Intraspecific seed competition and genetic diversity within the capsule fruits of <i>Aristolochia contorta</i>

Abstract Genetic diversity and competitive dynamics are crucial in shaping plant communities. However, these dynamics have not been examined thoroughly in the context of seed position within a fruit. This study integrated genetic analysis and seed competition experiments to understand genetic diversity and competitive dynamics within Aristolochia contorta . By combining molecular markers and seed competition trials, we aimed to deduce the roles of genetic factors and seed position in influencing seedling success, facilitating a comprehensive assessment of both genetic and environmental contributions to growth patterns in this species. Centrally positioned seeds showed superior growth and germination rates due to their larger size and weight, providing a competitive edge over peripheral seeds, highlighting the influence of seed position on nutrient allocation and competition during germination. Regarding fruit orientation during sowing, vertically upward‐sown fruits showed the highest number of shoots per fruit, suggesting that the physical orientation of the fruit may influence early seedling growth. This result emphasizes the importance of environmental factors (such as light exposure and soil contact) in determining the success of early‐stage seedlings. Genetic diversity was low within and among fruits, with genetic differentiation also being low among groups. Most genetic variation was observed within individuals rather than between groups, indicating a relatively homogeneous genetic structure within the population. The low genetic diversity may be attributed to the species' reproductive strategies, particularly the low efficiency of pollinators, which restricts gene flow and variation. In summary, these results suggest that non‐genetic factors, such as environmental conditions and seed position, play a significant role in seedling success and competitive interactions. Our findings provide valuable insights into evolutionary biology and conservation strategies of A. contorta . The observed low genetic diversity highlights potential challenges for the species in adapting to environmental changes. Our findings remain robust despite the small sampling size and the use of whole seeds for DNA extraction. They emphasize the importance of considering environmental factors and seed position in conservation efforts. Read the free Plain Language Summary for this article on the Journal blog.