Genetic control of macro- and micro-environmental sensitivities in Populus

• Published in: Theoretical and applied genetics Vol. 94; no. 1; pp. 104 - 114
• Main Author: WU, R. L
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 1997; Berlin Springer Nature B.V
• Subjects: Biological and medical sciences; Classical genetics, quantitative genetics, hybrids; Correlation analysis; Divergence; Epistasis; Fundamental and applied biological sciences. Psychology; Genetic analysis; Genetic aspects; Genetic control; Genetic relationship; Genetic research; Genetics; Genetics of eukaryotes. Biological and molecular evolution; Heritability; Heterozygosis; Heterozygosity; Homeostasis; Inbreeding; Phenotypic plasticity; Physiological aspects; Poplar; Populus; Populus deltoides; Populus trichocarpa; Pteridophyta, spermatophyta; Vegetals; United States; Quantitative character; Phenotypic plasticity; Populus trichocarpa; Salicaceae; Populus deltoides; Dicotyledones; Angiospermae; Development; Environment; Instability; Spermatophyta; Hardwood forest tree; Heritability
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s001220050388

Understanding the genetic mechanisms for the phenotypic plasticity and developmental instability of a quantitative trait has important implications for breeding and evolution. Two clonally replicated plantations of two 3-generation inbred pedigrees derived from the highly divergent species Populus trichocarpa and P. deltoides were used to examine the genetic control of macro- and micro-environmental sensitivities and their genetic relationships with the trait mean across two contrasting environments. For all stem-growth traits studied, the trait mean had a higher broad-sense heritability (H(2)) level than macroenvironmental sensitivity, both with much higher H(2) values than microenvironmental sensitivity. Genetic correlation analyses indicated that the trait mean was more or less independent of macro- or micro-environmental sensitivity in stem height. Thus, for this trait, the genetic difference in response to the two environments might be mainly due to epistasis between some regulatory loci for plasticity and loci for trait mean. However, for basal area and volume index, pleiotropic loci might be more important for their genetic differences between the two environments. No evidence was found to support Lerner's (1954) homeostasis theory in which macro- or microenvironmental sensitivity is the inverse function of heterozygosity.