Autonomous self-fertilization in Linum sulcatum, a native annual with a previously unknown mating system

Area of Science:

• Plant reproductive biology
• Evolutionary botany
• Ecology

Background:

• Mating systems critically influence plant genetic structure and evolution.
• The breeding system of Linum sulcatum (Linaceae) is largely unknown, despite assumptions of self-compatibility.

Purpose of the Study:

• To experimentally determine the self-compatibility and mating system of Linum sulcatum.
• To investigate the modes of selfing (autonomous vs. facilitated) and assess outcrossing success within and between populations.

Main Methods:

• Controlled pollination experiments on cultivated Linum sulcatum.
• Floral manipulations to assess self-fertilization and outcrossing rates.
• Pollen tube growth experiments to analyze fertilization dynamics.

Main Results:

• Self-fertilization in Linum sulcatum was highly successful and occurred autonomously.
• Outcrossing success, both within and between populations, was extremely limited, suggesting strong cross-incompatibility.
• Self-pollination led to more pollen tube formation and faster growth (<2 hours) compared to cross-pollination.

Conclusions:

• Linum sulcatum possesses a highly self-compatible breeding system with autonomous selfing.
• Extreme cross-incompatibility may limit gene flow and adaptation in fragmented populations.
• Understanding the mating system is crucial for the conservation of Linum sulcatum in its threatened habitats.