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The biotrophic fungus Hemileia vastatrix is the pathogen responsible for coffee leaf rust, a devastating disease in several coffee-producing countries. Despite the importance of studying the interaction between Coffea and H. vastatrix, a more comprehensive understanding of the mechanisms involved in this pathosystem is necessary. The role of eight candidate genes was analyzed aiming at identifying and validating new important coffee resistance genes and understanding their interaction with H. vastatrix. These genes were identified in the most important sources of coffee resistance, the Híbrido de Timor CIFC 832/2 and CIFC 832/1. Previous works found six resistance genes and, in our research, other two new genes were identified in BAC clones and validated by RT-qPCR during compatible and incompatible interactions between Coffea and H. vastatrix. An interactome approach was performed using Coffea-H. vastatrix and Coffea-Coffea proteins to better understand the biological process and the interaction of the host-pathogen. Two networks of interactions from the compiled data were built focused on candidate genes associated with pre-haustorial resistance (12 and 24 h.a.i) in coffee plants against the pathogen. The results showed, for the first time, differentially expressed proteins (DEPs) positively regulated in the incompatible interaction Coffea-H. vastatrix. These coffee proteins interact with each other and with secreted and/or transmembrane pathogen proteins. The obtained results also show that DEPs found are involved in important plant defense pathways such as pathways associated with the response to wounds, signaling, regulation of the innate immune response and the transmembrane receptor protein serine/threonine kinase pathway. The present work shows the involvement of genes in both pathogen recognition and signaling cascades, which act in pre-haustorial defense mechanisms of HdT coffee. Therefore, the candidate genes analyzed, together with the biological processes elucidated, have the potential to contribute to the development of new control strategies against the fungus H. vastatrix within coffee breeding programs aiming to develop cultivars with durable resistance.

Plant breeding aims to develop cultivars with good agronomic traits through gene recombination and elite genotype selection. To support Coffea arabica breeding programs and assist parent selection, molecular characterization, genetic diversity (GD) analyses, and circulating diallel studies were strategically integrated to develop new cultivars. Molecular markers were used to assess the GD of 76 candidate parents and verify the crossing of potential F1 hybrids. Based on the complementary agronomic traits and genetic distance, eight elite parents were selected for circulating diallel analysis. The parents and 12 hybrids were evaluated based on 10 morpho-agronomic traits. For each trait, the effects of general and specific combining abilities, as well as the averages of the parents, hybrids, and predicted hybrids, were estimated. Crosses that maximize the genetic gains for the main agronomic traits of C. arabica were identified. Joint analysis of phenotypic and molecular data was used to estimate the correlation between molecular GD, phenotypic diversity (PD), phenotypic mean, and combining ability. The selection of parents that optimize the allele combination for the important traits of C. arabica is discussed in detail.

Breeding programs of the species Coffea canephora rely heavily on the significant genetic variability between and within its two varietal groups (conilon and robusta). The use of hybrid families and individuals has been less common. The objectives of this study were to evaluate parents and families from the populations of conilon, robusta, and its hybrids and to define the best breeding and selection strategies for productivity and disease resistance traits. As such, 71 conilon clones, 56 robusta clones, and 20 hybrid families were evaluated over several years for the following traits: vegetative vigor, incidence of rust and cercosporiosis, fruit ripening time, fruit size, plant height, canopy diameter, and yield per plant. Components of variance and genetic parameters were estimated via residual maximum likelihood (REML) and genotypic values were predicted via best linear unbiased prediction (BLUP). Genetic variability among parents (clones) and hybrid families was detected for most of the evaluated traits. The Mulamba-Rank index suggests potential gains up to 17% for the genotypic aggregate of traits in the hybrid population. An intrapopulation recurrent selection within the hybrid population would be the best breeding strategy because the genetic variability, narrow and broad senses heritabilities and selective accuracies for important traits were maximized in the crossed population. Besides, such strategy is simple, low cost and quicker than the concurrent reciprocal recurrent selection in the two parental populations, and this maximizes the genetic gain for unit of time.

Foi avaliado o progresso da doença e a resistência de cultivares de cevada à Bipolaris sorokiniana. O ensaio foi realizado no campo experimental da Embrapa Trigo em Coxilha, RS. Comparou-se, na taxa de progresso da doença, resistência e severidade de ponta-preta nos grãos, baseando-se estas na escalas de Fetch & Steffeson (1999) e Anderson & Banttari (1976), respectivamente. As cultivares BR 2, MN 698, Embrapa 128, Embrapa 129 e CI 9539 diferiram quanto à taxa de progresso da doença, graus de doença e severidade de ponta--preta nos grãos. As cultivares BR 2, Embrapa 128, Embrapa 129 e MN 698 apresentaram as maiores taxas de progresso da doença, variando de 2,92 a 3,62 quando comparadas com o acesso CI 9539, mas não diferiram entre si pelo teste de Tukey a 5% de probabilidade. O acesso CI 9539 apresentou a menor taxa de progresso da doença (1,17).

ABSTRACT: The biotrophic fungus Hemileia vastatrix causes coffee leaf rust (CLR), one of the most devastating diseases in Coffea arabica . Coffee, like other plants, has developed effective mechanisms to recognize and respond to infections caused by pathogens. Plant resistance gene analogs (RGAs) have been identified in certain plants as candidates for resistance ( R ) genes or membrane receptors that activate the R genes. The RGAs identified in different plants possess conserved domains that play specific roles in the fight against pathogens. Despite the importance of RGAs, in coffee plants these genes and other molecular mechanisms of disease resistance are still unknown. This study aimed to sequence and characterize candidate genes from coffee plants with the potential for involvement in resistance to H. vastatrix . Sequencing was performed based on a library of bacterial artificial chromosomes (BAC) of the coffee clone ‘Híbrido de Timor’ (HdT) CIFC 832/2 and screened using a functional marker. Two RGAs, HdT_LRR_RLK1 and HdT_LRR_RLK2, containing the motif of leucine-rich repeat-like kinase (LRR-RLK) were identified. Based on the presence or absence of the HdT_LRR_RLK2 RGA in a number of differential coffee clones containing different combinations of the rust resistance gene, these RGAs did not correspond to any resistance gene already characterized (SH1-9). These genes were also analyzed using qPCR and demonstrated a major expression peak at 24 h after inoculation in both the compatible and incompatible interactions between coffee and H. vastatrix . These results are valuable information for breeding programs aimed at developing CLR-resistant cultivars, in addition to enabling a better understanding of the interactions between coffee and H. vastatrix .

