Data from: Complex cross incompatibility in morning glories is consistent with a role for mating system in plant speciation

Reproductive isolation between selfing and outcrossing species can arise
through diverse mechanisms, some of which are directly associated with
differences in mating system. We dissected cross incompatibility between
the highly selfing morning glory Ipomoea lacunosa and its mixed-mating
sister species I. cordatotriloba. We found that cross incompatibility is
complex, with contributions acting both before and after fertilization. We
then investigated whether the transition in mating system may have
facilitated the evolution of these reproductive barrier components through
mismatched floral morphology, differences in reproductive context, or
both. We found evidence that morphological mismatch likely contributes to
reproductive isolation in at least one cross direction and that other
pollen-pistil interactions are present. We also identified hybrid seed
inviability consistent with the predictions of the weak-inbreeder,
strong-outbreeder hypotheses, suggesting endosperm misregulation plays an
important role in cross incompatibility. In contrast, we did not find
evidence consistent with the pre-zygotic weak-inbreeder, strong-outbreeder
hypothesis. Our study highlights the complexity of reproductive isolation
between outcrossing and selfing species and the extent to which
evolutionary consequences of mating system transitions can facilitate
speciation.