Abstract Microsatellite primers pairs were developed for the Neotropical tree Roupala montana var. brasiliensis for use in studies on genetic diversity, mating system, and gene flow. Forty-two primer pairs were developed, resulting in 27 polymorphic loci, with two to 27 alleles per locus. The primer pairs were validated against 34 R. montana var. brasiliensis adult trees from four populations. The observed (H o) and expected (H e)heterozygosities ranged among loci from 0.061 to 0.930 (mean of 0.544) and from 0.116 to 0.950 (mean of 0.700), respectively. Null alleles were observed for ten loci. No genotypic linkage disequilibrium was detected in any pair of loci. This set of loci is suitable for population genetic studies of the species.

Peach palm (Bactris gasipaes) is cultivated by many indigenous and traditional communities from Amazonia to Central America for its edible fruits, and is currently important for its heart-of-palm. The objective of this study was to investigate the mating system of peach palm, as this is important for conservation and breeding. Eight microsatellite loci were used to genotype 24 open-pollinated progenies from three populations of the Pampa Hermosa landrace maintained in a progeny trial for genetic improvement. Both the multi-locus outcrossing rates (0.95 to 0.99) and the progeny level multi-locus outcrossing rates (0.9 to 1.0) were high, indicating that peach palm is predominantly allogamous. The outcrossing rates among relatives were significantly different from zero (0.101 to 0.202), providing evidence for considerable biparental inbreeding within populations, probably due to farmers planting seeds of a small number of open-pollinated progenies in the same plot. The correlations of paternity estimates were low (0.051 to 0.112), suggesting a large number of pollen sources (9 to 20) participating in pollination of individual fruit bunches. Effective population size estimates suggest that current germplasm collections are insufficient for long-term ex situ conservation. As with most underutilized crops, on farm conservation is the most important component of an integrated conservation strategy.

The mating system and genetic diversity were studied in a natural population of Myracrodruon urundeuva originating from 30 open-pollinated trees at the Paulo de Faria Ecological Station, SP, Brazil. The progenies were planted on the Teaching and Research Farm of the Ilha Solteira Engineering School, UNESP. Using the fAFLP molecular marker, eleven loci were selected to study the mating system. The mating system was analyzed using the multilocus mixed-mating model. The estimates of genetic divergence between pollen and ovule allele frequencies were significant for eight loci, suggesting nonrandom outcrossing. The estimates of the multilocus outcrossing rate revealed that M. urundeuva possesses a mating system with a predominance of outcrossing events (theta = 0.940 ± 0.086). The estimates of coancestry among plants within progenies (theta = 0.185) was higher than that expected for half-sib progenies (0.125) and the indirect estimate of the correlation of outcrossed paternity within progeny arrays (r p) was 0.403, suggesting that progenies have a high proportion of full-sibs. Result analysis suggests the need for the application of biometric models that take into account deviations from random outcrossing in the estimations of genetic parameters for quantitative traits and the need for retaining large sample sizes in order to preserve genetic variability.

O objetivo do presente trabalho foi avaliar a taxa de cruzamento de uma população de Chorisia speciosa por marcadores isoenzimáticos. Foram amostradas sementes de polinização aberta em 28 árvores e tecidos foliares em 53 árvores adultas de uma população de C. speciosa localizada na Estação Ecológica de Bauru, São Paulo, Brasil. Observou-se 18 alelos distribuídos em sete locos polimórficos. O índice de fixação (<img border=0 width=32 height=32 id="_x0000_i1026" src="../../../img/revistas/rbb/v26n1/a11let_f.gif" align=absmiddle>) foi menor nos adultos em relação às progênies, sugerindo seleção contra homozigotos. A estimativa da taxa de cruzamento multilocos (<img border=0 width=32 height=32 id="_x0000_i1027" src="../../../img/revistas/rbb/v26n1/a11let_tm.gif" align=absmiddle>) foi de 0,816, revelando que a espécie é de reprodução mista, predominantemente alógama. Foi detectada heterogeneidade no conjunto de pólen dos cruzamentos, indicando que os mesmos não foram aleatórios. Em concordância, a correlação de paternidade (<img border=0 width=32 height=32 id="_x0000_i1028" src="../../../img/revistas/rbb/v26n1/a11let_rp.gif" align=absmiddle>) revelou que as progênies são constituídas por uma alta proporção de irmãos completos (71,4%). Foram também detectados cruzamentos entre aparentados na população (5,6%), sugerindo uma possível estruturação espacial em famílias.

