Common Names: apple of Sodom, bull nettle, Carolina horsenettle, devil's tomato, horsenettle, sand briar
Researchers found that the weed Solanum carolinense can adjust the strength of its self-incompatibility (SI) system. Inbred plants produced fewer ramets than outbred plants, and suffered more herbivore damage. In year one, inbred plants showed 0.63% inbreeding depression (δ), which rose to 0.79% in year two. Outbred plants produced 2.5 times more ramets than inbred ones in year two. Overall, the weed has a total δ of 0.85, meaning it's not fully self-compatible, and its plasticity in the SI system is part of a mixed-mating system that allows self-fertilization when cross-pollination is lacking. This shows the importance of genetic diversity for successful reproduction and survival.
This study investigated the effect of inbreeding on the success of horsenettle, a successful weed with a self-incompatibility system. Controlled self- and cross-pollinations of 16 genets were performed to obtain progeny with different levels of inbreeding, which were then grown in greenhouse and field conditions. The researchers found that inbreeding depression varied by family, but overall, inbred progeny showed reduced growth and reproductive success compared to outcrossed progeny. The study highlights the importance of genetic diversity in the success of plant species and suggests that the plasticity of self-incompatibility in horsenettle may allow it to adapt to changing environmental conditions.