Outbreeding Challenged:
Autogamy and Apomixis, New Contenders in
Any accession that exhibited
autogamy or which did not have L.
lepidus is capable of
autogamy (in the presence of wind agitation) and a pollen addition experiment in 1991 provided no evidence for pollen limitation (J.
The final three traits, corolla length, flower width, and stigma-anther separation, were measured because they are likely to be important in the attraction of pollinators and in the probability of
autogamy. Stigma-anther separation is correlated with
autogamy rates across several taxa of Mimulus (Ritland and Ritland 1989), and an overall reduction in flower size is a common feature of selfing Mimulus species that are believed to be recently derived from outcrossing taxa (e.g., Macnair and Cumbes 1989; Ritland and Ritland 1989).
Autogamy was recorded only among species of Tillandsia subgenus Diaphoranthema, characterized by neotenic species with a tendency toward polyploidy (Till, 1992).
[2] through [5] allow the estimation of [N.sub.e(v)] for species with a given rate s and can be extended to the extreme cases of panmixia (s = 0) or complete
autogamy (s = 1).
Although flowers set fruit following experimental pollination with pollen from the same individual (and are thus considered self-compatible; Munoz and Devesa 1987),
autogamy (i.e., within-flower pollination) rarely occurs in nature because of marked protandry.
The second plant was retained in case the first plant died, and to provide a second estimate of the
autogamy rate within each family.
10B) may have changed from insect pollinated to pure
autogamy, but
autogamy is not uncommon in this genus, so this failsafe system may even have facilitated establishment of colonizers.
Two of the five [F.sub.1] hybrids, HG276-7 (hybrid of G31276 [is greater than](AG-S4) and HG31721 (hybrid of G31317) [is less than] AG-S4), were chosen to produce [F.sub.2] seed without manipulation of flowers, i.e., by
autogamy. Backcross (BC) generations were obtained by crossing HG276-7 and HG317-21 to their respective parents to produc BC-R ([F.sub.1] hybrids )[is less than] Moroccan parent, where R designates a rhizomatous parent) and BC-NR ([F.sub.1] hybrids ) [is less than] AG-S4, where NR designates a nonrhizomatous parent) generations.
drummondii, Salmon Beauty, to selection for increased and decreased
autogamy. We specifically address the following questions: (1) To what extent can the self-compatible and self-incompatible breeding systems of the two wild species be altered by two cycles of artificial selection?
Early maturity, small flowers and
autogamy: A developmental connection?