Assessment of sugarcane cultivars with stable reaction to Xanthomonas albilineans under mechanical inoculation conditions

Leaf scald caused by Xanthomonas albilineans in sugarcane is one of the most important diseases around the world since it causes severe losses in both agricultural and industrial yields. In Cuba, resistance to this disease is considered a major selection criterion within the breeding program. The aim of this work was to detect sugarcane cultivars with stable reaction to X. albilineans by using both additive main effects and multiplicative interaction (AMMI) and linear general models. For this, 16 cultivars planted simultaneously in 2015, 2016, and 2017 in two locations: Jovellanos (Matanzas) and Florida (Camagüey) in Cuba were mechanically inoculated with a bacterial isolate previously characterized by sequencing its DNA fragment. Disease severity was recorded in plant cane and first ratoon, and results were consistent in both analyses and revealed that L55-5 and C323-68 were the most susceptible cultivars and C1051-73 was the most resistant; however, C1051-73, C275-80, C86-12, C88-382, C89-147, My5514, and Ty86-28 were the most stable across the years and localities evaluated. Results will allow adapting the methodology for the evaluation of the reaction to leaf scald of new sugarcane cultivars.Fil: La O Hechavarría, María. Instituto de Investigaciones de la Caña de Azúcar; CubaFil: Puchades Izaguirre, Yaquelín. Instituto de Investigaciones de la Caña de Azúcar; CubaFil: Pérez Pérez, Yosel. Instituto de Investigaciones de la Caña de Azúcar; CubaFil: Michavila, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; ArgentinaFil: Casas González, Mario A.. Instituto de Investigaciones de la Caña de Azúcar; CubaFil: Pérez Pérez, Juana. Instituto de Investigaciones de la Caña de Azúcar; CubaFil: Carvajal Jaime, Omelio. Instituto de Investigaciones de la Caña de Azúcar; CubaFil: Montalván Delgado, Joaquín. Instituto de Investigaciones de la Caña de Azúcar; CubaFil: Peña Malavera, Andrea Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; ArgentinaFil: Mesa Lopez, José. Instituto de Investigaciones de la Caña de Azúcar; CubaFil: Castagnaro, Atilio Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; ArgentinaFil: Perera, María Francisca. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentin

First ratoon from cuttings or vitroplants free of Xanthomonas albilineans can be used as seed in sugarcane production

One of the factors that limits the production of sugarcane (Saccharum spp.) is the use of poor quality seed. The objective of the work was to demonstrate the feasibility of using the first ratoon from in vitro propagated plants or cuttings as seed with phytosanitary quality with respect to the presence of Xanthomonas albilineans, the causal agent of foliar scald. Two cultivars (C1051-73 and C90-469) and three types of planting plant material were used (one-bud cuttings, three-bud cuttings and vitroplants). The evaluations were carried out at 10 months of culture in the cane plant strain and first ratoon. The variables analyzed were serological diagnosis by UMELISA and staining of the xylem vessels for the presence of X. albilineans, agricultural yield and its components. In addition, the results of both strains were compared in the variables t cane ha-1, diagnosis by UMELISA and by staining of the xylem vessels. The results reflected that the cultivars and treatments did not show significant differences regarding the diagnostic methods used in the strains evaluated. The agricultural yield (t cane ha-1) was superior for the treatment with cuttings of three buds in cane plant and in ratoon it was for plants reproduced in vitro. The number of stems in the two strains increased in the propagation with vitroplants. In the comparison between the cane plant and first ratoon, there were only significant differences in agricultural yield and the percentage of functional vessels of the xylem, which were in favor of the ratoon. It was demonstrated the feasibility of using the first ratoon from vitroplants and cuttings, as seed with phytosanitary quality with respect to the presence of X. albilineans

Control Biológico del Salivazo de la Caña de Azúcar Aeneolamia sp. con el Nematodo Heterorhabditis bacteriophora y los Hongos Entomopatógenos Metarhizium anisopliae y Beauveria bassiana como Opción Económica y Sostenible

El nematodo entomopatógeno Heterorhabditis bacteriophora (Poinar) (Rhabditida: Heterorhabditidae) fue evaluado como opción potencial de control biológico del salivazo de la caña de azúcar, Aeneolamia spp. (Hemiptera: Cercopidae). Los estudios de campo muestran un control biológico efectivo utilizando este nematodo sobre los estadios ninfales del salivazo y cuyo efecto se hace evidente a pocas horas de haber sido aplicado. Hubo mayor mortalidad en los estadios ninfales 4 y 5 del salivazo y la toxicidad del nematodo se prolongó por semanas después de su aplicación en el campo. En algunos ensayos se observó superioridad estadística de H. bacteriophora sobre los hongos entomopatógenos Metarhizium anisopliae (Hypocreales: Clavicipitaceae) y Beauveria bassiana (Hypocreales: Cordycipitaceae) (Prueba de Tukey al 0.05 y 0.01 niveles de significancia), así como frente a otros agentes de control biológico alternativos.

Xanthomonas albilineans(Ashby) Dowson: cultivars susceptibility and effects in the sugar yield

The effects produced by the Xanthomonas albilineans (Ashby) Dowson on stalks with acute symptoms of the disease have been addressed by different authors, however, is unknown the effects that may occur in seropositive asymptomatic stems to the bacteria. This work has as objective to study the impact of the presence of bacteria in the colonized tissues, as well as the relationship between the concentration of cells and the expression of symptoms. In 900 stems of 14 cultivars detected the bacteria by serology and identified the variables Brix of stem with handheld refractometer, as well as the contents of fructose, glucose and sucrose whit High Performance Liquid Chromatographic. The presence of the bacterium X. albilineans in asymptomatic stems affects the sugar content of the same, which constitutes a contribution to the knowledge of the pathogen - host relations for this disease. The stems are colonized by the bacteria, but the amount of UFC/g of tissue or per ml/juice does not mean that a cultivar is more or less susceptible. In stalks with symptoms the cell density increases toward the foliage, while that in the asymptomatic happens to the contrary