Cross-virility in two warm forest variety: proof of inbreeding despair in this communities and you may hereditary divergence one of populations †
The writer many thanks S. Gunatilleke and you may N. Gunatilleke during the Department out of Botany, School from Peradeniya to have information and you will logistic assistance; the brand new Tree Department regarding Sri Lanka to have permission so you’re able to make this works within the Sinharaja Globe Tradition Webpages; the latest Botany Agency, University off Peradeniya for usage of their business; S. Harischandran, H. Gamage, and you will Meters. Gunadasa getting help with give-pollinations; https://www.datingranking.net/it/incontri-etero/ and you will S. Harischandran and A great. Anura to own tending greenhouse seedlings. P. Ashton, K. Bawa, N. Gunatilleke, J. Hamrick, L. Kaufman, and you can J. Mitton offered helpful talks; P. Ashton, S. Dayanandan, and you will C. Schneider mentioned to the earlier drafts; and B. Wieninger helped into the data. So it work was served to some extent from the funds from the fresh Conservation, Food, & Fitness Foundation, Inc.
Knowing the spatial habits regarding get across-fertility in the absolute bush communities productivity trick understanding of biparental inbreeding anxiety, isolation from the range, and you can, in the course of time, speciation. About three adults each of one or two exotic tree kinds (Syzygium rubicundum and you may Shorea cordifolia) was per crossed having five conspecific pollen donors ranging from notice so you can trees going on inside the independent forest reserves (twelve and you can 35 km length for S. rubicundum and Sh. cordifolia, respectively). Cross-fertility is estimated since the good fresh fruit place, seed products germination, and seedling survivorship and you will height at 1 year. Means of very cross-virility strategies improved gradually having outcrossing distance, peaking within step one–dos kilometer getting S. rubicundum and you will step one–ten km having Sh. cordifolia, after which decreasing at the between-forest crosses. Yet not, vegetables germination and seedling peak to have Sh. cordifolia advised crossbreed energy between-forest crosses. The latest imply exercise price of nearby-neighbor mating relative to crossing with more distant natives is forty five% to possess S. rubicundum and 0% to own Sh. cordifolia. The fresh suggest exercise price of between-tree crosses are 52% and you will 70% into a few variety. Crossing consequences on the exercise decreased within amount regarding fruits put and 1-yr-dated seedlings. Results imply a robust possibility of inbreeding anxiety within this tree tree populations and you can limited reproductive separation certainly one of forests into the Sri Lanka’s moist region.
Estimating cross-fertility from the numerous spatial balances within this a plant species’ assortment lets insight into the significance of hereditary incompatibility and you will inbreeding and you may outbreeding despair less than natural requirements. At less spatial scales, the brand new limited seeds dispersal trait many plant life is produce relatedness one of close-neighbors within the absolute communities. Where neighboring flowers is actually associated, mating ranging from neighbors (i.e., biparental inbreeding; Uyenoyama, 1986) can result in quicker reproductive exercise on account of inbreeding depression or hereditary incompatibility between mates. When you find yourself patterns out of fine-scale genetic relatedness were found for many herbaceous species (e.grams., Epperson and you may Clegg, 1986; Waser, 1987; Schoen and you may Latta, 1989), having woody species, for example angiosperms, research with the in this-population hereditary design is limited. Particular research has shown spatial clustering away from adult genotypes (or alleles) for the animal-pollinated forest trees (Acer saccharum-Perry and you will Knowles, 1991; Swartzia simplex-Hamrick, Murawski, and you may Nason, 1993; Quercus rubra-Sork, Huang, and you will Wiener, 1993; Quercus laevis-Berg and Hamrick, 1995; Cordia alliodora-Boshier, Pursue, and you can Bawa, 1995), although some failed to support the assumption out of hereditary relatedness one of neighboring people (Psychotria nervosa-Dewey and you will Heywood, 1988; Alseis blackiana and Platypodium elegans-Hamrick, Murawski, and you will Nason, 1993). Despite habits away from relatedness, mating is often limited to local areas within the herbaceous kinds (Levin and you may Kerster, 1974; Endler, 1979; Waser and you may Price, 1983) and in woody species, especially if blooming grownups is clustered (Linhart, 1973; Stacy et al., 1996). The potential for biparental inbreeding anxiety in natural communities could have been presented for a lot of herbaceous and you will coniferous tree varieties (Coles and Fowler, 1976; Park and you may Fowler, 1982; Levin, 1984; Schemske and you may Pautler, 1984; McCall, Mitchell-Olds, and you will Waller, 1991; Heywood, 1993; Waser and you may Rate, 1994; Trame, Coddington, and you may Paige, 1995; Byers, 1998). Little is known, however, out of biparental inbreeding anxiety from inside the pure populations out of woody angiosperms.