Location: Soil Management ResearchTitle: The integrated phenotype and plasticity of Cuphea PSR23: A semi-domesticated oilseed crop
Submitted to: Communications in Biometry and Crop Science (CBCS)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/9/2015
Publication Date: 1/1/2016
Citation: Jaradat, A.A. 2016. The integrated phenotype and plasticity of Cuphea PSR23: A semi-domesticated oilseed crop. Communications in Biometry and Crop Science. 11(1):10-30.
Interpretive Summary: Understanding the interactions and inter-dependencies of plant traits is important to advancing our knowledge of a crop development. Also, it is important for its adaptation to new environments and to alternative management practices. Cuphea is a semi-domesticated potential oilseed crop that produces high-quality oil appropriate for several industrial and food applications. Several cycles of planting and harvesting may have resulted in indirect selection for certain plant architecture and yield-related traits under agricultural management. This process may have resulted in a reduced level of trait combinations necessary for plant adaptation under varying environmental conditions. Under managed agricultural systems, Cuphea plants became larger because they invested more in traits involved in competition for light and other renewable and non-renewable resources. Reduction in trait association and integration may affect the possibility of improving Cuphea to withstand future climate conditions. The compiled information on this potential oilseed crop is of value to agronomists and oilseed breeders in defining which plant traits are necessary for its full domestication and to improve its seed and oil yields.
Technical Abstract: Cuphea PSR23, a semi-domesticated potential oilseed crop, is a selection from an interspecific cross between the wild species Cuphea lanceolata and C. viscosissima. Understanding the extent to which its phenotype is integrated, by studying complex trait interactions and interdependencies, is critical for its full domestication, as well as for advancing our knowledge of its developmental plasticity, and adaptation to new environments and alternative management practices. Phenotypic plasticity is necessary for Cuphea’s adaptation to changing environments and may become inversely related to the former, especially under abiotic stress. Phenotypic integration was quantified using several multivariate statistical procedures on log- or z-transformed raw data, or on latent variables derived from phenotypic or nutrient variables within structural, metabolic and reproductive plant modules. Several estimates of the level of phenotypic integration were used to generate phenotypic integration indices (PIIs) as the deviation of functionally linked phenotypic, eco-physiological, and nutrient traits from the means of respective traits in its wild parents. These traits were assessed in Cuphea PSR23 in response to directional selection under cultivation for high seed weight, seed yield, and oil content. Under managed agro-ecosystems and compared to its wild parents, Cuphea PSR23 displayed complex phenotypic traits that are naturally highly dimensional; it invested more in phenotypic and eco-physiological traits that are related to larger biomass and to stronger inter-plant competition under high population densities; and displayed wide variation in the scale and significance of bivariate and multivariate trait (dis)associations. However, Cuphea PSR23 may have become less phenotypically integrated due to directional population selection for a few agronomic traits under cultivation. Reduction in phenotypic integration if continued under cultivation, may render PSR23, as a semi-domesticated oilseed crop, more vulnerable to abiotic stresses, and may delay its full domestication unless systemic germplasm enhancement and breeding programs are launched for genetic and agronomic improvement.