Revista industrial y agrícola de Tucumán

Productivity and disease tolerance of TUC 95-37, a new sugarcane (Saccharum spp.) variety in Tucumán, Argentina

En este trabajo se presenta el comportamiento productivo y fitosanitario del nuevo cultivar de caña de azúcar (Saccharum spp.) TUC 95-37, obtenido y seleccionado por el Programa de Mejoramiento Genético de la Caña de Azúcar de la Estación Experimental Agroindustrial Obispo Colombres (Tucumán, R. Argentina). La información que se presenta proviene de 24 cosechas realizadas en ensayos con 18 genotipos, implantados de acuerdo a un diseño experimental de bloques completamente aleatorizados con tres repeticiones. Los ensayos se replicaron en seis localidades de Tucumán y fueron evaluados en cuatro edades de corte (caña planta, soca 1, soca 2 y soca 3) entre los años 2002 y 2005. Las variables toneladas de caña/ha y de azúcar/ha y rendimiento fabril porciento se evaluaron en mayo. Para cada variable, edad y localidad se realizaron análisis de la varianza y pruebas de comparación de medias. También se aplicó la metodología de GGE biplot como herramienta gráfica, para identificar genotipos superiores y estables frente a distintos ambientes de expresión. Se evaluó además el comportamiento fitosanitario de TUC 95-37. Los resultados indicaron que la nueva variedad evidenció un comportamiento productivo similar al de LCP 85-384 en la mayoría de las edades de corte y localidades evaluadas. En caña planta, el nuevo cultivar fue el genotipo más productivo, presentando además una amplia adaptación a diferentes ambientes. En soca 1 y 2, TUC 95-37 resultó segunda en orden de mérito, siendo estable en las diferentes localidades. En soca 3, la nueva variedad evidenció una menor estabilidad frente al ambiente. Con respecto al comportamiento fitosanitario, TUC 95-37 se comportó como moderadasmente resistente a roya marrón (Puccinia melanocephala), a escaldadura de la hoja (Xanthomonas albilineans) y a carbón (Sporisorium scitamineum). Se mostró moderadamente susceptible al mosaico (Sugarcane mosaic virus) y a estría roja (Acidovorax avenae). Como la gran mayoría de la variedades de caña de azúcar que se cultivan en el mundo, la variedad TUC 95-37 mostró susceptibilidad al raquitismo de la caña soca (Leifsonia xyli subsp. xyli).

This paper reveals the results of studies conducted to evaluate the productivity and tolerance to diseases of TUC 95-37, a new sugarcane (Saccharum spp.) cultivar obtained and selected by the Sugarcane Breeding Program of Estación Experimental Agroindustrial Obispo Colombres (Tucumán, Argentina). Data in this work derived from 24 harvests in trials with 18 genotypes, planted according to a completely randomized block design with three repetitions, with replicates at six different sites in Tucumán. TUC 95-37 was assessed at four different crop ages (plant cane, first, second and third ratoons), through the 2002 and 2005 crop seasons. For each variable, age and location, the analysis of variance and comparison of means tests were performed. GGE biplot methodology was used as a graphic tool to identify superior and stable cultivars in different environments. In addition, disease resistance levels were evaluated. Productivity data (crop yield, factory yield percentage in May, and sugar production per ha) showed that TUC 95-37 was as productive as LCP 85-384 at most of the crop ages and sites considered. TUC 95-37 turned out to be the best or most productive among genotypes and a very stable variety at plant cane, also ranking as the second best variety, as well as a very stable one, at first and second ratoon ages. However, at third ratoon TUC 95-37 showed lower stability in different environments. As regards its response to diseases, this new cultivar proved to be moderately resistant to brown rust (Puccinia melanocephala), leaf scald (Xanthomonas albilineans), and smut (Sporisorium scitamineum). Nonetheless, TUC 95-37 was moderately susceptible to mosaic (Sugarcane mosaic virus) and red stripe (Acidovorax avenae) and, as most sugarcane varieties planted in other parts of the world, it presented susceptibility to ratoon stunting disease (Leifsonia xyli subsp. xyli).