ABSTRACT Genomic selection (GS) emphasizes the simultaneous prediction of the genetic effects of thousands of scattered markers over the genome. Several statistical methodologies have been used in GS for the prediction of genetic merit. In general, such methodologies require certain assumptions about the data, such as the normality of the distribution of phenotypic values. To circumvent the non-normality of phenotypic values, the literature suggests the use of Bayesian Generalized Linear Regression (GBLASSO). Another alternative is the models based on machine learning, represented by methodologies such as Artificial Neural Networks (ANN), Decision Trees (DT) and related possible refinements such as Bagging, Random Forest and Boosting. This study aimed to use DT and its refinements for predicting resistance to orange rust in Arabica coffee. Additionally, DT and its refinements were used to identify the importance of markers related to the characteristic of interest. The results were compared with those from GBLASSO and ANN. Data on coffee rust resistance of 245 Arabica coffee plants genotyped for 137 markers were used. The DT refinements presented equal or inferior values of Apparent Error Rate compared to those obtained by DT, GBLASSO, and ANN. Moreover, DT refinements were able to identify important markers for the characteristic of interest. Out of 14 of the most important markers analyzed in each methodology, 9.3 markers on average were in regions of quantitative trait loci (QTLs) related to resistance to disease listed in the literature.

Physiology-based differentiation of SH genes and Hemileia vastatrix races is the principal method employed for the characterization of coffee leaf rust resistance. Based on the gene-for-gene theory, nine major rust resistance genes (SH1-9) have been proposed. However, these genes have not been characterized at the molecular level. Consequently, the lack of molecular data regarding rust resistance genes or candidates is a major bottleneck in coffee breeding. To address this issue, we screened a BAC library with resistance gene analogs (RGAs), identified RGAs, characterized and explored for any SH related candidate genes. Herein, we report the identification and characterization of a gene (gene 11), which shares conserved sequences with other SH genes and displays a characteristic polymorphic allele conferring different resistance phenotypes. Furthermore, comparative analysis of the two RGAs belonging to CC-NBS-LRR revealed more intense diversifying selection in tomato and grape genomes than in coffee. For the first time, the present study has unveiled novel insights into the molecular nature of the SH genes, thereby opening new avenues for coffee rust resistance molecular breeding. The characterized candidate RGA is of particular importance for further biological function analysis in coffee.

Coffee leaf rust is caused by Hemileia vastatrix Berk. and Broome and is the most important coffee disease in all regions where coffee is cultivated. Here, we sought to sequence the transcriptome of H. vastatrix race XXXIII to obtain a database for use as a reference in studies of the interaction between the fungus and coffee. In addition, we aimed to identify differentially expressed genes that have the potential to act as effector proteins during the interaction. Sequencing of cDNA libraries from uredospores and from compatible and incompatible interactions at different key time points generated about 162 million trimmed reads. We identified 3523 differentially expressed genes. The results suggested that the fungal transcriptome is dynamically altered over the course of infection and that the interaction with a susceptible plant upregulates a larger set of fungal genes than the interaction with a resistant plant. Co-expression network analysis allowed us to identify candidate genes with the same expression pattern as that of other effectors of H. vastatrix. Quantitative PCR analysis identified seven transcripts that may be effectors involved in the coffee–H. vastatrix interaction. This information provides a basis for obtaining new insights into the molecular mechanisms of infection in this pathosystem. Understanding gene expression during the infection process may contribute to elucidating the molecular mechanisms leading to the breakdown of resistance by new physiological races of the fungus.

Ferrugem da folha do trigo causada pelo fungo Puccinia triticina é, dentre as doenças do trigo, a de maior importância histórica e econômica a nível mundial. É a mais distribuída geograficamente entre as ferrugens dessa cultura. Entretanto, no Brasil não existem estudos epidemiológicos dessa doença. Para os quais são necessários métodos padronizados de quantificação de severidade no campo. Assim, o objetivo deste trabalho foi elaborar uma escala diagramática para padronizar as estimativas de severidade, em avaliações da ferrugem da folha do trigo. A escala foi confeccionada a partir de folhas sintomáticas coletadas aleatoriamente, em área naturalmente infestada, na Universidade Federal de Viçosa, Viçosa-MG. Após a coleta as folhas foram digitalizadas, e com o auxílio do programa Quant determinou-se a área lesionada para a confecção da escala diagramática. Assim a escala proposta apresenta 10 níveis de severidade: 0,1; 1; 2; 4; 8; 16; 32; 64; 80 e 95. A validação da escala foi realizada por 8 avaliadores sem experiência em avaliação de doenças. Os avaliadores inicialmente estimaram a severidade da doença sem o uso da escala, logo em seguida os mesmos avaliadores utilizaram a escala proposta. A acurácia e precisão da escala foram avaliadas por meio de análises de regressão linear. A escala diagramática proposta tornou-se rápida, fácil, de forma acurada, precisa e reproduzível. Esta escala é recomendada como uma ferramenta de auxílio na estimativa da severidade da ferrugem da folha do trigo. Palavras-chave: Puccinia triticcina, severidade, quantificação de doença

The use of resistant cultivars is the most effective strategy for controlling coffee leaf rust caused by the fungus Hemileia vastatrix. To assist the development of such cultivars, amplified fragment-length polymorphism (AFLP) markers linked to two loci of coffee resistance to races I and II as well as pathotype 001 of H. vastatrix were converted to sequence-characterized amplified region (SCAR) and cleaved amplified polymorphic site (CAPS) markers. In total, 2 SCAR markers and 1 CAPS marker were validated in resistant and susceptible parents as well as in 247 individuals from the F2 population. The efficiency of these markers for marker-assisted selection (MAS) was evaluated in F2:3 and backcross (BCrs2) populations genotyped with the developed markers and phenotyped with race II of H. vastatrix. The markers showed 90% efficiency in MAS. Therefore, the developed markers, together with molecular markers associated with other rust resistance genes, were used for F3:4 and BCrs3 coffee selection. The selected plants were analyzed using two markers associated with coffee berry disease (CBD) resistance, aiming for preventive breeding. MAS of F3:4 and BCrs3 individuals with all resistance loci was feasible. Our phenotypic and genotypic approaches are useful for the development of coffee genotypes with multiple genes conferring resistance to coffee leaf rust and CBD.

