Cross-virility in two exotic tree variety: evidence of inbreeding despair inside populations and you may hereditary divergence one of communities †
The author thank you so much S. Gunatilleke and you can N. Gunatilleke on Department of Botany, College or university regarding Peradeniya to possess advice and logistic assistance; brand new Tree Agencies away from Sri Lanka getting permission so you can conduct this really works inside Sinharaja World Community Website; this new Botany Agency, School off Peradeniya to be used of their establishment; S. Harischandran, H. Gamage, and you may Yards. Gunadasa to own assistance with hands-pollinations; and you may S. Harischandran and A good. Anura getting tending greenhouse seedlings. P. Ashton, K. Bawa, Letter. Gunatilleke, J. Hamrick, L. Kaufman, and you will J. Mitton provided beneficial conversations; P. Ashton, S. Dayanandan, and you will C. Schneider stated to the prior to drafts; and you can B. Wieninger helped with the numbers. This really works was served in part of the money from the newest Maintenance, Dinner, & Health Basis, Inc.
Abstract
Understanding the spatial designs regarding get across-virility inside the pure bush populations productivity trick insight into biparental inbreeding depression, isolation because of the point, and, sooner or later, speciation. Around three grownups all of several warm forest varieties (Syzygium rubicundum and you will Shorea cordifolia) had been each entered that have four conspecific pollen donors anywhere between worry about so you can woods occurring inside independent tree supplies (twelve and you can thirty-five kilometres distance having S. rubicundum and you can Sh. cordifolia, respectively). Cross-fertility was estimated given that fruit place, seed products germination, and you can seedling survivorship and you may top on step 1 year. Technique of very get across-fertility steps increased gradually having outcrossing point, peaking on step 1–2 km having S. rubicundum and step 1–ten kilometres to own Sh. cordifolia, following declining at anywhere between-forest crosses. Although not, seed products germination and you may seedling height to have Sh. cordifolia recommended crossbreed energy between-forest crosses. New suggest physical fitness price of nearby-neighbors mating prior to crossing with more faraway neighbors try forty five% getting S. rubicundum and 0% to have Sh. cordifolia. New imply physical fitness cost of between-tree crosses try 52% and you can 70% towards one or two varieties. Crossing outcomes into the exercise reduced between the level from fruits lay and you will step one-yr-old seedlings. Efficiency mean a powerful potential for inbreeding anxiety in this tree tree communities and limited reproductive isolation certainly one of woods when you look at the Sri Lanka’s moist region.
Quoting cross-fertility within several spatial scales contained in this an extract species’ variety allows understanding of the necessity of genetic incompatibility and you may inbreeding and you may outbreeding depression significantly less than natural requirements. In the shorter spatial scales, brand new minimal vegetables dispersal feature many plant life will be result in relatedness certainly near-natives within the sheer populations. Where surrounding herbs is actually related, mating ranging from natives (i.age., biparental inbreeding; Uyenoyama, 1986) could lead to quicker reproductive fitness due to inbreeding depression or hereditary incompatibility between friends. If you are models away from fine-scale hereditary relatedness was in fact revealed for a number of herbaceous species (age.grams., Epperson and you may Clegg, 1986; Waser, 1987; Schoen and you can Latta, 1989), getting woody varieties, instance angiosperms, investigation into in this-population genetic structure are limited. Specific studies have found spatial clustering out of mature genotypes (otherwise alleles) inside the creature-pollinated forest woods (Acer site de rencontre gratuit pour célibataires polyamoureux saccharum-Perry and you can Knowles, 1991; Swartzia simplex-Hamrick, Murawski, and Nason, 1993; Quercus rubra-Sork, Huang, and you will Wiener, 1993; Quercus laevis-Berg and you may Hamrick, 1995; Cordia alliodora-Boshier, Pursue, and you will Bawa, 1995), although some have failed to help with this new assumption off genetic relatedness certainly one of surrounding grownups (Psychotria nervosa-Dewey and you can Heywood, 1988; Alseis blackiana and you can Platypodium elegans-Hamrick, Murawski, and you may Nason, 1993). No matter what activities away from relatedness, mating is oftentimes limited to local neighborhoods in the herbaceous types (Levin and you will Kerster, 1974; Endler, 1979; Waser and you may Rates, 1983) along with woody kinds, especially if flowering grownups is actually clustered (Linhart, 1973; Stacy ainsi que al., 1996). The chance of biparental inbreeding despair inside pure communities has been showed for a number of herbaceous and you will coniferous tree species (Coles and Fowler, 1976; Park and you will Fowler, 1982; Levin, 1984; Schemske and you may Pautler, 1984; McCall, Mitchell-Olds, and you will Waller, 1991; Heywood, 1993; Waser and you can Speed, 1994; Trame, Coddington, and you can Paige, 1995; Byers, 1998). Little is known, however, of biparental inbreeding depression when you look at the sheer populations off woody angiosperms.