The relationship between seedling survival rates and their genetic relatedness to neighboring conspecific adults

Seedling genotype is one of the major factors affecting seedling survival when the rate of damage by natural enemies depends on a host genotype. However, to our knowledge, no previous study has examined the mortality of seedlings adjacent to conspecific adults, considering intraspecific variation in seedling genotypes. On the basis of the assumption that natural enemies adapt to adult trees having a unique genotype, we tested the hypothesis that seedling survival decreases when they are more closely genetically related to neighboring adults, by measuring the mortality rate of seedlings of Fagus crenata growing in a cool-temperate forest in Japan. We estimated the genetic relatedness of seedlings (2 and 6 years old) to the neighboring adult F. crenata using microsatellite analysis and measured seedling survival. We determined that there was a non-significant negative correlation between seedling survival and genetic relatedness in the 2-year-old seedling cohort, and a non-significant but positive correlation in the 6-year-old seedlings. Our results call for further studies on the potential relationship between seedling survival and genetic relatedness to neighboring adults.