Environmental and genetic determinants of plant size in Viola sororia.

Abstract

Survivorship and fecundity in the forest herb Viola sororia, are size-dependent. Analysis of quantitative variation showed: 1) significant differences between light treatments for characters related to plant shape and relative growth rate; 2) significant among-genet variation for plant size, plant shape and relative growth rate but none for physiological characters; and 3) a size threshold for cleistogamous seed production and rhizome production. Heritability estimates for the characters associated with plant size and shape ranged from 0.09--0.39, indicating significant genetic determination for these traits. Also, among-genet differences in relative growth rate were substantial. Size variation found in natural populations is thus not solely a function of environmental heterogeneity but is significantly influenced by the genotypes composing the populations.-from Authors