This study aims to analyse by isozymes the outcrossing rate in a Chorisia speciosa population. Thus, open-pollinated seeds from 28 trees and leaves from 53 adult trees were sampled in a C. speciosa population at the Bauru Ecological Station, São Paulo State, Brazil. Eighteen alleles were observed distributed in seven polymorphic loci. The fixation index (<img border=0 width=32 height=32 id="_x0000_i1030" src="../../../img/revistas/rbb/v26n1/a11let_f.gif" align=absmiddle>) was smaller in adult trees than in families, suggesting selection against homozygous. The multilocus outcrossing estimate (<img border=0 width=32 height=32 id="_x0000_i1031" src="../../../img/revistas/rbb/v26n1/a11let_tm.gif" align=absmiddle>) was 0.816, revealed that this species is a mixed mating system, predominantly alogamous. Heterogeneity of pollen pool was observed in outcrossing individual tree indicating that mating were not random. The paternity correlation (<img border=0 width=32 height=32 id="_x0000_i1032" src="../../../img/revistas/rbb/v26n1/a11let_rp.gif" align=absmiddle>) revealed that families are constituted of a high proportion of full sibs (71.4%). There was also detection of crossing among relatives in population (5.6%), indicating the possibility of family structure within population.

The aim of this research was to study the mating system of a natural population of Theobroma grandiflorum (cupuassu) from Nova Ipixuna, Pará state, using microsatellite markers. Eight polymorphic microsatellite loci were analyzed in eight families, each represented by 10 six-month old seedlings derived from open-pollinated pods. The estimation for the multilocus outcrossing rate (<img border=0 id="_x0000_i1026" src="../../img/revistas/gmb/v26n3/a25img01.gif" align=absmiddle>m = 1.0) and individual outcrossing rate (<img border=0 id="_x0000_i1027" src="../../img/revistas/gmb/v26n3/a25img01.gif" align=absmiddle> = 1.0) for this population suggests that T. grandiflorum may be a perfect outbreeding (allogamous) species. Likewise, for the studied population the estimate for single locus outcrossing rate (<img border=0 id="_x0000_i1028" src="../../img/revistas/gmb/v26n3/a25img01.gif" align=absmiddle>S) was elevated (0.946), but lower than <img border=0 id="_x0000_i1029" src="../../img/revistas/gmb/v26n3/a25img01.gif" align=absmiddle>m, confirming the likely outcrossing character of the species and suggesting the occurrence of 5.4% biparental inbreeding rate (<img border=0 id="_x0000_i1030" src="../../img/revistas/gmb/v26n3/a25img01.gif" align=absmiddle>m - <img border=0 id="_x0000_i1031" src="../../img/revistas/gmb/v26n3/a25img01.gif" align=absmiddle>S). The estimation of genetic divergence (<img border=0 id="_x0000_i1032" src="../../img/revistas/gmb/v26n3/a25img02.gif" align=absmiddle>st) between allelic frequencies in ovules and pollen revealed a deviation from random mating in 75% of the evaluated loci. Likewise, the estimate of correlation of paternity (<img border=0 id="_x0000_i1033" src="../../img/revistas/gmb/v26n3/a25img03.gif" align=absmiddle>P = 0.930) and the mean coefficient of co-ancestrality within families (<img border=0 id="_x0000_i1034" src="../../img/revistas/gmb/v26n3/a25img04.gif" align=absmiddle>XY = 0.501) indicated that the outcrossings were predominantly correlated, and the offspring were full-sibs. These results suggested that for this particular population of T. grandiflorum, the sampling strategy for genetic conservation and breeding should adopt specific models for families derived from correlated outcrossing (full-sibs) and not the ones usually adopted in classic outcrossing species breeding programs (half-sibs).