Correlations among fertility components can maintain mixed mating in plants

Area of Science:

• Evolutionary biology
• Plant reproductive strategies
• Population genetics

Background:

• Classical evolutionary models predict stable states of either complete self-fertilization or complete outcrossing.
• Empirical data show a significant proportion of seed-plant species exhibit intermediate selfing rates (0.2–0.8).
• Previous models may be limited by not accounting for complex interactions among reproductive fitness components.

Purpose of the Study:

• To develop and analyze a model predicting optimal selfing rates in plants.
• To investigate the role of functional relationships among reproductive fitness components in shaping mating system evolution.
• To assess the influence of inbreeding depression and selection on total seed number on selfing rates.

Main Methods:

• Developed a theoretical model incorporating functional relationships between self-fertilized ovules, outcrossed ovules, and pollen export.
• Analyzed the model under various relationships among fitness components.
• Included the effects of evolving inbreeding depression and selection for total seed number.

Main Results:

• Intermediate selfing rates are predicted to be optimal across a wide range of functional relationships among fitness components.
• Inbreeding depression was found to be a poor predictor of selfing-rate evolution.
• Functional relationships provide a more general framework for understanding mating system evolution than focusing on individual traits.

Conclusions:

• The evolution of intermediate selfing rates is explained by considering the interplay of different reproductive fitness pathways.
• Plant mating system evolution is better understood through functional relationships rather than solely through inbreeding depression.
• This modeling approach offers a simplified yet comprehensive perspective on the evolution of plant reproductive strategies.