Quantitatively determined self-incompatibility : 2. Outcrossing inBorago officinaux

Area of Science:

• Botany
• Plant reproductive biology
• Agricultural science

Background:

• Borage (Borago officinalis L.) is purported to have a complex self-incompatibility system.
• Self-incompatibility systems can lead to inefficient pollination, impacting seed production.

Purpose of the Study:

• To investigate the pollination and self-incompatibility mechanisms in borage.
• To evaluate the effectiveness of different pollination methods in borage seed set.

Main Methods:

• Assessing seed set under various pollination conditions: bee-pollination, natural pollination (with and without bees), artificial cross-pollination (related and unrelated plants), and artificial self-pollination.
• Conducting diallel crosses to analyze parental effects on seed set.
• Estimating the level of outcrossing under natural pollination.

Main Results:

• Seed set varied significantly across pollination treatments, with bee-pollination yielding the highest and artificial self-pollination the lowest.
• Diallel crosses revealed significant parental effects but no consistent patterns indicative of a simple self-incompatibility system.
• Natural pollination showed a highly variable outcrossing rate, consistently exceeding 50%.

Conclusions:

• Borage exhibits a high level of ineffective pollination, consistent with complex reproductive strategies.
• The study's findings challenge the notion of a straightforward self-incompatibility system in borage.
• Borage demonstrates a significant level of outcrossing, indicating a reproductive system more complex than simple self-incompatibility.