The aims of this study were: (a) to evaluate the resistance of coffee cultivars to Pseudomonas syringae (PS); (b) verify if there are coffee genotypes that present less wounds on the leaves; (c) to study the correlation between amount of wounds and PS severity. The field trial was installed in April 2014 at the IAPAR’s experimental station (Londrina, Paraná, Brazil). 18 Arabica coffee cultivars were evaluated. The cultivars Mundo Novo IAC 376-4 and Catuaí Vermelho IAC 81 were the susceptible controls and IPR 102 was the resistant control. After 32 months of planting the field trial, resistance to PS was evaluated in December 2016. The evaluation of the PS severity was carried out under conditions of natural infections of P. syringae pv. garcae and P. syringae pv. tabaci based on the symptoms, using a grading scale from 1 to 5. The number of wounds on the leaves of the eight cultivars were counted. The results showed that IPR 102 was resistant to Pseudomonas syringae, whereas IPR 99, Arara, IPR 107, Acauã, Sabiá, Catucaiam 24137, Japy and Catuaí Vermelho IAC 81 were susceptible. Mundo Novo and Catucaí Amarelo 2SL were more susceptible than Catuaí Vermelho. IPR 106, Japiam, Catiguá MG 2, Catiguá MG 1 and IBC Palma 2 showed moderate resistance, while IPR 103 and Catucaiam 2015479 were moderately susceptible. The cultivars IPR 102 and IPR 106 presented resistance to wounding because they had lower wounds than other cultivars. Increased leaf wounds was associated with increased P. syringae severity.

control and early planting are whitefly control methods. Chemical control has not been effective due to difficul-To determine the phytochemical relationship of six sesame (Sesaties of the spray coverage to reach eggs and nymphs mum indicum L.) genotypes and their resistance against whiteflies (Bemisia tabaci Gennadius), a randomized complete block field trial on the abaxial surface of the leaf (Puentes, 1999). In with six treatments (genotypes) and four replications was conducted in addition, low profitability of sesame makes chemical the Microsur growing area of the Municipio Santa Rosalìa, Portuguesa control of minimal or no consideration. State, Venezuela. Whitefly eggs and nymphs were counted weekly Because major population outbreaks of sweetpotato during 6 wk in each experimental plot. At the end of the crop cycle, whitefly occur at the end of February (Pereira and the presence or absence of eight secondary metabolites from each Laurentin, 2001), early plantings, which have been sucplant organ in experimental plots was determined. The relationship cessful in certain areas, are not applicable in all areas among the genotypes was observed by means of a phenogram and of Turen due to the existence of heavy soils that do not the respective analyses of principal coordinates. Significantly different allow early mechanization. Therefore, identification and characterizations were found on the 19x10 and 43x32 genotypes. An management of sesame with genetic resistance to this analysis of principal components was conducted with metabolites in the leaves and the values of foliar acidity. This analysis separated the whitefly emerges as a valid method of control. genotypes 19x10 and 43x32 from the other genotypes with the lowest Plant resistance mechanisms to insects can be classifoliar acidity values. These two genotypes harbored the lowest incified as those producing adverse effects on insects (antidence of eggs and nymphs of whiteflies (nearly 10 and 50% of the biosis); those producing repellence, avoiding contact total incidence in the other genotypes), demonstrating the importance with the plant (antixenosis); and those compensating of foliar acidity values of sesame as resistance mechanisms against injury caused by insects (tolerance), allowing the plant whiteflies.

The aim of this study was to identify resistance to bacterial halo blight in Arabica coffee lines carrying Coffea racemosa genes. Eighteen Arabica coffee lines derivative from the genotype C1195-5-6-2, and the cultivars IAPAR 59 and IPR 99 were evaluated for resistance to bacterial halo blight in two trials carried out in field conditions, in Londrina, PR, Brazil. The cultivars Mundo Novo IAC 376-4 and Catuaí Vermelho IAC 81 were included as susceptible controls. Ten lines and the cultivar IAPAR 59 showed resistance to bacterial halo blight. The cultivar IPR 99 presented intermediate reaction, and the controls were very susceptible. This is the first study to show that lines derivative from the genotype C1195-5-6-2, which has C. racemosa genes, could be a source of resistance to bacterial halo blight in coffee breeding programs.

<p><strong> </strong>O objetivo desse estudo foi identificar cafeeiros com ciclo de maturação precoce e muito precoce com alta produtividade, em progênies de café arábica portadoras de genes de <em>C. racemosa</em>. O experimento de campo foi instalado no IAPAR, em setembro de 2007, em Londrina, PR, Brasil. O delineamento experimental foi em blocos ao acaso, com três repetições e parcelas de cinco plantas no espaçamento de 2,5 x 0,5 m. Foram avaliadas 17 progênies F1RC6 derivadas de retrocruzamentos de diferentes genótipos de café arábica com uma planta F2 do genótipo C1195-5-6-2. Como padrões comparativos foram utilizadas as cultivares IAPAR 59, IPR 99 e Catuaí Vermelho IAC 81 que possuem, respectivamente, ciclos de maturação semiprecoce, semitardio e tardio. Foram avaliadas as características produção, vigor vegetativo e ciclo de maturação dos frutos. As avaliações de maturação e vigor foram realizadas através de escala de notas e a produtividade em volume de frutos. As progênies H0509, H0501, H0518, H0513, H0508, H0510, H0505, H0506, H0514 e H0504 foram mais precoces do que seus parentais. Entre elas, as progênies H0518, H0507 e H0508 foram mais produtivos do que as testemunhas e não diferiram estatisticamente quanto ao vigor vegetativo. Foram identificadas 10 progênies F1RC6 de café arábica, portadoras de genes de <em>C. racemosa</em> com potencial para se tornarem cultivares com ciclo precoce e muito precoce. A característica de ciclo precoce de maturação dos frutos de <em>C. racemosa</em>, presente no C1195-5-6-2, permaneceu após os diversos ciclos de cruzamento com <em>C. arabica</em>.<strong></strong></p>

The aim of this study was to assess the resistance to red mite (Oligonychus ilicis) in Coffea arabica genotypes with introgression of genes from a different species (Coffea racemosa). The experiment was conducted in a greenhouse at IAPAR (Londrina, PR, Brazil), between January 2016 and January 2017. The experiment was conducted in a completely randomized design with five genotypes, 12 replications of one plant per plot. The C. arabica cultivars IPR 100, IPR 99 and IPR 103 were evaluated as well as an F4 Arabica coffee line IAPAR H0113-40-26-10 with introgressed C. racemosa genes. Catuaí Vermelho IAC 99 cultivar, which is a pure C. arabica, was used as a susceptible control. In conditions of high natural infestation of red mite, the resistance of coffee genotypes was evaluated using a standard visual evaluation in January 2017. This evaluation was based on the percentage of leaf area with typical symptoms caused by this mite. Only one genotype, the F4 line IAPAR H0113-40-26-10 showed resistance to the red mite because present less leaf area with symptoms compared to other genotypes. The Arabica coffee cultivars IPR 99, IPR 100 and IPR 103 are as susceptible to red mite as to the susceptible control Catuaí Vermelho IAC 99.