Monitoring of effluent particulate matter emitted by sugarcane factory stacks in Tucumán

Durante las moliendas en los años 2008, 2009, 2010 y 2011, se realizaron mediciones de las concentraciones de material particulado total (MPT) en las emisiones de chimeneas de calderas de la industria azucarera, en Tucumán, R. Argentina. El objetivo de este trabajo fue monitorear la evolución de la concentración y emisión de MPT y observar la influencia de los sistemas de filtrado instalados en las chimeneas de las mencionadas unidades. Se ilustran los datos de las emisiones de MPT obtenidas en los años indicados, con valores promedio por caldera de 58,5 kg/h, 33,6 kg/h, 47,6 kg/h y 33,9 kg/h, respectivamente. Asimismo, este estudio muestra un seguimiento minucioso de un grupo de calderas bagaceras, para determinar la evolución de las emisiones en función de las variables de operación características de esas calderas. Los resultados demostraron la influencia del mantenimiento y de la correcta operación de los equipos de filtrado en la calidad de los gases que fluyen por las chimeneas. Se estudió la influencia de los índices característicos de diseño de los lavadores de gases en la concentración de partículas. Se observó que se ha logrado un menor impacto ambiental a lo largo del tiempo analizado.

Total particulate matter (TPM) concentrations were measured in stack fumes from sugar factory steam generating boilers in Tucumán in 2008, 2009, 2010 and 2011. The objective of this work was to monitor the evolution of TPM concentrations and emissions and observe the efficiency of filtration systems used in sugarcane factory stacks. Average values of 58.5 kg/h, 33.6 kg/h, 47.6 kg/h and 33.9 kg/h were obtained in 2008, 2009, 2010 and 2011, respectively. Bagasse boilers were also meticulously surveyed to obtain data of the evolution of emissions in relation to specific operation variables of the boilers. Data concerning the quality of effluent gasses from the stacks demonstrated the influence of maintaining and correctly using filtration media. Decrease in particle concentration was studied in relation to design indices of gas washers, and it was observed that the technological advances introduced into sugar mill equipment design have led to a lesser environmental impact.

New soybean cultivar released by the EEAOC: Yanasu RR

Durante las últimas décadas, el cultivo de la soja a nivel mundial tuvo un crecimiento tanto en superficie, como en productividad. En la Argentina sucedió de igual manera, particularmente a comienzos de este siglo, como resultante del uso de alta tecnología, convirtiendo a este cultivo y a sus subproductos en el pilar del sistema granario y exportador. El desarrollo del Noroeste Argentino (NOA) coincidió con el proceso a nivel nacional. La Estación Experimental Agroindustrial Obispo Colombres (EEAOC) de Tucumán buscó permanentemente producir cultivares adaptados a esta zona, siendo este el principal objetivo del subprograma Mejoramiento Genético del Proyecto Soja. Yanasu es una nueva variedad de soja liberada por la EEAOC, que completa su madurez fisiológica a los 123 días de su siembra (pertenece al grupo de madurez VIII corto) y que logra excelentes potenciales de rendimiento. Fue obtenida a través de cruzamiento y posterior avance generacional en la subestación de Monte Redondo (San Agustín, Tucumán). Yanasu RR fue sometida a ensayos comparativos de rendimiento (ECR) en cuatro diferentes sitios del área sojera tucumana durante la campañas 2005/2006 y 2006/2007, alcanzando rendimientos superiores a los testigos en la mayoría de los ensayos. Exhibe, entre otras características, baja o nula dehiscencia de vainas y un peso de 1000 semillas de 162,6 gramos. En cuanto a su sanidad, se destaca su tolerancia a las enfermedades cancro del tallo y mancha ojo de rana, así como ante patógenos de semillas como Cercospora kikuchii, Alternaria spp. y Macrophomina spp. Desde 2009/2010 se la incluyó en la Red de Evaluación de Variedades Comerciales del NOA, destacándose por encima del testigo en 12 localidades de la región, con un excelente potencial de rendimiento.