Three experiments were carried out in an experimental field from Viçosa city, Minas Gerais, Brazil, to compare late blight (LB) (Phytophthora infestans) and early blight (EB) (Alternaria grandis) epidemics under different environmental conditions and fungicide application programs. Each experiment consisted of two side-by-side trials that were arranged in a randomized complete block design with five treatments and five replications. At 30 days after planting the potato (‘Ágata’ cultivar) plants in plots of trials 1 and 2 were inoculated with an isolate of P. infestans (A2 mating type) and four isolates of A. grandis, respectively. Fungicide applications were initiated at seven days after inoculation and repeated at 7- or 15-day intervals. The severity of LB and EB was assessed every two days, and the area under disease progress curve (AUDPC) was calculated for both diseases. The yield was quantified by weighing the tubers of all the plants from each plot after their maturation. Yield data were converted into kg ha-1 and the percentage of loss was calculated for each treatment. Based on the AUDPC, the LB severity was greater than the EB severity under all three environmental conditions, and this was reflected in the yield. LB and EB caused yield losses as high as of 82 and 45%, respectively. The fungicide effects on both LB and EB and the associated yield losses changed according to the environmental conditions, therefore, indicating the importance of using tools such as a forecast system to help farmers to decide the best time for fungicide application.

Coffee leaf rust caused by the fungus Hemileia vastatrix is one of the most important leaf diseases of coffee plantations worldwide. Current knowledge of the H. vastatrix genome is limited and only a small fraction of the total fungal secretome has been identified. In order to obtain a more comprehensive understanding of its secretome, we aimed to sequence and assemble the entire H. vastatrix genome using two next-generation sequencing platforms and a hybrid assembly strategy. This resulted in a 547 Mb genome of H. vastatrix race XXXIII (Hv33), with 13,364 predicted genes that encode 13,034 putative proteins with transcriptomic support. Based on this proteome, 615 proteins contain putative secretion peptides, and lack transmembrane domains. From this putative secretome, 111 proteins were identified as candidate effectors (EHv33) unique to H. vastatrix, and a subset consisting of 17 EHv33 genes was selected for a temporal gene expression analysis during infection. Five genes were significantly induced early during an incompatible interaction, indicating their potential role as pre-haustorial effectors possibly recognized by the resistant coffee genotype. Another nine genes were significantly induced after haustorium formation in the compatible interaction. Overall, we suggest that this fungus is able to selectively mount its survival strategy with effectors that depend on the host genotype involved in the infection process.

Genomic Selection (GS) has allowed the maximization of genetic gains per unit time in several annual and perennial plant species. However, no GS studies have addressed Coffea arabica, the most economically important species of the genus Coffea. Therefore, this study aimed (i) to evaluate the applicability and accuracy of GS in the prediction of the genomic estimated breeding value (GEBV); (ii) to estimate the genetic parameters; and (iii) to evaluate the time reduction of the selection cycle by GS in Arabica coffee breeding. A total of 195 Arabica coffee individuals, belonging to 13 families in generation of F2, susceptible backcross and resistant backcross, were phenotyped for 18 agronomic traits, and genotyped with 21,211 SNP molecular markers. Phenotypic data, measured in 2014, 2015, and 2016, were analyzed by mixed models. GS analyses were performed by the G-BLUP method, using the RKHS (Reproducing Kernel Hilbert Spaces) procedure, with a Bayesian algorithm. Heritabilities and selective accuracies were estimated, revealing moderate to high magnitude for most of the traits evaluated. Results of GS analyses showed the possibility of reducing the cycle time by 50%, maximizing selection gains per unit time. The effect of marker density on GS analyses was evaluated. Genomic selection proved to be promising for C. arabica breeding. The agronomic traits presented high complexity for they are controlled by several QTL and showed low genomic heritabilities, evidencing the need to incorporate genomic selection methodologies to the breeding programs of this species.

Resumo: O objetivo deste trabalho foi avaliar a eficiência da aplicação foliar de fungicidas na redução da incidência de patógenos fúngicos, de grãos ardidos e de fumonisinas totais em grãos de milho (Zea mays). Foram conduzidos três ensaios: um no município de Luís Eduardo Magalhães, na Bahia, e dois em Sete Lagoas, em Minas Gerais, nas safras 2010/2011 e 2011/2012, com cultivo de diferentes híbridos comerciais. Os seguintes fungicidas foram aplicados zero, uma e duas vezes: picoxistrobina + ciproconazol, piraclostrobina + epoxiconazole, trifloxistrobina + tebuconazole, azoxistrobina + ciproconazol e tiofanato metílico. Em todos os ensaios, foram realizados a quantificação da incidência de grãos ardidos, o teste de patologia de sementes e a quantificação dos teores de fumonisinas totais. Não foi observada diferença significativa para os fatores fungicida e número de aplicações, exceto para rendimento de grãos, em todos os ensaios. Esses resultados são indicativos da ineficiência da aplicação de fungicidas na redução da incidência de patógenos fúngicos, de grãos ardidos e dos teores de fumonisinas totais em grãos de milho.

Objetivou-se propor e validar uma escala diagramática para quantificar a antracnose do colmo em milho. A severidade da antracnose foi estimada por dez avaliadores sem o uso de escala em 139 entrenós, e os mesmos avaliadores avaliaram os entrenós usando uma escala publicada anteriormente na literatura (primeira escala) e uma nova escala proposta. Com o uso da escala proposta, todas as variáveis foram significativamente diferentes em relação à primeira escala, e os valores foram mais próximos de uma medição acurada (r=0,97, Cb=0.98, u=0.09, υ=1.06, ρc=0.96). Os maiores desvios do erro foram observados quando os avaliadores atribuíram notas sem o uso de escalas e com a primeira escala, com vários exemplos de erros maiores do que 30% do valor real. Com a escala proposta, poucos erros acima de 15% do valor real foram encontrados, e a maioria das notas dos avaliadores não ultrapassou, para mais ou para menos, 10% do valor real. Uma maior confiabilidade na estimativa da severidade da doença foi obtida com o uso da escala proposta, com a qual 100% das comparações resultaram em um R2>0,90. A nova escala diagramática proposta no presente trabalho melhorou a acurácia, precisão e confiabilidade das estimativas da severidade da antracnose do colmo em milho

