Individual, fruit, and annual variation in correlated mating in a Genipa americana population

Abstract

In this paper, we use six microsatellite loci to examine a spatially isolated population of Genipa americana in relation to mating system variation at the level of individual and among and within fruits, over two reproductive events. For our analysis, we sampled hierarchically among and within fruits open-pollinated seeds collected from 13 seed trees during the reproductive event in 2010 and 12 seed trees in 2011. The rate of mating among relatives (1-ts) was significantly greater than zero and different between the investigated reproductive events, indicating that some seeds are inbred. The estimate of fixation index (Fo) was significantly higher than zero for seeds from both reproductive events (2010: Fo = 0.258; 2011: Fo = 0.294), confirming that seeds present inbreeding, probably originated from mating among full-sibs. The multilocus paternity correlation within fruits (rp(w)) and among fruits (rp(a)) varied among seed trees and reproductive events. The rp(w) was significantly higher than rp(a) in both reproductive events, suggesting that it is more likely to find full-sibs within fruits (2010: 36.4%; 2011: 72.4%), than among fruits (2010: 18.9%; 2011: 12.8%). Due to the presence of inbreeding, mating among relatives and correlated mating, the within families coancestry coefficient (Θ) was higher and the variance effective size (Ne) lower than expected in open-pollinated families from panmictic populations (Θ = 0.125, Ne = 4). In practical terms for conservation programs, our results show the need to collect seeds from at least 60 seed trees to retain progeny arrays with a total effective size of 150.

Mating system variation among populations, individuals and within and among fruits in Bertholletia excelsa

“…This result is important to guide strategic seed collection, recommending the gathering of a larger number of fruits per tree as will be present in section Recommendation for conservation and reforestation. Our results are in line with other studies of mating system in insect pollinated tree species, where higher correlated mating within than among fruits have also been reported (SAMPSON, 1998;SILVA et al, 2011;FERES et al, 2012;MANOEL et al, 2015;TAMBARUSSI et al, 2015). However, the effective number of pollen donors varied from tree to tree and ranged from 1.0 to 13.3 within fruits and from 3.5 to 24.4 among fruits, indicating that some seed trees received pollen from fewer pollen donors than others, and that the probability of finding full-sibs within and among fruits was higher in some seed trees.…”

Research Article Hierarchical outcrossing among and within fruits in Bertholletia excelsa Bonpl. (Lecythidaceae) open-pollinated seeds

“…Our ep N results at population level are similar to those recorded for other populations (4.5) distributed in natural forests (Wadt et al, 2015). The paternity correlation within fruits ( ) (w p r ) was higher than between fruits ( ) (a p r ) at population level ( ) (w p r = 0.67, ) (a p r = 0.18), as well as at individual level (Table 1) is also reported in many studies involving insect-pollinated tree species (Muona et al, 1991;Sampson, 1998;Quesada et al, 2001;Tamaki et al, 2009;Silva et al, 2011;Manoel et al, 2015;Tambarussi et al, 2015).…”

Long‐distance pollen and seed dispersal and inbreeding depression in Hymenaea stigonocarpa (Fabaceae: Caesalpinioideae) in the Brazilian savannah

“…Paternity correlation was similar within ( r p(w) ) and among ( r p(a) ) fruits, which indicates the probability of finding full‐sibs within and among fruits; however, at the level of individual trees, the r p(w) values were generally lower than the r p(a) values. Higher r p(w) values than r p(a) values have been reported for other tropical tree species (Giustina et al., ; Manoel et al., ; Quesada et al., ; Silva et al., ; Tambarussi et al., ; Wadt et al., ). Thus, as we also found self‐fertilization in both populations, and families presented mixtures of self‐sibs, half‐sibs, full‐sibs, and self‐half‐sibs, with inbred selfed offspring and substantial proportions of half‐sibs and full‐sibs presenting inbreeding due to the detected mating among related individuals.…”

“…These analyses were carried out using FSTAT software (Goudet, 2002). However, as the F estimated for offspring can be biased due to the overestimation of gene frequencies of maternal alleles (each plant within a family receives at least one maternal allele), this index was estimated as described in Manoel et al (2015). To test if the estimated indices were significantly different between samples, we used the unpaired t test.…”