Rapid Evolution of Seed Dormancy During Sunflower De-Domestication

Area of Science:

• Plant genetics
• Evolutionary biology
• Agricultural science

Background:

• Crop wild hybridization can drive the evolution of feral weeds.
• Wild sunflower (Helianthus annuus L.) is found in ruderal habitats, but hybridization may lead to weedy populations.

Purpose of the Study:

• Investigate the origin and genetic diversity of a weedy sunflower population (BRW).
• Assess rapid evolution of weedy traits like seed dormancy, herbicide resistance, and competitive ability using a resurrection approach.

Main Methods:

• Utilized one crop-specific mitochondrial marker (CMS-PET1) and 14 nuclear SSR markers.
• Employed a resurrection approach with samples from 2007 and 2017 to test for trait evolution.
• Confirmed feral origin using the CMS-PET1 cytotype.

Main Results:

• BRW population exhibited higher genetic diversity than cultivated lines and low differentiation from wild populations, indicating increased diversity via wild hybridization.
• Evidence for rapid evolution of increased seed dormancy was found.
• No significant evolution was detected for herbicide resistance or competitive ability.

Conclusions:

• Crop-wild hybridization is a significant factor in the evolution of feral weedy sunflower populations.
• Seed dormancy plays a crucial role in the early stages of adaptation for weedy species.
• Weedy crop-wild hybrids demonstrate rapid evolutionary potential in agricultural settings.