ABSTRACT. Heterosis is a highly relevant phenomenon in plant breeding. This condition is usually established in hybrids derived from crosses of highly divergent parents. The success of a breeder in obtaining heterosis is directly related to the correct identification of genetically contrasting parents. Currently, the diallel cross is the most commonly used methodology to detect contrasting parents; however, it is a time-and cost-consuming procedure. Therefore, new tools capable of performing this task quickly and accurately are required. Thus, the purpose of this study was to estimate the genetic divergence in industrial tomato lines, based on agronomic traits, and to compare with estimates obtained using inter-simple sequence repeat (ISSR) molecular markers. The genetic divergence among 10 industrial tomato lines, based on nine morphological characters and 12 ISSR primers was analyzed. For data analysis, Pearson and Spearman correlation coefficients were calculated between the genetic dissimilarity measures estimated by Mahalanobis distance and Jaccard's coefficient of genetic dissimilarity from the heterosis estimates, combining ability, and means of important traits of industrial tomato. The ISSR markers efficiently detected contrasting parents for hybrid production in tomato. Parent RVTD-08 was indicated as the most divergent, both by molecular and morphological markers, that positively contributed to increased heterosis and by the specific combining ability in the crosses in which it participated. The genetic dissimilarity estimated by ISSR molecular markers aided the identification of the best hybrids of the experiment in terms of total fruit yield, pulp yield, and soluble solids content.

Myrtaceae species play an important role in maintaining the biodiversity of the Atlantic Forest. However, most species of this biome have not been studied. In this work we examined whether microsatellite markers developed for other Myrtaceae species are useful in genetic studies of native species of the Atlantic Forest. We evaluated the transferability of 21 microsatellite markers derived from Eucalyptus sp., Eugenia uniflora, and Melaleuca alternifolia Cheel to eight Atlantic Forest species (Campomanesia xanthocarpa (guabiroba do mato), Campomanesia adamantium, Eugenia uniflora (surinam cherry), Eugenia involucrata (cherry of the Rio Grande), Myrcianthes pungens (guabiju), Plinia cauliflora (jaboticaba), Psidium guajava (guava), and Psidium sp.(araçá) and the utility of the transferred markers in obtaining genetic data from Eugenia uniflora. The transferability of microsatellite primers pairs was high (>52%) in seven of the eight species studied. In three populations of E. uniflora, the transferred primers amplified the same average number of alleles, and the same expected heterozygosity was obtained with species-specific primers. The genetic parameters FIS, Shannon diversity, genetic distance of Nei, FST and FIT, AMOVA, and the PCoA were calculated using data from four transferred microsatellites. Results were similar to those obtained using species-specific primers. Both datasets (from transferred and species-specific primers) indicated that E. uniflora populations of the Atlantic Forest are unstructured and have high genetic diversity. The results of our study indicate that transferability of microsatellite markers is an economic and powerful way to obtain genetic information of Myrtaceae species of the Atlantic Forest, and consequently, will aid in the conservation of these species and the biome.

No abstract

Passiflora coelestis is morphologically and anatomically described from living material as a new species belonging to the section Dysosmia, supersection Stipulata and subgenus and genus Passiflora. The species occurs in Araucaria Moist Forest, a phytophysiognomy of the Atlantic Forest biome. The section has been characterized as one of the most taxonomically complex groups within Passiflora. Passiflora coelestis is related to species within the Dysosmioides group and is similar to P. campanulata, differing mainly in the stipules, petiole, bracts, and corona filaments. The new species is morphologically compared with taxa of the section; moreover, additional anatomic, palynological and molecular data are also discussed with regard to taxonomic classification.