Taxon and family differences in survival, cold hardiness, early growth, and rust incidence of loblolly pine, slash pine and some pine hybrids

• Published in: Silvae genetica Vol. 48; no. 6; pp. 303 - 313
• Main Authors: LOPEZ-UPTON, J, WHITE, T. L, HUBER, D. A
• Format: Journal Article
• Language: English
• Published: Frankfurt am Main Sauerländer 1999
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Generalities. Genetics. Plant material; Genetic resources, diversity; Genetics and breeding of economic plants; Pinus caribaea; Pinus elliottii; Pinus taeda; Plant material; Hybrid variety; Plant pathogen; Silviculture; Growth; Insecta; Pinus taeda; Basidiomycetes; Early stage; Genetic determinism; Population genetics; Fungi; Pinus elliottii; Disease resistance; Softwood forest tree; Gymnospermae; Silvicultural systems; Thallophyta; Cultural practice; Cold resistance; Tortricidae; Sensitivity resistance; Arthropoda; Lepidoptera; Genetic improvement; Coniferales; Spermatophyta; Invertebrata
• ISSN: 0037-5349; 2509-8934

Seven taxa, including open-pollinated families of improved P. taeda (PTA), improved (PEE) and unimproved P. elliottii (PEU) and four hybrid's families, PEE x PTA, PEE x P. caribaea var. bahamensis (PEE x PCB), PEE x P. caribaea var. hondurensis (PEE x PCH), and the backcross PEE to PEE x PCH, were tested in eight field tests in the lower Coastal Plain of the southeastern (northern Florida and southern Georgia) USA. Each field test included 16 families per taxon and two silvicultural treatments, intensive and less intensive. Results at three years of age indicated that PTA was the best taxon, and PEE was next. PEE x (PEE x PCH) and PEE x PCB were less affected by cold damage and taller than PEE x PCH, and had height growth similar to the PEE families. All slash x Caribbean hybrids were more susceptible to fusiform rust than PEE. The PEE x PTA hybrid was intermediate for rust incidence and height growth to the PEE and PTA parental species, but mean values were closer to PEE. Taxon ranking for height growth was not affected by cultural treatments, but differences increased in the intensive treatment. Outstanding healthy trees were detected in all hybrid taxa. Larger hybrid heritabilities (h super(2) sub(h)) and more within hybrid family variability for height compared to within families of parental species were detected and this may be exploited by selection within hybrid families to find outstanding recombinants. If these early results are confirmed in later years, the technique of reciprocal recurrent selection does not hold much promise since it is based on operational deployment of the F1 hybrids and none of the hybrids tested here outperformed the current pure taxa being deployed (PEE and PTA). The excellent individual trees within hybrid taxa might be useful for breeding purposes in hybrid programs that combine genes from the hybrids back with the parental PEE and PTA species in various combinations to form synthetic taxa.