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Titolo:
THE IMPACT OF GENETIC-VARIATION IN RELATIVE GROWTH-RATES ON STEM VOLUME DIFFERENTIATION - A SIMULATION STUDY
Autore:
MAGNUSSEN S;
Indirizzi:
NAT RESOURCES CANADA,PETAWAWA NATL FORESTRY INST CHALK RIVER ON K0J 1J0 CANADA
Titolo Testata:
Silvae Genetica
fascicolo: 4, volume: 44, anno: 1995,
pagine: 194 - 205
SICI:
0037-5349(1995)44:4<194:TIOGIR>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
LOBLOLLY-PINE; DOUGLAS-FIR; PHENOTYPIC PLASTICITY; RED PINE; ENVIRONMENT INTERACTION; PLANT-POPULATIONS; STAND DEVELOPMENT; COMPETITION; MODEL; SELECTION;
Keywords:
HERITABILITY; COMPETITION; DENSITY; SELECTION; GENETIC GAIN; BIAS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
69
Recensione:
Indirizzi per estratti:
Citazione:
S. Magnussen, "THE IMPACT OF GENETIC-VARIATION IN RELATIVE GROWTH-RATES ON STEM VOLUME DIFFERENTIATION - A SIMULATION STUDY", Silvae Genetica, 44(4), 1995, pp. 194-205

Abstract

Time trends in quantitative genetic parameters of trees may be severely confounded by the effects of inter-tree competition, the temporal autocorrelation of growth, and the significance of size itself on future growth. When growth is a process influenced by both genetic and non-genetic factors the isolation of true genetic effects may be insurmountable. Realistic simulation studies can illustrate how growth dynamicsmay distort the genetic parameters and thus caution against naive interpretations of field results. Using a single-tree distance-independent stochastic growth model for stem volume, the influence of additive genetic control of relative growth rate on several growth and yield components (stem density, mean volume, total volume, and mean annual increment) was quantified. Growth results for 2 rotations (150 years), 3 levels of initial spacing, and 4 levels of genetic control are presented. The second rotation consisted of offspring from crop trees at the end of the first generation. Simulation results indicated an upper limit of 20% of the additive genetic contribution to the phenotypic variation in stem-volume. Classic heritability estimates of stem volume became grossly inflated by inter-tree competition. The magnitude of inflation was mirrored by the intensity of the competition process. Nevertheless, a narrow spacing appears more efficient for screening genotypes with a high growth potential than wider spacings. Genetic gains achieved by elimination of trees with slow growth rates (self-thinning) weremost pronounced during the juvenile phase of the second generation, and they could only be maintained at low levels of inter-tree competition. Volume and growth gains of about 5% per generation appears realistic when relative growth rates are under a fairly strong genetic control (heritability > 0.3).

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/12/20 alle ore 18:21:43