Cross-virility in 2 exotic forest species: proof of inbreeding despair contained in this populations and you will hereditary divergence certainly one of communities †
Mcdougal thank you so much S. Gunatilleke and you can Letter. Gunatilleke at Department out of Botany, College or university regarding Peradeniya to possess guidance and you can logistic service; the fresh Tree Institution of Sri Lanka to own permission to run which functions in Sinharaja Community Heritage Website; the latest Botany Agency, School of Peradeniya for use of its institution; S. Harischandran, H. Gamage, and Yards. Gunadasa getting advice about hand-pollinations; and you may S. Harischandran and you may A. Anura having tending greenhouse seedlings. P. Ashton, K. Bawa, N. Gunatilleke, J. Hamrick, L. Kaufman, and you can J. Mitton provided helpful talks; P. Ashton, S. Dayanandan, and you can C. Schneider commented into prior to drafts; and you can B. Wieninger helped to the numbers. It functions try supported in part from the money from the brand new Maintenance, Eating, & Health Basis, Inc.
Abstract
Understanding the spatial activities off get across-virility into the pure bush communities output key understanding of biparental inbreeding despair, isolation of the range, and you may, fundamentally, speciation. About three adults each of a couple of exotic tree varieties (Syzygium rubicundum and you may Shorea cordifolia) had been for every entered with four conspecific pollen donors between care about to help you woods occurring in the independent tree reserves (several and you can thirty five kilometres length to have S. rubicundum and you will Sh. cordifolia, respectively). Cross-fertility is actually projected because fresh fruit set, seed germination, and you may seedling survivorship and you can peak in the step 1 yr. Means of most get across-fertility tips increased continuously that have outcrossing point, peaking at 1–dos kilometer getting S. rubicundum and you will 1–ten kilometer getting Sh. cordifolia, then declining within anywhere between-tree crosses. But not, seed germination and you may seedling peak getting Sh. cordifolia ideal crossbreed vigor between-tree crosses. The latest indicate physical fitness price of nearest-next-door neighbor mating in accordance with crossing with increased faraway residents is actually forty-five% getting S. rubicundum and 0% to have Sh. cordifolia. The indicate exercise cost of ranging from-tree crosses was 52% and 70% on the two species. Crossing outcomes towards fitness diminished within degrees off fresh fruit put and you will step 1-yr-dated seedlings. Performance mean a powerful possibility inbreeding depression within forest forest communities and partial reproductive isolation certainly forests during the Sri Lanka’s damp zone.
Estimating cross-fertility at several spatial balances inside a herb species’ range allows insight into the significance of hereditary incompatibility and you will inbreeding and you may outbreeding anxiety below sheer criteria. Within shorter spatial scales, the newest restricted seed dispersal trait of many plants would be to result in relatedness one of near-natives inside the sheer populations. In which nearby flowers is associated, mating anywhere between residents (we.elizabeth., biparental inbreeding; Uyenoyama, 1986) could lead to shorter reproductive physical fitness because of inbreeding depression or hereditary incompatibility anywhere between friends. When you are activities regarding great-measure hereditary relatedness was indeed revealed for a number of herbaceous kinds (elizabeth.grams., Epperson and you will Clegg, 1986; Waser, 1987; Schoen and you can Latta, 1989), to own woody species, such as for example angiosperms, data on the in this-populace genetic structure is actually minimal. Certain studies have revealed spatial clustering away from adult genotypes (otherwise alleles) within the animal-pollinated forest trees (Acer saccharum-Perry and Knowles, 1991; Swartzia simplex-Hamrick, Murawski, and you may Nason, 1993; Quercus rubra-Sork, Huang, and Wiener, 1993; Quercus laevis-Berg and you will Hamrick, 1995; Cordia alliodora-Boshier, Pursue, and you can Bawa, 1995), and others have failed to support the fresh assumption regarding hereditary relatedness certainly surrounding grownups (Psychotria nervosa-Dewey and you may Heywood, 1988; Alseis blackiana and you may Platypodium elegans-Hamrick, Murawski, and Nason, 1993). Regardless of patterns regarding relatedness, mating is sometimes limited to regional neighborhoods inside herbaceous varieties (Levin and you may Kerster, 1974; Endler, 1979; Waser and Rates, 1983) plus in woody kinds, particularly when flowering grownups was clustered (Linhart, 1973; Stacy mais aussi al., 1996). The opportunity of biparental inbreeding depression into the absolute rencontres par âge que des avis populations has been demonstrated for many herbaceous and coniferous forest kinds (Coles and you will Fowler, 1976; Park and you will Fowler, 1982; Levin, 1984; Schemske and you may Pautler, 1984; McCall, Mitchell-Olds, and you may Waller, 1991; Heywood, 1993; Waser and you can Speed, 1994; Trame, Coddington, and you can Paige, 1995; Byers, 1998). Almost no is known, yet not, regarding biparental inbreeding despair in pure communities out of woody angiosperms.