Distance between mates affects seedling characters in a population of Impatiens capensis (Balsaminaceae)

Tested for the presence of an optimal outcrossing distance in a population of Impatiens capensis, an annual herb that possesses a mixed mating system, by measuring fitness components for offspring of parents that were separated by distances of 2, 20 or 50 m. Heavier seed weights and later seed maturation enhanced probabilities of emergence and subsequent survival, but emergence and survival were unaffect by outcrossing distance. Seeds that were produced late in the season were heavier than early seeds, and late seeds germinated at later dates. Although late germination dates were associated with taller plants after 1 and 3 months of growth, late germination resulted in lighter dry weights at maturity. Distance between parents had a negative direct effect on seed weight but a positive effect on height after 1 month. Data imply an optimal outcrossing distance for height at 1 month, estimated as 29 m, but path analysis suggests that the apparent optimum is due to a negative correlation between the interparent distance and seed weight. -from Authors

Duke Scholars

Author Thomas Mitchell-Olds Biology