Vegetative and Adaptive Traits Predict Different Outcomes for Restoration Using Hybrids.

Area of Science:

• Ecology
• Genetics
• Conservation Biology

Background:

• Hybridization plays a role in speciation and extinction but can also yield resistant stock.
• Assessing the suitability of hybrid offspring for restoration is complex due to variable genetic proportions and phenotypic changes.
• Phenotypic averages may not reflect evolutionary drivers, potentially leading to unintended consequences in restoration.

Purpose of the Study:

• To develop and demonstrate a strategy for evaluating hybrids for restoration suitability.
• To visualize and compare hybrid phenotypes against progenitor species using discriminant analysis.
• To determine the ecological equivalency of hybrids for breeding and restoration efforts.

Main Methods:

• Used discriminant analysis to differentiate butternut, black walnut, and Japanese walnut based on vegetative and functional adaptive traits.
• Projected naturally occurring hybrids (J. × bixbyi) onto the trait space of progenitor species.
• Assessed morphological and ecological phenotypes of hybrids relative to butternut and Japanese walnut.

Main Results:

• Vegetative traits showed introgression of hybrids toward Japanese walnut.
• Functional adaptive traits revealed a hybrid swarm, indicating distinct ecological phenotypes.
• Some hybrids exhibited trait similarity to butternut seedlings, suggesting potential for restoration.

Conclusions:

• Hybrids possess distinct morphological and ecological phenotypes, indicating a lack of ecological equivalency with butternut for restoration.
• Discriminant analysis is a valuable tool for visualizing variation, assessing ecological equivalency, and guiding restoration breeding efforts.
• Consistent identification of suitable hybrid individuals is essential for future species restoration and breeding programs.