Abstract Pinus greggii has potential for inclusion in temperate zone breeding programs around the world as it is frost resistant and produces high yields for pulp production. This study estimates the genetic parameters for two P. greggii progeny tests established in Telêmaco Borba, Paraná, Brazil. We evaluated diameter at breast height (DBH) and total height (H) at seven and nine years of age. The narrow-sense heritability ( h i 2) ranged from 0.225 (H, 7 years) to 0.515 (H, 9 years). The genetic correlation was high for all traits, reaching up to 0.91 between traits and 0.94 between ages. In addition, the results show the presence of Genotype x Environment interaction, and as such, the most productive and stable progeny were identified based on the Harmonic Mean of the Relative Performance of Genetic Values (MHPRVG) values. These population has genetic materials that are superior in terms of both DBH and H compared to the control and to P. greggii materials analyzed internationally. Our results contribute to the literature by providing further genetic information on this species, while also demonstrating the implications of thinning for genetic gains and effective population size.

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.

ABSTRACT Rhizophora mangle L. (Rhizophoraceae) grows on aerial roots, which emerge above the water level, giving stands of this tree the characteristic “mangrove” appearance. To produce in situ and ex situ information for genetic conservation programs for this species, we investigated the genetic diversity and mating system of one R. mangle population. We sampled 30 adult trees and a total of 349 seeds in Northern Brazil. We genotyped all adult trees and seeds with four microsatellite loci. The average fixation index was -0.222 for adult trees and 0.030 for seeds. The multilocus outcrossing rate (t m =0.921) was significantly lower than unity (1.0). There was no substantial evidence of null alleles nor genotypic disequilibrium among the loci. The combined power to exclude the first parent probability was 0.921. The average coancestry coefficient (=0.180) was similar to that expected for half-sib progenies (=0.125). Thus, the number of adult trees necessary for seed collection to obtain progeny arrays with an effective size of 150 was estimated to be 62. In conclusion, this study produced important information for the management and conservation of R. mangle and will contribute to conservation and management programs for this species.

Abstract The aim of this study was to develop a shoot regeneration protocol for Tectona grandis by examining the effects of pretreatments, regeneration culture medium, adventitious rooting, and acclimatization. The best organogenic potential was achieved when hypocotyls and cotyledonary segments from seedlings germinated on a medium containing TDZ, were cultured for four weeks on MS medium supplemented with BAP/GA3. With TDZ pretreatment during seed germination, up to 70% of the cotyledonary segments (0.5 TDZ pretreatment and 1.0 BAP + 0.5 GA3 during regeneration, mg L-1) and 60% of the hypocotyl explants (0.1 TDZ pretreatment and 1.0 BAP + 0.5 GA3 during regeneration, mg L-1) resulted in shoot regeneration. Finally, 65% of the regenerated shoots rooted, of which 60% were successfully acclimatized ex vitro. Our protocol increases regeneration efficiency for teak and it can serve as a platform for genetic transformation to improve this important tree species.