated. Of the lateral roots severed by subsoiling, 60 percent were resin-soaked from 10 to 45 cm in length.


Genetics ◽  
1999 ◽  
Vol 151 (1) ◽  
pp. 321-330 ◽  
Author(s):  
Mitchell M Sewell ◽  
Bradley K Sherman ◽  
David B Neale

Abstract A consensus map for loblolly pine (Pinus taeda L.) was constructed from the integration of linkage data from two unrelated three-generation outbred pedigrees. The progeny segregation data from restriction fragment length polymorphism, random amplified polymorphic DNA, and isozyme genetic markers from each pedigree were recoded to reflect the two independent populations of parental meioses, and genetic maps were constructed to represent each parent. The rate of meiotic recombination was significantly greater for males than females, as was the average estimate of genome length for males {1983.7 cM [Kosambi mapping function (K)]} and females [1339.5 cM(K)]. The integration of individual maps allows for the synthesis of genetic information from independent sources onto a single consensus map and facilitates the consolidation of linkage groups to represent the chromosomes (n = 12) of loblolly pine. The resulting consensus map consists of 357 unique molecular markers and covers ∼1300 cM(K).


2021 ◽  
Vol 491 ◽  
pp. 119176
Author(s):  
Michael A. Blazier ◽  
Thomas Hennessey ◽  
Laurence Schimleck ◽  
Scott Abbey ◽  
Ryan Holbrook ◽  
...  

1997 ◽  
Vol 21 (3) ◽  
pp. 116-122 ◽  
Author(s):  
Thomas A. Waldrop

Abstract Four variations of the fell-and-burn technique, a system developed to produce mixed pine-hardwood stands in the Southern Appalachian Mountains, were compared in the Piedmont region. All variations of this technique successfully improved the commercial value of low-quality hardwood stands by introducing a pine component. After six growing seasons, loblolly pine (Pinus taeda L.) occupied the dominant crown position and oaks the codominant position in fell-and-burn treated stands on poor to medium quality sites. The precise timing of felling residual stems, as prescribed by the fell-and-burn technique, may be flexible because winter and spring felling produced similar results. Although summer site preparation burns reduced hardwood height growth by reducing the length of the first growing season, they did not improve pine survival or growth. Pines were as tall as hardwoods within four growing seasons in burned plots and within six growing seasons in unburned plots. Additional research is needed to determine the level or intensity of site preparation needed to establish pine-hardwood mixtures over a range of site conditions. South. J. Appl. For. 21(3):116-122.


1997 ◽  
Vol 21 (2) ◽  
pp. 84-89 ◽  
Author(s):  
Steven E. McKeand ◽  
Robert P. Crook ◽  
H. Lee Allen

Abstract The lack of rank change in growth characteristics when open-pollinated families of loblolly pine (Pinus taeda L.) are planted on different sites in the Southeast has greatly simplified breeding for superior genotypes. Although family rank does not usually change, genotype by environment interactions (GxE) may be very important in operational deployment of families in regeneration programs. Using data from GxE trials and two site preparation-fertilization-herbicide trials, we estimated the growth that different families should achieve following application of these silvicultural practices. Better performing families tend to be most responsive to site changes (i.e. genetically unstable). Growth responses to silvicultural treatment will be overestimated if only the most responsive families are used in silvicultural research trials. Similarly, genetic gains will be overestimated if gain trials are planted on only the best sites or receive intensive culture. South. J. Appl. For. 21(2):84-89.


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