ABSTRACT. Native of the Amazon, the nanche (Byrsonima crassifolia) is a fruit cultivated by family farmers and used in cooking; as such, it represents an opportunity for regional agribusiness. The Embrapa Eastern Amazon set up an active germplasm bank (BAG) consisting of 22 accessions sampled in 11 municipalities of Pará State. Due to its economic potential, there is an interest to advance the genetic breeding program of this species. The aim of this study was to characterize the BAG nanche collection using inter-simple sequence repeat (ISSR) markers. Accessions were genotyped using 23 preselected ISSR primers resulting in 109 amplified polymorphic and 51 monomorphic bands. With eight polymorphic bands each, the most polymorphic primers were UBC 809 and UBC 848. An unweighted pair-group method with arithmetic average cluster analysis based on Jaccard's coefficient indicated that the individuals clustered into two distinct groups. Accessions Igarapé Açu-2 and Augusto Corrêa-Pl 1 were most similar. The genetic dissimilarity values ranged from 0.10 to 0.59. We conclude that the ISSR markers were efficient in detecting polymorphisms in the nanche accessions, and that it is possible to infer the genetic variability among accessions of the collection. This demonstrate the importance of using molecular markers in poorly studied species and the advantages that this information can bring to the genetic improvement of such species.

The use of more than one control technique can maximize the reduction of the damages caused by the fungus Asperisporium caricae causal agent of the black spot in the papaya crop. The objective of this work was to evaluate the sensitivity of the fungi Hansfordia pulvinata and Acremonium spp. to alternative products with potential for use in the control of the black-spotted ptarmigan. Three isolates of Acremonium spp. (A-598, A-602 and A-617) and an isolate of H. pulvinata (H-611) were grown in BDA medium containing Agro-Mos  , Bion  , Ecolife  , Hortifospk  , Matriz G  , Vitaphol  separately. The Amistar 500WG  fungicide was used as a positive control and pure BDA as a negative control. The toxicity of the tested products was determined based on the values of the biological index, derived from the means of mycelial growth, sporulation and germination of conidia, in each experimental unit. In this way it was possible to select the products classified as compatible for all isolates, and to test them in vivo. In the greenhouse, only the isolates and isolates with selected products, were applied in papaya plants with foliar symptoms of black-spotted. The incidence of leaves with hyperparasites and the percentage of black-painted lesions colonized by the tested isolates were evaluated. Thus, the H-611 isolate proved to be compatible with most of the alternative products tested, except with Hortifos  . Bion  and Matrix  products were compatible with all tested isolates and could be used in conjunction with Acremonium spp. and H. pulvinata to control the papaya black spot, since these products did not present toxicity on the hyperparasitic fungi.

Estimation of genetic parameters such as genetic variability of germplasm allows inferring genotype-enviromental interaction for a given variable. The information is important for the process of choosing the variables to be applied to the superior genotype selection. This study aimed at evaluating characteristics related to genetic resistance of papaya to black spot during time testing, as well as estimating genetic parameters associated with some characteristics. The experiment was carried out in RCBD design at Agua Limpa farm, Espirito Santo state, Brazil, using six genotypes: ‘STZ-03’, ‘SS-PT’, ‘Golden’ (‘Solo’ group) ‘Maradol’ (‘Formosa’ group) ‘STA-04’ ‘STA-10’ (landraces), and four repetitions. The 6 treatments were arranged in single row, spacing 2 m between rows and 1.5 m within plants. Nine evaluations were performed during 9 months. We quantified plants on a monthly basis for the characters such as symptom appearance of black spot (FS) on leaves; the incidence of leaves with black spot symptoms (IBS); the severity of black spot on the fifth leaf (SBS5F) and on the leaf with axil attached to the first open flower (SBSFO). By means of the evaluation values, we built a Boxplot graphic to characterize the magnitude of the variables and to describe the dispersion of the data set throughout the evaluations. Analysis of variance, genetic parameter estimate and comparative test of mean were also conducted. The Boxplot graphic allowed classification and magnitude of the variables and described the dispersion of the data set during evaluations. The results showed that SBS5F and the SBSFO were the characteristics that generated reliable results to select genotypes in all evaluations. They showed high H² (Coefficient of genotypic determination), CVg (Coefficient of genotypic variance), CVr (Coefficient of relative variance) and AS (Selective accuracy). The months July, August, September and October showed higher representativeness to evaluate attributes related to resistance to black spot in papaya leaves.

Southern corn leaf blight (SCLB) is one of the most important corn leaf diseases. Appropriate management strategies and the use of resistant cultivars allow disease control. Therefore, knowing the aspects related to the pathogen and the response of hosts makes it possible to design efficient strategies for selecting genotypes resistant to this disease. In this sense, the objective was to carry out the Bipolaris maydis isolate characterization, evaluating the pathogenicity in different popcorn lines and the symptoms generated in the host after inoculation. The isolate characterization consisted of the macromorphological evaluation of the colonies and the micromorphological evaluation of the conidia in the PDA medium. An experiment was carried out in a greenhouse to evaluate the pathogenicity of the isolate, using 20 inbred lines of popcorn in a randomized block design with four replicates. Inoculation was carried out by spraying leaves, with a suspension containing 1.0 x 104 conidia.ml-1 of the CF/UENF 501 isolate of B. maydis. An incidence assessment and three assessments of disease symptom severity were performed, with seven days intervals between evaluations. The morphological characterization data of the isolate were analyzed using descriptive statistics, and for disease severity, the linear regression model was applied the first-degree model. The variance analysis was performed for the linear and angular coefficients obtained for each treatment. When a difference was found, the Scott-Knott clustering algorithm at 5% significance was applied. The isolate had gray-green colonies, a cottony appearance, and an irregular shape. The lines L353, L354, and L624 show more resistance at the beginning and throughout the evaluations. The high virulence of the CF/UENF 501 isolate made it possible to differentiate the lines in terms of disease intensity and the pattern of symptoms presented.

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