The relationship ranging from outcrossing length and you may collective physical fitness was not extreme (quadratic regression: F

The relationship ranging from outcrossing length and you may collective physical fitness was not extreme (quadratic regression: F | Shlomtz

For two forest variety during the Sri Lanka’s moist region forests, good fresh fruit place more than doubled having outcrossing point, peaking from the intermediate-distance within this-forest crosses (1–ten km based variety). During the crosses between trees consuming separate tree reserves, but not, fruits put are significantly reduced (or almost so) for variety. Alternatively, seed products germination and you can seedling level at 1 yr for Sh. cordifolia advised crossbreed vigor in-between-forest crosses. The results regarding nearby-next-door neighbor mating ranged among woods and species; new imply exercise cost of rencontres hétérosexuelles nearest-next-door neighbor mating in accordance with mating that have meagerly more distant natives are 45% getting S. rubicundum and 0% to own Sh. cordifolia. Conversely, the fresh new physical fitness outcomes of between-tree crossing were good-sized both for species (52 and you can 70% prior to within this-tree crosses for similar a couple of variety). Crossing effects decreased involving the amount of fresh fruit put and you will step one-yr-dated seedling proportions; just the former was extreme for both varieties. Efficiency mean a powerful possibility of biparental inbreeding despair within tree tree populations and you can limited reproductive separation one of trees consuming the rest tree reserves from inside the Sri Lanka’s damp area.

Inbreeding despair is often quoted because the an inescapable outcome of anthropogenic interference so you can tropical woods (e.g., forest fragmentation, logging), where concept predicts you to definitely typical mating habits contained in this currently low-density forest communities are moved on so you can favor small-length crosses. Up until now, however, the results out-of elevated close-neighbors mating to possess inhabitants fitness when you look at the tropical woods enjoys yet so you can be quantified empirically. A few fundamental questions become treated try: Would adults prevent maturing vegetables based on close-neighbors crosses and you will, or even, just how complement is actually close-neighbor-derived progeny relative to anyone else? This study analyzes the effects of near-next-door neighbor mating in 2 tropical tree species individually using fitness reviews off crosses ranging from nearby neighbors that have crosses related to way more distant friends.

Shorea cordifolia (Dipterocarpaceae) was a locally abundant head cover kinds you to vegetation greatly during the unusual supra-annual times (I. A good. U. Letter. Gunatilleke et al., unpublished investigation). Plant life of species are white and quick-resided, together with winged fresh fruit is actually spread from the breeze otherwise gravity. For its very limited seeds dispersal, genetic relatedness one of near natives in the pure forest is anticipated in order to feel large. In logged tree at Sinharaja, Sh. cordifolia always takes place in clumps of ?5–20 people, intermixed having shorter stems (private observation).

Studies analysis

For both species, within-treatment variation among maternal trees in fruit set was substantial for all outcrosses involving pollen donors within Sinharaja Reserve. In contrast, variation in fruit set rate was very low for between-forest crosses (Fig. 2). For Sh. cordifolia, fruit set for the distant between-forest treatment ranged from only 0.5 to 0.6% and was significantly lower than the mean fruit set rate for all within-forest outcrossing treatments combined (mean = 2.71%, Fstep one,58 = 9.94, P < 0.0003). For S. rubicundum, mean fruit set for the distant between-forest treatment (2.67%) was low relative to mean fruit set rate for all within-forest outcrossing treatments combined (mean = 5.97%). The difference was nearly significant (Fstep one,58 = 3.78, P < 0.06).

For Sh. cordifolia, cumulative fitness was maximum at both the distant neighbor and distant within-forest treatments (Fig. 5). Peak cumulative fitness observed for these intermediate crossing treatments was 2 and 4.3 times the cumulative fitnesses of the nearest-neighbor and distant between-forest treatments, respectively, although these differences were not significant (Table 3B). dos,8 = 3.70, P = 0.073). Mean cumulative fitness of open-pollinated flowers exceeded that of all other hand-pollination treatments, again likely due to the detrimental effect of the hand-pollination procedure on fruit set in this species. As for fruit set, mean cumulative fitness (relative) of the distant between-forest treatment (mean = 0.12) was significantly lower than that of all within-forest outcrossed classes combined (mean = 0.51, Fstep 1,a dozen = 8.77, P = 0.012).

Near-next-door neighbor crossing feeling

Near-neighbor crossing effects have been demonstrated for a number of coniferous species (Coles and Fowler, 1976; Park and Fowler, 1982, 1984; Latta et al., 1998), but only three studies have yielded evidence of near-neighbor crossing effects in woody angiosperms (Syzygium cormiflorum-Crome and Irvine, 1986; Schiedea spp.-Sakai, Karoly, and Weller, 1989; Eucalyptus globules-Hardner, Potts, and Gore, 1998). In another study suggestive of biparental inbreeding depression, mean fruit set rates were significantly lower for intraspecific crosses <0.5 km distance than for crosses >1 km distance for three subcanopy tree species (Inga spp.) in Costa Rica (Koptur, 1984). In fact, it may be that biparental inbreeding depression is common in natural populations of forest trees, but that estimation of its potential through experimental cross-pollinations has been limited to only a few species due to the obvious difficulty of working in the canopy. To my knowledge, there are no published reports of failed attempts to find near-neighbor crossing effects in natural populations of forest trees.

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