ENVIRONMENT-DEPENDENCE OF QUANTITATIVE GENETIC PARAMETERS IN IMPATIENS PALLIDA

Area of Science:

• Evolutionary Biology
• Ecology
• Genetics

Background:

• Population response to selection relies on additive genetic variance.
• Environmental changes can alter genetic variance expression, impacting adaptation.
• Impatiens pallida populations exhibit ecotypic differentiation between floodplain and hillside habitats.

Purpose of the Study:

• To investigate the environment-dependence of genetic variance in Impatiens pallida.
• To assess how different environments affect heritability and adaptive potential.
• To understand the implications for populations invading stressful habitats.

Main Methods:

• Reciprocal transplant experiment using progeny of a standard mating design.
• Comparison of two distinct ecotypes (floodplain vs. hillside) of Impatiens pallida.
• Measurement of 13 life-history and morphological traits and estimation of heritability.

Main Results:

• Heritability estimates were generally low (0-28%) across traits and sites.
• Additive genetic variance was larger for life-history traits than morphological traits.
• Heritability decreased in the stressful hillside environment, indicating reduced genetic variance expression.

Conclusions:

• Stressful environments reduce the expression of genetic variance, limiting adaptive potential.
• Populations in stressful environments may experience less adaptive differentiation.
• Reduced adaptive capacity increases the risk of local extinction for invading populations.