Evaluación agronómica de líneas avanzadas de fríjol voluble Phaseolus vulgaris L. en Paipa, Boyacá

En Boyacá la oferta de germoplasma de frijol mejorado es baja. El objetivo de este estudio fue evaluar el comportamiento agronómico de 18 líneas avanzadas volubles de frijol, procedentes del CIAT. Se utilizó el diseño bloques completos al azar, con tres repeticiones, incluyendo Bola Roja, Bolívar y Cargamanto como testigos. Se evaluó días a floración, vigor de crecimiento, días a madurez, incidencia de enfermedades, número de vainas/planta, número de granos/vaina, peso de 100 granos y rendimiento. Los genotipos MAC27, MAC13, MBC26, MBC28 y MBC37 no se diferenciaron del Cargamanto pero sí mostraron ser más precoces que Bola Roja y Bolívar. En días a madurez MAC27 y MBC39 fueron más tempranos que los testigos. Todos los genotipos se comportaron como resistentes a enfermedades, excepto MBC30 que resultó susceptible a Uromyces phaseoli y MBC33 a Phoma exigua. En número de vainas por planta, número de granos por vaina, peso de 100 semillas y rendimiento se destacaron MAC27 y LAS399, sin diferencia significativa frente a Cargamanto pero si superando a Bola Roja y Bolívar. Pese al efecto de las heladas en la fase final del ciclo, LAS399, MAC27 y Cargamanto produjeron rendimientos de 1300, 1038 y 950 kg/ha, respectivamente, mostrando las ventajas de su precocidad, en comparación a Bola Roja y Bolívar que son tardíos. Se concluye que LAS399 y MAC27, por su alta precocidad y resistencia a patógenos, son las líneas más promisorias para continuar la evaluación respecto a la posibilidad de ampliar la oferta de germoplasma de frijol voluble en Boyacá.

INTENSITAS DAN LAJU INFEKSI PENYAKIT KARAT DAUN Uromyces phaseoli PADA TANAMAN KACANG MERAH

ABSTRACT Rust leaf on red bean is major desease in the area of Tonsewer, Toure dan Tumaratas village. The aim of the study was to determine the intensity and infection rate of rust disease on red bean at Tonsewer, Toure and Tumaratas village, The method used was survey by drawing a diagonal line at four points and one point in the center of each farm. Hence, there were five points that were used for sampling area for calculating the intensity and the infection rate caused by leaf rust Uromyces phaseoli. The result showed that red bean farm in the village of Tonsewer, Toure and Tumaratas had been infected by rust disease caused by the fungus Uromyces phaseoli . The average of attacking intensity was 62.29% in Tonsewer. Whereas, Toure and Tumaratas were 61.71% and 62.29 respectively. The average of infection rate was 0.239 per unit per day in the Tonsewe. While in the Toure and Tumaratas were 0.189 and 0.208 per unit per day respectively . Keyword : Intensity and infection rate,Red Bean

Effect of Ascorbigen and 1′-Methylascorbigen on Disease Resistance of Bean Plants to Uromyces Phaseoli

The effect of ascorbigen and 1′-methylascorbigen on the disease resistance of bean (Phaseolus vulgaris L.,. cv. Debreceni Tarka) to the fungal pathogen Uromyces phaseoli Pers. is reported. Contrary to ascorbigen, pretreatment of bean plants with 1′-methylascorbigen, as in the case of other endogenous N-, O- and S-methyl compounds, induced the double immune response leading to the biochemical immunization of plants. The effectiveness of protection depended on the dosage of the applied 1′-methylascorbigen and on the time interval between the chemical pretreatment and inoculation. Results of our greenhouse experiments revealed, in accordance with previous results, that the presence of the N-methyl group in the 1′-methylascorbigen molecule is the precondition of the effect, and formaldehyde formed from this N-methyl group and its reaction products (e.g. singlet oxygen, ozone) can have a determining role in the manifestation of the effect.

First Report of Soybean Rust Caused by Phakopsora pachyrhizi on Phaseolus spp. in Argentina

Asian soybean rust (ASR), caused by Phakopsora pachyrhizi Syd. & P. Syd., has been reported in Argentina on soybean (Glycine max) and kudzu (Pueraria lobata and Pueraria javanica) since the 2002 growing season (1–4). On 29 May 2006, plants of Phaseolus spp. were found to have tan ASR-like rust lesions on leaves at eight different field plots located in the northwestern province of Salta, Argentina. Growth stages of infected bean plants within plots were between pod setting and physiological maturity. Diagnosis of ASR on bean leaves was performed with a stereoscopic microscope to view rust pustules, and suspected uredinia of P. pachyrhizi were observed, furthermore, typical ASR urediniospores also were also observed at ×400. ELISA and PCR methods gave positive results for ASR. Rust spores from these plants were used to inoculate soybean plants at the V3 growth stage with rust spores from field bean plants produced under greenhouse conditions. Typical ASR tan pustules developed within 21 days of inoculation. Bean rust caused by Uromyces phaseoli also was seen in some of the bean plots but was easily differentiated from ASR because the uredinia were much darker and affected the upper leaves, while the ASR uredinia were lighter and spread from the lower leaves to the upper leaves. This finding is of significance in Argentina because bean is an important crop grown in the northwestern region of the country and is planted approximately 2 months after soybean planting. Given this planting time difference, bean may provide an overwintering host for the survival of ASR spores, thereby providing a green bridge for infection of soybean plants during the following growing season. References: (1) A. J. Ivancovich. Soybean rust situation in Argentina. Oral presentation. Symposium: Soybean Rust: Too Close for Comfort. Annual Meeting of the American Phytopathological Society. 2003. (2) A. J. Ivancovich. Plant Dis. 89:667, 2005. (3) A. J. Ivancovich and G. Botta. Rev. Tecnología Agropecuaria 7(21):16, 2002. (4) A. J. Ivancovich et al. Phytopathology (Abstr.) 94(suppl.):S44, 2004.

EFEITO DE DIFERENTES FUNGICIDAS NO CONTROLE DE FERRUGEM E OÍDIO NAS CULTIVARES "CARIOCA" E "GOIANO PRECOCE" DE FEIJOEIRO COMUM

RESUMO Este experimento foi conduzido com o objetivo de avaliar a eficiência do Tiofanato Metílico, Chorotalonil e Tiofanato Metílico + Clorothalonil no controle de ferrugem (Uromyces phaseoli) e oídio (Erysiphe polygoni) nas cultivares "Carioca" e "Goiano Precoce" de feijoeiro comum. O delineamento experimental foi o de blocos ao acaso com oito tratamentos e quatro repetições. A aplicação dos fungicidas foi feita com atomizador do tipo costal e volume de calda de 300 litros/hectare. Os estádios da cultura em que foram realizadas as aplicações foram V4 (terceira folha trifoliolada), R5 (pré-floração) e R8 (enchimento de vagens). Os parâmetros utilizados para avaliação foram o rendimento de grãos e severidade das doenças. A aplicação de fungicidas possibilitou uma redução acentuada na severidade das doenças e um aumento no rendimento de grãos.