Modeling genetic effects on growth of diverse provenances and families of loblolly pine across optimum and deficient nutrient regimes

Abstract

Optimal deployment of improved loblolly pine (Pinus taeda L.) planting stock in the southeastern United States requires knowing how diverse seed sources and families perform over time across the wide range of sites used for plantations. This study tests if the relative growth performance of provenances and families is the same at the individual-tree and stand levels for family block plantings and determines what type of adjustment may be required to account for genetic differences when modeling growth and yield. Ten open-pollinated families from two very different provenances, Atlantic Coastal Plain and "Lost Pines" Texas, were grown in single-family block plots to test for growth differences between provenances and among families under severely deficient and optimal nutrition regimes on a nutrient-deficient, dry site. The three-parameter Chapman-Richards function was fit to plot means over time by provenance, family, and nutrition treatments. Models with provenance-or family-specific parameters of the Chapman-Richards function were tested for significant improvement over global parameters. At age 14 years, family, provenance, and nutrition treatments all significantly affected individual-tree growth traits of height, diameter, and volume. Significant nutrition by provenance interactions were found for stand-level traits of basal area per hectare and volume per hectare. Family differences were also significant for these traits. Provenance-or family-specific asymptotic parameters accounted for differences in growth over time. Several traits required the use of local asymptotic and rate parameters in the fertilized treatment only. For modeling growth, a multiplier would be sufficient to account for genetic effects on the majority of traits.Résumé : Le déploiement optimal des plants améliorés de pin à encens (Pinus taeda L.) dans le sud-est des États-Unis demande des connaissances sur le rendement des plantations dans le temps en fonction de l'origine des graines et des familles pour toute la gamme de stations utilisées. Cette étude vérifie la similitude de croissance relative entre les provenances et les familles aux échelles de l'arbre et du peuplement pour des familles plantées en bloc. On veut aussi vérifier quel type d'ajustement peut être nécessaire pour tenir compte des différences génétiques lors de la modélisation de la croissance et du rendement. Dix familles à pollinisation libre de deux provenances très différentes, la plaine côtière de l'Atlantique et « Lost Pines » au Texas, ont été plantées dans des parcelles composées de blocs à famille unique pour vérifier les différences de croissance entre les provenances et les familles sous des régimes nutritifs optimal et fortement carencé sur une station sèche et pauvre en nutriments. La fonction de Chapman-Richards à trois paramètres a été ajustée aux moyennes des parcelles en fonction du temps, de la provenance, de la famille et du traitement nutritionnel. Nous avons testé si les modèles avec des paramètres de Chapman-Richards spécifiques à la provenance ou ...

Development of improved and comprehensive growth and yield models for genetically improved stands

“…where Y is the yield of a characteristic of interest (e.g., height, diameter, volume, or basal area; see, e.g., Smith et al 2014) at age A; a is the asymptotic parameter, which represents the asymptotic maximum size of the organism; b is the rate parameter, which represents the intrinsic growth rate; c is the shape parameter, which is related to the power exponent of assimilation; and ε is a normally distributed zero-expectation random error due to observation of the total growth at age A (Richards 1959). Models of unimproved stands simulated using Eq.…”

“…In addition to genetic factors, the parameters of stand growth and yield models are influenced by environmental factors that may exhibit different spatial characteristics, such as soil attributes (including soil fertility, texture, moisture, and depth), climate, topography, and wind exposure (Smith et al 2014). Phenotypic responses of genotypes in different environments are distinct, resulting in differences in stand growth patterns (Fu et al 1999;Silva et al 2001;Baltunis et al 2010;Rohner et al 2018).…”

The Polish Provenances of European Larch Overperform the Expected Growth Dynamics Indicated by the Sigmoid Model

“…For instance, Colbert et al [9] compared four different functions and indicated that the Chapman-Richards function was prominent. To date, two studies employed a similar approach to compare the differences in growth among provenances [10,11]. Both studies were carried out in the early stages of stand development: at 11 and 14 years old.…”