Botrytis blight or gray mold is a highly destructive disease caused by Botrytis spp., that infects flowers, trees vegetables, fruit, especially grapevines and strawberry. Three new compounds with general formula (A)2[Zn(4-FC6H4SO2N=CS2)2], where A = PPh3CH3 (2a), PPh3C2H5 (2b), PPh3C4H9 (2c), and the previously published compounds where A = PPh4 (2d) and NBu4 (2e), were synthesized by the reaction of 4-fluorophenylsulfonyldithiocarbimate potassium dihydrate and zinc(II) acetate dihydrate with the appropriate counter cations (A) halides. The new compounds were characterized by infrared, 1H and 13C NMR spectroscopies. All these salts inhibited the growth of Botrytis cinerea, with compounds 2c and 2d showing greater antifungal activity than zinc dimethyldithiocarbamate, the active principle of the fungicide Ziram. The bis(dithiocarbimate)zincate(II) salts are also active against the bacteria Escherichia coli and Staphylococcus aureus.

This work aimed to characterize accessions that represent the C. canephora germplasm conserved and cultivated in Brazil. A total of 130 accessions from germplasm banks of IAC (São Paulo), UFV (Minas Gerais) and also collected in plantations of the State of Espírito Santo and Rondônia were evaluated with a set of 20 new microsatellite primers. Multivariate methods were used to estimate the relationship among the accessions. High level of polymorphism and two major diversity clusters were identified. First cluster was composed by the accessions conserved in the IAC and UFV collections and the second was formed by accessions collected in areas under cultivation. Accessions from Espírito Santo and Rondônia were clear separated, composing two subclusters. Despite the great polymorphism found in Brazilian plantations, the diversity may be increased, because a new threshold in the genetic gains is expected on breeding programs with the intensification of the use of conserved germplasm.

This present work aimed to assess the effect of different concentrations of cassava starch, associated or not with prochloraz fungicide, on the postharvest conservation of 'Pedro Sato' guavas. Physiologically mature fruits were immersed in a solution of prochloraz (49.5 g/100 liters of water) for 5 min. Fruit treated with distilled water and air dried were used as control. They were immersed in cassava starch suspension at concentrations of 0, 20, 30 and 40 g/L, plus 0.5 mL/L of mineral oil. The fruits were stored at 21.0 ± 1.0 ºC and relative humidity of 85 ± 5%, for 12 days, and were examined at every three days. The combination of prochloraz and cassava starch resulted in delayed loss of firmness and yellowness and inhibited the incidence of lesions caused by Colletotrichum gloeosporioides during the 12 days of storage. Fruits treated with 40 g/L of starch, whether containing prochloraz or not, had unpleasant taste and odor, which suggests the occurrence of fermentation. Control fruits, with and without prochloraz, and those treated with starch with no prochloraz, had nearly 100% lesion occurrence within the 12 days. Starch suspension of 30 g/L, containing prochloraz, was the most effective in maintaining fruit quality.

O objetivo deste trabalho foi avaliar a eficiência do uso de multilinhas dinâmicas, por meio de misturas genéticas em populações de híbridos triplos, no manejo da antracnose do sorgo, causada pelo fungo Colletotrichum sublineolum. Foram obtidos 18 híbridos triplos a partir de sete linhagens que continham genes distintos para resistência à doença. Os 25 genótipos de híbridos e linhagens foram avaliados em campo. Verificou-se, em alguns híbridos, grau de resistência superior ao observado para a linhagem mais resistente utilizada nos cruzamentos, o que indica efeito aditivo dos genes de resistência das diferentes linhagens na composição da resistência final dos híbridos. O usodas multilinhas dinâmicas reduziu a intensidade da doença no campo e aumentou a produtividade. Essa estratégia torna possível a utilização de linhagens que apresentam características agronômicas desejáveis, mas são suscetíveis à antracnose.

Here we describe the total syntheses and characterization by elemental analyses, infrared and NMR spectroscopy of three new compounds analogous to avenaciolide, a bis-γ-lactone isolated from Aspergillus avenaceus that possesses antifungal activity, where the octyl group of the natural product was replaced by aromatic groups containing chlorine and fluorine atoms. The effects of the avenaciolide, the novel compounds and their synthetic precursors on mycelia development and conidia germination of Colletotrichum gloeosporioides and Fusarium solani were evaluated in vitro. The title compounds were almost as active as avenaciolide. The absolute structures of the chlorinated analogs were determined by X-ray diffraction analysis.

O objetivo deste trabalho foi identificar marcadores moleculares relacionados à resistência do cafeeiro (Coffea arabica) à ferrugem (Hemileia vastatrix). Foram identificadas sequências de DNA potencialmente envolvidas na resistência do cafeeiro a doenças, por meio de análise "in silico", a partir das informações geradas pelo Projeto Brasileiro do Genoma Café. A partir das sequências mineradas, foram desenhados 59 pares de iniciadores para amplificá-las. Os 59 iniciadores foram testados em 12 cafeeiros resistentes e 12 susceptíveis a H. vastatrix. Vinte e sete iniciadores resultaram em bandas únicas e bem definidas, enquanto um deles amplificou fragmento de DNA em todos os cafeeiros resistentes, mas não nos suscetíveis. Esse marcador molecular polimórfico amplificou uma região do DNA que corresponde a uma janela aberta de leitura parcial do genoma de C. arabica que codifica uma proteína de resistência a doenças. O marcador CARF 005 é capaz de diferenciar os cafeeiros analisados em resistentes e susceptíveis a H. vastatrix.

