title: Remnant Pachira quinata pasture trees have greater opportunities to self and suffer reduced reproductive success due to inbreeding depression.
abstract: Habitat fragmentation is extensive throughout the world, converting natural ecosystems into fragments of varying size, density and connectivity. The potential value of remnant trees in agricultural landscapes as seed sources and in connecting fragments has formed a fertile area of debate. This study contrasted the mating patterns of bat-pollinated Pachira quinata trees in a continuous forest to those in pasture through microsatellite-based paternity analysis of progeny. The breeding system was determined by analysis of pollen tube growth and seed production from controlled pollinations. Fitness of selfed and outcrossed seed was compared by germination and seedling growth. There was more inbreeding within pasture trees (outcrossing=0.828±0.015) compared with forest trees (0.926±0.005). Pasture trees had fewer sires contributing to mating events, but pollen dispersal distances were greater than those in the forest. Paternity analysis showed variation in outcrossing rates among pasture trees with high proportions of external and self pollen sources detected. A leaky self-incompatibility system was found, with self pollen having reduced germination on stigmas and slower growth rate through the style. Controlled pollinations also showed a varied ability to self among trees, which was reflected in the selfing rates among pasture trees shown by the paternity analysis (0-80% selfing). Self pollination resulted in lower seed set, germination and seedling growth compared with outcrossing. While remnant trees in agricultural landscapes are involved in broader mating patterns, they show increased but varied levels of inbreeding, which result in reduced fitness.
authors: 1] Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, UK [2] Hawkesbury Institute for the Environment, University of Western Sydney, Bourke Street, Richmond, Australia.
authors: P D
authors: PD
authors: Rymer
authors: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, UK.
authors: M
authors: M
authors: Sandiford
authors: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, UK.
authors: S A
authors: SA
authors: Harris
authors: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, UK.
authors: M R
authors: MR
authors: Billingham
authors: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, UK.
authors: D H
authors: DH
authors: Boshier
mesh_terms: D003364:Costa Rica; D018744:DNA, Plant / Q000235:genetics; D065928:Forests; D056084:Genetic Fitness; D014644:Genetic Variation; D005828:Genetics, Population; D005838:Genotype; D007178:Inbreeding; D019660:Malvaceae / Q000235:genetics*; D018895:Microsatellite Repeats; D011058:Pollen / Q000235:genetics; D012098:Reproduction / Q000235:genetics; D012639:Seeds / Q000235:genetics; D057945:Self-Fertilization; D060436:Self-Incompatibility in Flowering Plants; D017422:Sequence Analysis, DNA; D014197:Trees / Q000235:genetics*
chemical_list: D018744:DNA, Plant
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