Abstract

HERNANDEZ-VERDUGO, Sergio et al. Phenotypic plasticity of populations of wild chile (Capsicum annuum var. glabriusculum) in responce to light availability. Bot. sci [online]. 2015, vol.93, n.2, pp.231-240. ISSN 2007-4476.  https://doi.org/10.17129/botsci.237.

Phenotypic plasticity allows plants to cope with heterogeneous environments. Wild Capsicum annuum is a valuable resource genetic that inhabits sites differing in light availability. We evaluated the genetic variation among populations, the phenotypic plasticity and its variation in response to three levels of light (high, 100%; medium, 50%; and low, 25% of sun light) of five wild Capsicum annuum populations from northtwestern Mexico. The traits measured were: plant height, stem diameter, leaf length, leaf width, fruit number, number of seeds per fruit, number of seeds per plant, and seed weight. Populations differed significantly in all traits measured. All characters showed significant treatment effect and all traits, except stem diameter showed significant population by treatment interaction effect, indicating high level of plasticity and variation in plasticity in the traits measured. This high number of significant interactions suggests that the populations of wild Capsicum annuum have the evolutionary potential to respond to variable environment in light availability. We tested the adaptive response to light by evaluating the relationship between phenotypic traits and seed number per plant as a measure of fitness. Under medium light treatment, selection favoured an increase leaf length and leaf width and a decreased stem diameter. Under low light, selection favoured a decreased stem diameter. These results indicate that selection and genetic drift could be responsible for the observed patterns of plasticity variation in the wild Capsicum annuum populations.

Keywords : light responses; phenotypic plasticity; population differentiation; reaction norm; wild Capsicum annuum.