Spot bloth caused by Bipolaris sorokiniana is an important wheat desease mainly in hot and humid regions. The aim of this study was to evaluate the response of wheat to different sources and modes of Si application, as related to the severity of wheat spot blotch and plant growth, in two Si-deficient Latosols (Oxisols). An greenhouse experiment was arranged in a 2 x 5 factorial completely randomized design, with eight replications. The treatments consisted of two soils (Yellow Latosol and Red Latosol) and five Si supply modes (no Si application; Si applied as calcium silicate and monosilicic acid to the soil; and Si applied as potassium silicate or monosilicic acid to wheat leaves). No significant differences were observed between the two soils. When Si was applied to the soil, regardless the Si source, the disease incubation period, the shoot dry matter yield and the Si content in leaves were greater. Additionally, the final spot blotch severity was lower and the area under the spot blotch disease progress curve and the leaf insertion angle in the plant were smaller. Results of Si foliar application were similar to those observed in the control plants.A mancha-marrom, causada por Bipolaris sorokiniana em plantas de trigo é de grande importância em regiões quentes e úmidas. O objetivo deste trabalho foi avaliar a resposta do trigo a diferentes fontes e modos de aplicação de silício na severidade da mancha-marrom e no crescimento das plantas em dois Latossolos com níveis deficientes de Si. O experimento foi conduzido em casa de vegetação, e os tratamentos, dispostos em esquema fatorial 2 x 5 [dois tipos de solo (Latossolo Amarelo e Latossolo Vermelho) e cinco modos de fornecimento de Si (sem aplicação; aplicação no solo, tendo o silicato de cálcio ou o ácido monossilícico como fontes; e o Si aplicado via foliar, usando o silicato de potássio ou o ácido monossilícico como fontes)] com oito repetições, em delineamento inteiramente casualizado. Não houve efeito do tipo de solo em nenhuma característica avaliada. Quando o Si foi aplicado no solo, independentemente da fonte, o período de incubação da doença, a produção de matéria seca da parte aérea e o teor de Si nas folhas foram maiores. Adicionalmente, a severidade final da mancha-marrom foi menor e a área sob a curva do progresso da doença assim como o ângulo de inserção foliar foram menores. A aplicação do Si via foliar não foi eficiente, não diferindo da testemunha.

Thirty-three coffee SSR primers from enriched genomic library with (GT)15 and (AGG)10 repeats were analyzedin 24 coffee tree accessions. Twenty-two primers were polymorphic among accessions; the number of alleles ranged from 2 to13, with the mean number of 5.1 alleles per primer. PIC values ranged from 0.08 to 0.79. The highest mean PIC values werefound for C. canephora (0.46), and the lowest values for C. arabica (0.22) and triploids (0.22) accessions. The polymorphicSSR markers used in this study were useful for genetic fingerprinting in the coffee tree, especially in the C. canephora and theleaf rust resistant arabica cultivars.

A produção da soja pode ser afetada pela ocorrência de várias doenças. Dentre estas, a ferrugem, causada pelo fungo Phakopsora pachyrhizi, tem se destacado. Atualmente, novas estratégias de controle para essa doença devem ser pesquisadas. Assim, este trabalho teve como objetivo avaliar a eficiência do silicato de potássio (KSi), acibenzolar-S-metil e fungicidas no controle da ferrugem da soja. Um experimento foi conduzido em condições de campo, em delineamento em blocos ao acaso, utilizando-se 10 tratamentos, com três repetições. Foi utilizada a cultivar 'Monarca' por ser suscetível à ferrugem. Os tratamentos utilizados foram: T1 - testemunha (pulverização com água); T2 - KSi (1,2kg ha-1); T3 - KSi (2,4kg ha-1); T4 - KSi (3,6kg ha-1); T5 - KSi (4,8kg ha-1); T6 - tebuconazole (125g de i.a. ha-1); T7 - cloreto de potássio (61,72g L-1); T8 - mancozebe (2400g de i.a. ha-1); T9 - mancozebe (2400g de i.a. ha-1) + KSi (1,2kg ha-1) e T10 - acibenzolar-S-metil (125g de i.a. ha-1). As plantas da bordadura foram inoculadas com uma suspensão de 5x10(5) uredosporos mL-1 no estádio V4 para constituírem fonte de inóculo, para as parcelas centrais. As plantas foram pulverizadas com os produtos que constituíram os tratamentos T2, T3, T4, T5, T7, T8 e T9 nos estádios V5, R1, R4 e R5.4 e os tratamentos T6 e T10 nos estádios R1, R4 e R5.4. As plantas foram pulverizadas com atomizador costal manual de bico cônico empregando-se um volume de calda de 200L ha-1. Foram realizadas cinco avaliações da severidade da ferrugem nos terços inferior, médio e superior das plantas utilizando-se uma escala diagramática variando de 0,6 a 78,5%, e os dados obtidos foram utilizados para calcular a área abaixo da curva do progresso da ferrugem (AACPF). Não houve efeito significativo das doses de KSi na AACPF e severidade máxima (Ymax) nos terços inferior, médio e superior das plantas, além da produtividade. Os tratamentos 8, 9 e 10 apresentaram eficiência intermediária no controle da ferrugem. O tratamento 6 foi o mais eficiente no controle da doença por resultar nos menores valores da AACPF e Ymax para os terços inferior, médio e superior, além de uma produtividade significativamente maior em relação aos demais tratamentos.Soybean production can be affected by the occurrence of several diseases. Among them, the rust, caused by the fungus Phakopsora pachyrhizi, has been outstanding. Nowadays, new strategies to control soybean rust need to be searched. Therefore, this study aimed to evaluate the efficiency of potassium silicate (KSi), acibenzolar-S-methyl and some fungicides on the control of soybean rust. An experiment was carried out under field conditions in a randomized complete block design with 10 treatments and three replications. The cultivar 'Monarca' was used because it is susceptible to rust. The treatments used were: T1 - control (plants sprayed with water); T2 - KSi (1.2kg ha-1); T3 - KSi (2.4kg ha-1); T4 - KSi (3.6kg ha-1); T5 - KSi (4.8kg ha-1); T6 - tebuconazol (125g de a.i. ha-1); T7 - potassium cloride (61.72g L-1); T8 - mancozeb (2400g de a.i. ha-1); T9 - mancozeb (2400g de a.i. ha-1) + KSi (1.2kg ha-1) and T10 - acibenzolar-S-methyl (125g de a.i. ha-1). Plants from the two lateral lines were inoculated with a suspension of 5x10(5) uredospores/mL at the V4 growth stage to produce inoculum to infect plants at the two central lines. Plants were sprayed with the products that constituted the treatments T2, T3, T4, T5, T7, T8, and T9 at V5, R1, R4, and R5.4 growth stages; and the treatments T6 and T10 at R1, R4, and R5.4 growth stages. Plants were sprayed using a costal sprayer in a volume of 200L ha-1. A total of five disease severity evaluations at the low, medium and high part of the plant canopy were done using a diagrammatic scale ranging from 0.6 to 78.5%. Data were used to calculate the area under rust progress curve (AURPC). There was no effect of the KSi rates on AURPC and final disease severity (Ymax) at the low, medium and high part of the plant canopy. Yield was also unaffected. The treatments 8, 9, and 10 had an intermediary efficiency on rust control. The treatment 6 was the most efficient on rust control giving the lowest values for AURPC and Ymax for the low, medium and high part of the plant canopy. High values for yield were also obtained using this treatment as compared to the others.

