Capsicum baccatum is one of the main pepper species grown and consumed in South America. In Brazil, it is commonly cultivated by family farmers, using mostly the genotypes bishop's hat genotypes (locally cambuci) and red chili pepper (dedo-de-moça). This study had the objective of characterizing 116 C. baccatum accessions from different regions of Brazil, based on morphological fruit descriptors and AFLP (Amplified Fragment Length Polymorphisms) markers. Broad phenotypic variability among the C. baccatum accessions was detected when using morphological fruit descriptors. The Ward modified location model (Ward-MLM) discriminated five groups, based mainly on fruit shape. Six combinations of AFLP primers detected polymorphism in 97.93% of the 2466 identified bands, indicating the high genetic variability in the accessions. The UPGMA coincided with the Bayesian clustering analysis and three large groups were formed, separating the wild variety C. baccatum var. praetermissum from the other accessions. There was no relation between genetic distance and geographical origin of the accessions, probably due to the intense exchange of fruits and seeds between farmers. Morphological descriptors used together with AFLP markers proved efficient in detecting the levels of genetic variability among the accessions maintained in the germplasm collections. These results can be used as an additional source of helpful information to be exploited in C. baccatum breeding programs.

Anthracnose, caused by Colletotrichum spp., is one of the most common diseases affecting sweet pepper and chilli pepper production worldwide, especially in tropical and subtropical zones. This disease results in severe fruit damage both pre‐ and postharvest. The development of resistant cultivars is the most effective strategy for disease control, which requires knowing the genetic basis of resistance. In this study, we analysed the inheritance of resistance of Capsicum annuum to Colletotrichum scovillei at two fruit development stages. The ripe and unripe fruits were inoculated by conidia suspension, and anthracnose severity was evaluated for 8 days using a score scale. It was found that the inheritance of resistance has independent expression in ripe and unripe fruits. In both cases, two main genes are responsible for resistance with polygenic effects. Genetic control, with a quantitative aspect, is more affected by dominance than the additive effects, in both fruit development stages of C. annuum.

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.

The evaluation of genetic diversity among the accessions of a germplasm collection results in information about promising materials suitable for breeding programs. Thus, the goal of this work was to characterize Capsicum baccatum accessions from different Brazilian regions, based on morphological, biochemical and molecular traits, aiming to support chili pepper breeding programs. The fruits were morphologically characterized based on fruit length, diameter, fresh mass and pericarp thickness, and biochemically analyzed for their content in ascorbic and phenolic acids, flavonoid and antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) and ferric reducing antioxidant power (FRAP) assays. All phenotypic traits showed significant differences among the chili pepper accessions, indicating a wide variability.The fruits were also characterized using amplified fragment length polymorphism (AFLP) molecular markers. The combination of six AFLP primers resulted in 1117 bands, 1033 of which were polymorphic. Divergence between accessions was estimated by the Ward's hierarchical agglomerative clustering method, resulting in three and two clusters for fruit phenotypic traits and molecular data, respectively. In Bayesian analysis, molecular data also clustered the accessions in two groups. There was no association between the phenotypic descriptors and AFLP markers, indicating that both characterizations are important to better understand the genetic variability. Furthermore, it was not possible to group the accessions solely based on their origin for neither phenotypic descriptors and AFLP markers. The accessions G1, G5, G6, and G20 showed interesting characteristics and can be used in breeding programs, aiming the development of Capsicum spp. cultivars with desirable morphological and biochemical traits.

Although stalk and ear rot is a major disease affecting corn plants, little is known regarding the genetic variability of Stenocarpella maydis, its main causal agent. In this study, we evaluated inter-simple sequence repeat (ISSR) primers for analysis of genetic variability of the pathogen. For DNA analysis, six isolates of S. maydis were amplified using 42 ISSR primers. Polymorphic information content (PIC), marker index (MI), and resolving power (RP) were calculated for all primers. Of the 42 primers, 50 % showed high-quality amplification products. The average polymorphism was 90.4 %, and the average similarity among the isolates was 33 %.