Cross-virility in 2 exotic tree varieties: evidence of inbreeding depression inside communities and you may hereditary divergence certainly populations †
The author many thanks S. Gunatilleke and N. Gunatilleke in the Department from Botany, College or university regarding Peradeniya getting recommendations and you may logistic service; the fresh Tree Institution from Sri Lanka getting consent in order to conduct this work inside the Sinharaja Globe Traditions Website; the new Botany Company, University off Peradeniya for use of the business; S. Harischandran, H. Gamage, and Yards. Gunadasa to own help with hand-pollinations; and you may S. Harischandran and Good. Anura having tending greenhouse seedlings. P. Ashton, K. Bawa, Letter. Gunatilleke, J. Hamrick, L. Kaufman, and you may J. Mitton considering helpful discussions; P. Ashton, S. Dayanandan, and C. Schneider stated into prior to drafts; and you will B. Wieninger helped to your numbers. That it functions is offered to some extent by the money from the Conservation, Eating, & Fitness Basis, Inc.
Abstract
Knowing the spatial patterns out of get across-virility from inside the absolute bush communities production secret insight into biparental inbreeding depression, isolation because of the length, and, in the course of time, speciation. Around three adults each of one or two tropical tree kinds (Syzygium rubicundum and you may Shorea cordifolia) was in fact for each and every entered which have five conspecific pollen donors anywhere between worry about so you’re able to trees taking place in independent tree reserves (several and 35 km point for S. rubicundum and you may Sh. cordifolia, respectively). Cross-virility was estimated since fresh fruit lay, seeds germination, and you may seedling survivorship and you may height on 1 yr. Technique of very cross-fertility actions increased steadily with outcrossing range, peaking at step one–2 kilometer for S. rubicundum and you may 1–ten km to possess Sh. cordifolia, and declining on between-tree crosses. not, seed products germination and seedling level to have Sh. cordifolia ideal crossbreed vigor between-tree crosses. The fresh imply physical fitness cost of nearby-neighbor mating in line with crossing with more faraway natives was 45% getting S. rubicundum and 0% to possess Sh. cordifolia. New imply fitness price of between-tree crosses is 52% and you will 70% toward two varieties. Crossing effects into the physical fitness reduced between the amount away from fresh fruit set and step 1-yr-old seedlings. Efficiency mean an effective possibility inbreeding depression within this forest tree communities and you can partial reproductive isolation certainly forest in the Sri Lanka’s moist area.
Quoting cross-virility in the several spatial scales inside a herb species’ variety lets understanding of the significance of genetic incompatibility and inbreeding and you may outbreeding despair significantly less than sheer standards. Within reduced spatial scales, the brand new limited seeds dispersal feature of several herbs is trigger relatedness among near-natives in absolute communities. Where nearby herbs is actually relevant, mating anywhere between residents (we.elizabeth., biparental inbreeding; Uyenoyama, 1986) can result in reduced reproductive fitness because of inbreeding anxiety otherwise hereditary incompatibility between mates. While you are models out of okay-scale genetic relatedness were found for a number of herbaceous variety (age.g., Epperson and Clegg, 1986; Waser, 1987; Schoen and Latta, 1989), to have woody species, such angiosperms, analysis to the within this-society genetic structure is restricted. Particular studies have revealed spatial clustering from mature genotypes (or alleles) when you look at the creature-pollinated tree trees (Acer saccharum-Perry and you will Knowles, 1991; Swartzia simplex-Hamrick, Murawski, and you will Nason, 1993; Quercus rubra-Sork, Huang, and you may Wiener, 1993; Quercus laevis-Berg and you can Hamrick, 1995; Cordia alliodora-Boshier, Pursue, and Bawa, 1995), while others have failed to support the newest presumption regarding hereditary relatedness one of nearby people (Psychotria nervosa-Dewey and you will Heywood, 1988; Alseis blackiana and you may Platypodium elegans-Hamrick, Murawski, and you can Nason, 1993). Despite patterns away from relatedness, mating might be limited to local neighborhoods when you look at the herbaceous types (Levin and you may Kerster, 1974; Endler, 1979; Waser and you may Speed, 1983) and also in woody kinds, particularly if flowering grownups try clustered (Linhart, 1973; Stacy mais aussi al., 1996). The potential for biparental inbreeding despair into the absolute populations has been showed for many herbaceous and you will coniferous tree types (Coles and you can Fowler, 1976; Park and you will Fowler, 1982; Levin, 1984; Schemske and you can Pautler, 1984; McCall, Mitchell-Olds, and you can Waller sites de rencontres pour les passionnés de tatouage, 1991; Heywood, 1993; Waser and you can Rate, 1994; Trame, Coddington, and you will Paige, 1995; Byers, 1998). Hardly any is known, however, out of biparental inbreeding anxiety into the pure populations out-of woody angiosperms.