O objetivo deste trabalho foi caracterizar a herança da resistência do Híbrido de Timor UFV 443-03 à ferrugem-do-cafeeiro (Hemileia vastatrix). Para isso, a raça II e o patótipo 001 de ferrugem foram inoculados em 246 plantas da população F2, 115 plantas do retrocruzamento suscetível (RC S) e 87 plantas do retrocruzamento resistente (RC R), originadas do cruzamento entre o genótipo suscetível cv. Catuaí Amarelo IAC 64 e a fonte de resistência Híbrido de Timor UFV 443-03. Para ambos os inóculos, a cv. Catuaí Amarelo IAC 64 foi suscetível, enquanto o Híbrido de Timor UFV 443-03, a planta representante da geração F1 e as plantas do RC R foram resistentes. As plantas F2, quando inoculadas com a raça II, apresentaram dois padrões de segregação significativos: 15:1 e 61:3. A herança da resistência foi confirmada pela inoculação das plantas do RC S, que segregaram na proporção de 3:1, padrão esperado para herança condicionada por dois genes. A hipótese de segregação 7:1 para três genes foi rejeitada. Resultados semelhantes foram obtidos para o patótipo 001. Dois genes dominantes e independentes conferem a resistência genética do Híbrido de Timor UFV 443-03 à raça II e ao patótipo 001 de H. vastatrix.The aim of this work was to characterize the resistance inheritance of the Timor Hybrid UFV 443-03 to coffee leaf rust (Hemileia vastatrix). For this, the race II and pathotype 001 of coffee leaf rust were inoculated in 246 F2 plants, 115 susceptible backcrossing (BCS) plants, and 87 resistant backcrossing (BC R) plants, derived from the crossing between the susceptible genotype 'Catuaí Amarelo' IAC 64 and the resistance source Timor Hybrid UFV 443-03. For both inoculums, the 'Catuaí Amarelo' IAC 64 was susceptible, while the Timor Hybrid, the plant representing F1 generation, and the BC R plants were resistant. The F2 plants inoculated with race II presented two significant segregation ratios: 15:1 and 61:3. The resistance inheritance was verified by the inoculation of the BCS plants, which segregated at a 3:1 ratio, an expected pattern for the inheritance controlled by two genes, whereas the segregation hypothesis of 7:1 for three genes was rejected. Two independent and dominant genes confer the genetic resistance of Timor Hybrid UFV 443-03 to race II and pathotype 001 of H. vastatrix.

With the objective of developing new SSR markers for Coffea arabica, two enriched genomic libraries withprobes (GT)15 and (AGG)10 were constructed. A total of 835 clones were sequenced and 756 presented good quality sequences.Redundant sequences were observed for 113 clones (14.94%). SSRs were found in 287 clones (38%). An estimated size of417.5Kb of the C. arabica genome was sampled, with an average of one SSR per 1.46Kb. Dinucleotide repeats were morefrequent than trinucleotides. Four repeat sequences, (AG/CT)n, (AC/GT)n, (AAG/CTT)n, and (AGG/CCT)n represented 61.1%of the total observed. A total of 96 SSR primers were designed and tested by PCR for two C. arabica genotypes. Ninety new SSRmarkers were validated for further genetic studies of C. arabica.

O estudo da eficiência nutricional de plantas enxertadas de cafeeiro é importante para a seleção de combinações enxerto/porta-enxerto visando desenvolvimento e produção máximos. O presente trabalho teve como objetivo avaliar as diferenças genéticas na eficiência de absorção, no transporte e na utilização de Potássio, Cálcio e Magnésio em mudas enxertadas de cafeeiro. O plantio foi realizado em vasos de 20L contendo como substrato terra, areia e esterco na proporção de 3:1:1, em que as plantas permaneceram por 18 meses até a coleta do experimento. Utilizaram-se como enxertos quatro genótipos de Coffea. arabica L.: as variedades Catuaí Vermelho IAC 15 e Oeiras MG 6851 e os híbridos H419-10-3-4-4 e H514-5-5-3 do programa de melhoramento da EPAMIG/UFV. Como porta-enxerto, foram empregados cinco progênies famílias de meios-irmãos de clones de Coffea canephora Pierre cv. Conilon: "ES 21", "ES 36", "ES 26", "ES 23" e "ES 38" do programa de melhoramento de café robusta do INCAPER. Houve variação da eficiência nutricional de K, Ca e Mg das plantas de cafeeiro em função da combinação enxerto/porta-enxerto. Na maioria das vezes, as plantas enxertadas tiveram desempenho inferior ao do pé-franco quanto à eficiência de absorção, translocação e utilização do K, Ca e Mg, bem como na produção de matéria seca. As combinações da variedade Catuaí Vermelho IAC 15 com os porta-enxertos ES 26 e ES 23 foram eficientes quanto à utilização de Mg e à produção de matéria seca. A baixa eficiência de absorção de K e Mg das combinações de enxertia com a cultivar Oeiras MG 6851 podem ter contribuído para a redução de produção de matéria seca total das mesmas.Studies on the nutritional efficiency of grafted coffee trees are important for the selection of the rootstocks/grafts combinations that aim at for a good development and maximum yield. This study aimed to evaluate the genetic differences in the efficiency of K, Ca and Mg uptake, transport and use in grafted coffee seedlings. Trees were planted in 20-L pots containing soil, sand and manure (3:1:1) to grow for 18 months, until harvest. As grafts, four genotypes of Coffea arabica L were used: varieties Catuaí Vermelho IAC 15 and Oeiras MG 6851 and hybrids H419-10-3-4-4 and H514-5-5-3, of the breeding program of EPAMIG/UFV. As rootstocks, five half-sib progenies of Coffea canephora Pierre cv. Conilon clones were used: 'ES 21', 'ES 36', 'ES 26', 'ES 23' and 'ES 38', of the robust coffee breeding program of INCAPER. The nutritional efficiency of the coffee trees regarding K, Ca and Mg varied with the graft/ rootstock combination. The performance of the grafted coffee plants was inferior to the control varieties, with regard to the nutritional efficiency and dry matter yield. Catuaí Vermelho IAC 15 combined with the rootstocks ES 26 and ES 23 was highly effective regarding Mg utilization and dry matter yield. The dry weight reduction in the cv. Oeiras MG 6851 combinations may be explained by the low potassium and magnesium uptake efficiency.

