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Ecological Section

Geiger, John [1].

Breeding system investigation of the endangered vine Ipomoea microdactyla Griseb. (Convolvulaceae).

The loss of genetic diversity, specifically S-allele richness following population size decreases and entire population losses via habitat destruction, fragmentation and degradation, is especially detrimental for self-incompatible plant species now existing in isolated habitat remnants. Fragmented populations may experience the full range of reproductive effects: from increased reproduction to no change in reproductive output to complete reproductive failure and population extinction due to the loss of compatible mating types. Ipomoea microdactyla is an endangered vine with perfect flowers that occurs in the highly fragmented pine rockland habitat of Miami-Dade County, Florida, USA. Field observations of very low fruit production at most sites led to an hypothesis of self-incompatibility. To determine the breeding system attribute of self-compatibility versus self-incompatibility, a program of controlled pollinations was performed on plants propagated from cuttings from four populations. Also, several morphological and physical features were investigated to differentiate between the two self-incompatibility systems, gametophytic and sporophytic. Preliminary results show the species to be mostly self-incompatible and incapable of agamospermy, i.e. fertilization without pollination. In terms of fruit set, there was no significant difference between within site and among site cross-pollination treatments. For a nearly complete diallel cross of the 21 genotypes, most of the pollinations were at least one-way compatible. Other evidence at this time points to a sporophytic system of self-incompatibility, as has been shown for several species within Convolvulaceae.

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1 - Florida International University, Department of Biological Sciences, 11200 Sw 8Th Street, Oe167, Miami, Florida, 33199, USA

breeding system
habitat fragmentation.

Presentation Type: Oral Paper
Session: 37-1
Location: Salon A - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 2:00 PM
Abstract ID:123

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