In recent decades, soybean planted area, production, and productivity have increased worldwide. This has also occurred in Argentina, especially during the last century, based on the use of high technology, which has turned this crop and its products into the cornerstone of grain and exportation systems. The development of this crop in North Western Argentina has coincided with the process at the national level. Estación Experimental Agroindustrial Obispo Colombres (EEAOC) from Tucumán is constantly producing new technology, partly through the generation of new varieties adapted to this area. Yanasu is a new soybean variety released by the EEAOC, with 123 days to physiological maturity (it belongs to early maturity group VIII) and excellent yield potential. It was obtained by parental crossing and subsequent generation advance at Monte Redondo sub-station, in San Agustín, Tucumán. Comparative yield trials were conducted at four different sites in the soybean area in Tucuman during the 2005/2006 and 2006/2007 seasons. Yanasu presented higher yields than the control in most trials. Among other characteristics, it showed very good resistance to shattering and lodging and a 1000 seed weight of 162.6 grams. As for its sanitary conditions, it exhibited an outstanding tolerance to stem canker disease and frog eye spot, as well as to seed pathogens such as Cercospora kikuchii, Alternaria spp. and Macrophomina spp. Since the 2009/2010 season, Yanasu has been included in the evaluation network of commercial varieties in North Western Argentina, and has proven to have an excellent yield potential, outdoing that of the control at over a dozen sites in the region.

Evaluation of soil compaction under no tillage systems in the Chacopampeana Plain in Tucumán, Argentina

La siembra directa puede ocasionar la compactación de la capa superficial del suelo por falta de remoción y por tránsito de maquinarias. El uso de equipos descompactadores puede disminuir este efecto. En cuatro localidades de la Llanura Chacopampeana de la provincia de Tucumán (R. Argentina), se seleccionaron cinco manejos de suelo en siembra directa de granos, para evaluar el grado de compactación y otras propiedades físicas del suelo: suelos "nuevos", de menos de cinco años de agricultura en siembra directa (N); suelos de más de 10 años de siembra directa, con soja continua (SS); suelos de más de 10 años de siembra directa, con soja continua y rotación soja/maíz (SM); suelos de más de 10 años de siembra directa, con soja continua y laboreo vertical profundo previo a la siembra (SS+LVP) y suelos de más de 10 años de siembra directa, rotación soja/maíz y laboreo vertical profundo previo a la siembra (SM+LVP). Los parámetros evaluados fueron: densidad aparente (Dap), densidad aparente máxima (Dap max) y densidad aparente relativa; resistencia a la penetración (RP); cobertura de rastrojos; tasa de infiltración (I) y materia orgánica (MO). En la capa superficial del suelo, la MO fue significativamente mayor en N que en SS y SS+LVP, mientras que SM y SM+LVP mostraron valores intermedios. Los manejos con LVP tuvieron una cobertura superficial significativamente menor que aquellos sin LVP. A su vez, SM siempre tuvo mayor cobertura que SS. Hasta los 20 cm de profundidad, la Dap superficial fue mayor en los manejos sin LVP, excepto en N. En la mayoría de los sitios y manejos, la Dap relativa no superó el 90%. En todos los sitios, RP fue menor en SS+LVP y SM+LVP que en SS y SM, respectivamente. Las tasas de infiltración (I) fueron mayores en los suelos con LVP, que en aquellos sin laboreo. Sin embargo, N tuvo la tasa de infiltración más alta, probablemente debido a la conservación del sistema poroso. Se deben evaluar estas variables para decidir el uso de descompactadores de suelo.

No-tilled soils can cause topsoil compaction as a result of the lack of soil removal and of machinery traffic. Using subsoilers can reduce this effect. This study was carried out in grain fields located at four sites in the Chacopampeana Plain, province of Tucumán, Argentina. Five no-tillage soil management situations were evaluated in terms of soil compaction degree and other related soil physical properties. These situations were: 'new soils', under no tillage management for less than five years (N); more than 10 years under no tillage management, continuously planted with soybean (SS); more than 10 years under no tillage management and soybean/corn rotation (SM); more than 10 years under no tillage management, with deep vertical tillage prior to sowing, and continuously planted with soybean (SS + LVP); and soils of more than 10 years under no tillage management, soybean/corn rotation, and deep vertical tillage before sowing (SM + LVP). Parameters evaluated before sowing were: bulk density (Dap), maximum bulk density (Dap max), relative apparent density, penetration resistance (RP), crop residue, infiltration rate (I), and organic matter (OM). In topsoil, OM was significantly higher in N than in SS and SS + LVP, while SM and SM + LVP showed intermediate values. LVP showed significantly lower crop residues than those without LPV. In turn, SM had higher crop residues than SS. Upper 20 cm Dap was higher in all situations without LVP, except in N. In most situations, relative apparent density did not exceed 90%, considered critical for normal soybean root growth. RP was significantly lower in SS + LPV and SM + LVP than in SS and SM, respectively. Infiltration rates (I) were significantly higher in LPV than in those situations without tillage. However, N had the highest I, probably due to soil porous system conservation. It is advisable to quantify all these parameters before deciding to use deep tillage equipments.