Três experimentos foram montados entre os anos de 2000 e 2002, em condições de campo, de Viçosa, estado de Minas Gerais, com a finalidade de avaliar o efeito de epidemias de pinta-preta (Alternaria solani) na produção de batata (Solanum tuberosum) e determinar o inicio de sintomas da pinta preta na cultura de batata. Usando o método de gradiente de severidade da doença, foram obtidas em cada experimento quatro epidemias da doença, com diferentes severidades, desde D1 até D4, em ordem decrescente, o que permitiu comparar o efeito das epidemias no crescimento da planta e na produção de tubérculos, bem como determinar o momento de se iniciar o controle da doença. Tendo como base o tempo desde o plantio até o aparecimento dos primeiros sintomas da epidemia, foram avaliados os seguintes métodos para previsão da doença: dias acumulados (DA); graus-dia acumulados (GD), tendo como temperatura-base 7ºC; e dias fisiológicos acumulados (DF), tendo como temperatura mínima 7ºC, máxima de 30ºC e ótima de 21ºC. O estabelecimento do gradiente da doença mostrou diferenças significativas na produção em cada experimento. As maiores reduções na produção dos tubérculos ocorreram na parcela não tratada com fungicida D1, com 49,6% em 2000; 52,7% em 2001; e 58,2% em 2002. A previsão da epidemia utilizando-se os métodos DA e GD não indicou o momento certo para iniciar o controle da epidemia. O método DF foi o mais adequado, estabelecendo-se o primeiro sintoma entre 240 e 333 DF. Conclui-se que a pinta-preta, dependendo da severidade, afeta a área foliar e a produção de tubérculos. Dos métodos para determinar o estabelecimento da pinta-preta, o DF apresentou o maior potencial, recomendando-se seu uso para iniciar o manejo da doença aos 250 DF após o plantio, sempre e quando as condições ambientais favorecem o estabelecimento do patógeno.The influence of an early blight epidemic on potato tuber yield was evaluated in three field experiments during 2000 to 2002 crop seasons under Viçosa, Minas Gerais state growing conditions. Through a disease severity gradient method, used four different dosages of fungicide chloratalonil were obtained four epidemic levels with severity range of D1 (maximum), plot without fungicide treatment, to D4 (minimum), plot with fully dosage fungicide commercial recommended, were obtained, which allowed for comparison of the epidemic effect on plant growth and tuber yield, and indicated the time for initiating of the first early blight (Alternaria solani) lesions on potato foliage The disease was predicted by using the methods based either degree days (DD) with base temperature of 7ºC and physiological days (PD) having minimum, optimum and maximum temperature of 7, 21 and 30ºC, respectively, accumulated during the period between planting and the first symptom appearance. Plots with higher disease levels along the gradient had significantly loss tuber yield in all trials. The highest yield reduction of 49,6; 52,7 and 58,2% occurred in D1, plots without fungicide treatment, during the years 2000, 2001 and 2002, respectively. The epidemic prediction through accumulated DD or PD did not indicate the appropriate time to initiate the epidemic control. However, the PD method that predicted the first symptoms between 240 and 333 accumulated PDs was found to be more adequate. The data revealed that green leaf area and tuber yield reduction caused by the early blight is dependent upon the disease severity. Compared to the others, the PD method appears to be most suitable to determine when the disease will establish, and thus can be recommended to initiate the disease management at 250 accumulated PDs, under disease-favorable climatic conditions.

A partial map of Coffea arabica L. was constructed based on a backcross population and RAPD markers.From a total of 178 markers evaluated, only 134 that segregated 1:1 (P>0.05) were used to develop the map. Seventeenmarkers were not linked, while 117 formed 11 linkage groups, covering a genome distance of 803.2 cM. The maximumdistance between adjacent markers was 26.9 cM, and only seven intervals exceeded 20 cM. The markers were further used forassisted selection of the plants closest to the recurrent parent, to accelerate the introgression of rust resistance genes in thecoffee breeding program. Three BC1 plants resistant to coffee leaf rust and with high genetic similarity to Catuaí wereselected and integrated in the following backcross cycles.

The adsorption of triadimenol (1-(4-chlorophenoxy)-3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)butan-2-ol) on soil samples with varying contents of organic matter was studied. The adsorption was described by means of the Freundlich's isoterm. An increase in the capacity of adsorption was observed as the content of organic carbon in the matrix increased. That effect was observed when removing the organic matter from the soil, when adding a urban waste compost to the soil sample as well as to the soil sample without organic matter, and also after leaving proportions of urban waste compost incubated in these matrices for a period of 120 days. The results show that the adsorption of the triadimenol in the soil is dependent of its content of organic carbon.

Objetivando avaliar a intensidade da mancha-de-olho-pardo do cafeeiro, variedade Catuaí Vermelho, com relação ao estado nutricional das plantas quanto a N e K, realizou-se um experimento no viveiro da Universidade Federal de Viçosa, em Viçosa, MG, utilizando solução nutritiva circulante. Empregaram-se 16 tratamentos, em delineamento inteiramente casualizado, com três repetições e duas plantas por parcela, em esquema fatorial com quatro doses de K (3, 5, 7 e 9mmol/L) e quatro doses de N (3, 7, 11 e 15mmol/L). Após sete inoculações de conídios, e avaliações, colheram-se as plantas. A produção de matéria seca total, a área foliar total, e a área abaixo da curva de progresso (AACP) do número total de folhas não foram influenciadas pelas doses de K, mas aumentaram com o incremento das doses de N. Observou-se elevação, na AACP, do número de lesões por folha, e na desfolha com o aumento das doses de K e a redução das doses de N. A elevação nas doses de K promoveu redução nos teores foliares de Ca e Cu. Osteores foliares de P, Mg, Mn e Fe não foram influenciados pelas doses de K e tiveram pequena redução com o aumento de N na solução, elevando-se a seguir.The experiment was carried out at the coffee nursery of the Universide Federal de Viçosa, in Viçosa, MG, Brazil, using nutrient circulating solution to evaluate the intensity of brown-eye spot (Cercospora coffeicola), variety Catuaí Vermelho, as a function of N and K. Acompletely randomized design with 16 treatments, three replicates, and two plants per plot was used in a factorial with four levels of K (3, 5, 7 and 9mmol/L) combined with four levels of N (3, 7, 11 and 15mmol/L). After seven inoculations and evaluations, the plants were picked. Total dry matter production, total leaf area, and the area below the curve of progress (AACP) for the total number of leaves were not influenced by the levels of K, but increased with increasing levels of N. There was increase in AACP areas for the number of lesions per leaf and defoliation, with the increase of K levels, and a reduction of N levels. The increase in K levels reduced the Ca and Cu leaf contents, indicating possible relation between its contents and the increase of the disease. The P, Mg, Mn, and Fe leaf contents were not influenced by the K levels, and had a small reduction with increased N contents in the nutrient solution, increasing thereafter.

O presente trabalho teve por objetivo avaliar o efeito da calda Viçosa sobre a nutrição e produtividade do feijoeiro, sob condições de campo. Os tratamentos foram assim definidos: (CV) calda Viçosa (2g x l-1 ZnSO4- 7H2O + 6g x l-1 MgSO4-7H2O + 5g x l-1 CuSO4-5H2O + 1g x l-1 H3BO3 + 4g x l-1 KCl + 3,5g x Ca(OH)2); (CV+Mo) calda Viçosa com adição de 0,29g x l-1 molibdato de amônio; (CV-Mg) calda Viçosa com supressão de magnésio; (CV-Zn) calda Viçosa com supressão de zinco; (CV-B) calda Viçosa com supressão de boro; (Mo) 0,29g x l-1 molibdato de amônio puro; (F) tiofanato metílico + chlorotalonil e (T) testemunha. O delineamento utilizado foi em blocos ao acaso com oito tratamentos e quatro repetições. Os tratamentos foram aplicados aos 28 e 35 dias após a emergência das plantas, por meio de pulverizações foliares, à exceção do tratamento (Mo) que foi aplicado apenas aos 28 dias. O volume de calda aplicado foi de 500 l x ha-1. A calda Viçosa, modificada ou não, aumentou a produção acima de 35% em relação a testemunha. Os tratamentos (CV–B), (CV+Mo) e o Mo apresentaram maior produção e se destacaram no número médio de vagens por planta, número médio de sementes por vagem e peso dos grãos. Os tratamentos F e T apresentaram os menores valores de produção e de seus componentes, além de não terem atingido os teores mínimos de boro e cobre, considerados críticos para o feijoeiro. Todos os demais tratamentos apresentaram os teores de B, Cu, Zn e N dentro dos níveis considerados críticos para o feijoeiro. Os tratamentos Mo e (CV+Mo) provocaram aumentos significativos nos teores de nitrogênio nas folhas. Os tratamentos com aumento de produção de no mínimo 55% foram calda Viçosa +Mo, calda Viçosa sem Bo e o molibdato de amônio sozinho. Aumento na produção entre 38% e 48% foi obtido com os tratamentos calda Viçosa, calda Viçosa sem o sulfato de magnésio e a calda Viçosa sem o sulfato de zinco. O tiofanato metílico + chlorothalonil aumentou somente 13% a produção de feijão

Neste trabalho, a calda Viçosa e suas modificações foram avaliadas no controle da mancha-angular e na produtividade do feijoeiro. O teste foi conduzido em casa-de-vegetação, em delineamento inteiramente casualizado, com oito tratamentos e cinco repetições, empregando-se o cultivar “milionário 1732” em recipientes de 1dm3. A adubação de plantio constou de 2,5g por vaso da fórmula 4-14-8. Cada unidade experimental era constituída por 1 vaso com 2 plantas. As atomizações foram realizadas aos 28 e 35 dias após emergência das plantas. As inoculações de Phaeoisariopsis griseola na concentração de 106 conídios por ml foram feitas aos 36 dias após a emergência. Avaliaram-se os seguintes tratamentos: 1- calda Viçosa; 2- calda Viçosa com adição de molibidato de amônio; 3- molibidato de amônio; 4- calda Viçosa sem sulfato de magnésio; 5- calda Viçosa sem sulfato de zinco; 6- calda Viçosa sem ácido-bórico; 7- tiofanato metílico e 8- testemunha (sem pulverização). A avaliação constou de uma escala de severidade de 1- plantas sadias, 9- severidade máxima, e da produção de grãos. A maior produtividade foi obtida no tratamento com calda Viçosa sem ácido bórico. Os tratamentos com calda Viçosa modificada ou não igualaram-se ao tiofanato metílico em relação ao controle da mancha-angular

ABSTRACT: Adoption of resistant cultivars is the primary measure used to control anthracnose stalk rot. The goal of this study was to identify maize-resistant genotypes to anthracnose stalk rot, which are similar to the hybrid 2B710. Experiments were performed at Embrapa Maize and Sorghum experimental fields in Brazil. The first experimental trial evaluated 234 maize lines as well as two commercials hybrids, BRS1010 (susceptible) and 2B710 (resistant). Artificial inoculations were performed with a strain at the blister (R2) phase, and evaluation of disease severity was performed after 30 days. The second experimental trial evaluated 48 maize lines and hybrids, inoculated with two Colletotrichum graminicola strains. In the first trial, eight resistance groups were formed, and the last lines were more resistant, as was the hybrid 2B710, with values between 11.50% and 23.0% of severity. In the second trial, there was an interaction between the two factors, lines and isolates, and the lines often showed the same reaction features as those obtained in the first trial. However, the disease severity was higher for most lines, even when using other isolates. These lines with effective levels of resistance could be used in future studies of inheritance, in programs to develop hybrids, and to identify molecular markers associated with resistance to anthracnose stalk rot in maize.