The Citrus Sanitation Center of Estación Experimental Agroindustrial Obispo Colombres, six years after its establishment

The Citrus Sanitation Center was established in October 2004, in Tucuman province, Argentina with the main objective of establishing a virus-free and true-to-type source of budwoods of all the main citrus varieties and rootstocks in North Western Argentina. Its aim was also to ensure that citrus growers would be supplied with the best genetic citrus material, free from any harmful pathogens. At present, 25 citrus varieties and rootstocks have been recovered through the standard procedure of shoot-tip grafting in vitro, coupled with an intensive indexing program to make sure that they are free of graft-transmissible pathogens. Also, other 16 varieties and rootstocks will shortly be part of the foundation block. A field observation block for horticultural evaluation was established in 2006 as a duplicate of the virus free foundation block trees. In 2009, the first 72,600 certified budwood materials of the main lemon varieties were released. This paper is a brief report of the background and present status of the Citrus Sanitation Center, its current activities, technical advances, and plans for the future.

Natural spread of Citrus tristeza virus in lemon varieties

Natural spread of Citrus tristeza virus (CTV) was monitored in different lemon varieties derived from shoot tip grafted (STG) selections proven to be free of CTV before planting. The trial was planted in November, 2007, with a randomized four-block design with four replications. This experiment was originally established to compare selected clones with their duplicates recovered by STG. The selected clones were originally nucellar clones kept in the germplasm bank in the field for 30 to 40 years, so the plants were naturally infected with CTV. The lemon varieties tested were two lines of both Frost Eureka and Limoneira 8A Lisbon and one line of Feminello Santa Teresa and Genoa EEAT. Plants were grafted on Poncirus trifoliata Flying Dragon, except for Eureka lemon, which was grafted on 79 AC [Citrus reshni x (C. paradisi x P. Trifoliata)]. Direct immunoprinting-ELISA with 3DF1+3CA5 monoclonal antibodies (Plant Print Diagnostics, Valencia) was used to determine the presence of CTV in field samples. Each sample was composed of four young shoots collected from the four sides of each tree. Two diagnoses were performed, one in September 2009 and another in September 2010. STG trees showed significant differences in CTV infection among them. The variety most infected with CTV was Limoneria 8 A and the least infected was Feminello Santa Teresa. Infected plants were found in a random distribution in the plot. All selected lemon trees were CTV positive. CTV spread will be monitored until 100% of all varieties show positive.

Comparison of different diagnostic methods for detection of Hop stunt viroid and Citrus exocortis viroid in citrus

Viroids such as Hop stunt viroid (HSVd) and Citrus exocortis viroid (CEVd) are important pathogens in citrus plants. A comparative assay was performed to evaluate the viroid diagnostic techniques currently available at the Citrus Sanitation Center of Estación Experimental Agroindustrial Obispo Colombres. We compared the results obtained in the diagnosis of HSVd and CEVd in citrus using two molecular techniques: s-PAGE and RT-PCR and biological indexing. Biological indexing was performed in a greenhouse under controlled temperature, using Etrog citron Arizona 861-S1 grafted on rough lemon rootstock as the indicator plant. Tissue samples for s-PAGE were obtained from inoculated citrons used in the biological indexing tests, and DNA extraction was performed following published procedures. HSVd and CEVd specific primers were used for RT-PCR, and samples were taken directly from field plants and inoculated citrons. Two nucleic acid extraction methods were compared. A total of 12 viroid isolates collected from orange, citron, grapefruit, citrumelo and lime trees, mostly from North Western Argentina, were used in these assays. The three diagnostic methods compared gave similar results in 11 of 12 samples assayed. Several viroids were detected by s-PAGE and most of them were found as mixtures. HSVd and CEVd were identified by RT-PCR and no differences were found between the two extraction methods assayed. Sample R-407 was positive for exocortis with biological diagnosis and s-PAGE, but it was negative with RT-PCR. This was probably due to inefficient cDNA synthesis or to the presence of inhibitors that could interfere with the reaction. On the basis of the results obtained, it can be concluded that the three techniques assayed are complementary and useful tools for diagnosis and identification of HSVd and CEVd in citrus.