Evaluation of Argentine wild sunflower biotypes for drought stress during reproductive stage

As in several regions where sunflower production has moved to areas with limiting water availability, the search for water-stress tolerant genotypes has been intensified. Helianthus annuus ssp. annuus L. constitutes a potential genetic resource because it has naturalized in the semi-arid zone of central Argentina. The assessment of these genetic materials for water deficit tolerance is of interest because they may represent a source of genes for drought tolerance, useful to sunflower breeding. Drought resistant genotypes should be achieved using easily identified phenotypic traits. Parameters like leaf area are widely used to characterize the performance under stress. Leaf temperature is an easily measured physiological parameter that allows an indirect estimate of plant transpiration and is well correlated with water availability. Relative water content indicates the ability to retain water from the soil and expresses plant osmotic adjustment ability. Specific leaf area is a morphological parameter related to leaf thickness. The objectives of this study were to evaluate the drought tolerance of Argentine wild sunflower biotypes and identify morphological and physiological traits expressing differences between stressed biotypes. Wild biotypes were evaluated during three years in the experimental field of the Agronomy Department, Universidad Nacional del Sur, Argentina. Groups of 10-15 plants of each biotype were evaluated under two water conditions, drought (deficit supply) with drip irrigation to cover a half of the potential evapotranspiration during flowering, or with optimal water supply. Soil surface was covered with black polyethylene to exclude rainwater. Wild sunflower comprised five biotypes collected from different habitats in the semiarid region of Argentina. Crosses between the wild biotypes and inbred lines were also included every year. Inbred lines and a commercial hybrid (DK4000) were used as controls. Recorded traits were: plant height, stem diameter, petiole length, leaf area, leaf number, head number and reproductive surface. Leaf parameters were: relative water content (RWC), specific leaf area (SLA), canopy temperature (CT), and chlorophyll content (SPAD). A susceptibility index (SI) was obtained to compare the performance under water stress with that obtained in optimal conditions. Biotype evaluation and parameter characterization were performed separately for each year because water stress levels were different. Wild sunflower responses to water stress were different for all parameters among biotypes, except for plant height and petiole length. Wild biotypes had better RWC and lower SLA than cultivated biotypes. Under water stress wild biotypes showed higher values and greater range of RWC and SPAD than cultivated sunflower. Susceptibility index showed that leaf area of wild sunflower biotypes had lower stress susceptibility than cultivated sunflowers. Nevertheless, wild biotypes showed increased susceptibility to the remaining plant morpho-physiological parameters. RWC and CT had a significant relationship in wild sunflower biotypes under water stress. Drought tolerant type identification was complex because of the complex responses among parameters. Wild biotypes might have a physiological mechanism which allows higher RCA than cultivated sunflower under drought stress. The lower SLA under water deficit could be attributed to a greater leaf thickness and could be related with RCA. Lower leaf area reduction under stress in wild sunflower is an interesting trait that might be used to improve cultivated sunflower. As the RWC is related with CT under stress in wild biotypes, this trait evaluation allows the fast examination of a high number of plants. The assessment of Argentina wild sunflower biotypes for traits associated with drought tolerance has not yet been done. Their identification could increase sunflower crop yield under drought in semiarid regions.Fil: Fernández Moroni, Ivana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Fraysse, M.. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Presotto, Alejandro Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Cantamutto, Miguel Ángel. Instituto Nacional de Tecnología Agropecuaria; Argentin

A comparative study of invasive Helianthus annuus populations in their natural habitats of Argentina and Spain

Wild Helianthus annuus is native to North America but it naturalized in other parts of the world as well. Although the origin of exotic populations is uncertain, they have probably evolved very differently in different countries. To unravel the origin of invasive populations from Argentina and Spain, morphological and agro-ecological data of nine populations from central Argentina, six from Andalusia and one from Gerona were collected in their natural habitats during three exploration trips in 2007 and 2008. In Argentina wild H. annuus was found mainly in disturbed areas between roads and fences. In a few cases the populations were located on the margins of cultivated fields. The Argentinean populations are spread across more than 50,000 m2 at a density of about 25 plants m-2. In Spain, the populations were found mainly in croplands. The largest population covered about 1,500 m2 and comprised no more than 200 plants. The Argentinean populations had taller plants with a higher number of heads of small size, while the Spanish populations were characterized by bigger heads with wider ligules and bracts. Plants were shorter and leaf size was larger in Gerona than in Andalusia. Multivariate analysis differentiated populations from Argentina and Spain by many traits. Wild-crop gene flow is likely the source of genetic variation among them. In Argentina, the populations keep the appearance of early wild introductions, while the Spanish populations are weedier and probably originated from pollen contamination of commercial seed with wild plants or crop-wild hybrids.Fil: Poverene, Maria Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Cantamutto, M.. Universidad Nacional del Sur; Argentin

Autopolinización y su implicancia en la invasividad de Helianthus annuus ssp. annuus y H. petiolaris

Helianthus petiolaris and H. annuus are exotic invaders that have spread widely in central Argentina in the last 70 years. As other annuals of the same genus, these species are outcrossers bearing a sporophytic self-incompatible mechanism. We investigated the ability to self-pollinate in plants of five accessions of each species, its influence on some reproductive traits, and compared to the cultivated sunflower, in which breeding for self-compatibility has been very successful. Plants were allowed to self-pollinate in bagged heads, manually forced to self-pollinate or allowed to cross-pollinate. Although both invasive species were confirmed as self-incompatible, some plants within most accessions were able to self-pollinate. There was no significant interaction between accessions and pollination type for most traits, except for seed set which was attributed to interspecific introgression. The self-compatibility of some plants was transmitted to their progeny. No significant correlation between self-pollination and spread distance from the proposed entry point for the exotic species was found. The occurrence of self-compatible plants was demonstrated in both species and this fact could in part explain the high invasive ability of annual Helianthus species in Argentina.Helianthus petiolaris y H. annuus son invasores exóticos que se han extendido en el centro de Argentina en los últimos 70 años. Como otras anuales del mismo género, estas especies son de polinización cruzada y llevan un mecanismo de auto-incompatibilidad esporofítica. Se investigó la capacidad de auto-polinización en plantas de cinco colecciones de cada especie, su influencia sobre algunos aspectos reproductivos y en comparación con el girasol cultivado, en el que el mejoramiento para la auto-compatibilidad ha sido exitoso. Las plantas se auto-polinizaron con los capítulos tapados por bolsas, se auto-polinizaron de manera forzada manualmente o se permitió la polinización cruzada. Aunque ambas especies invasoras fueron confirmadas como auto- incompatibles, algunas plantas dentro de la mayoría de las colecciones fueron capaces de auto-polinizarse. No hubo interacción significativa entre las colecciones y el tipo de polinización para la mayoría de los rasgos, excepto para la producción de semillas que se debió a la introgresión interespecífica. La auto-compatibilidad de algunas plantas se transmitió a su descendencia. No se encontró una correlación significativa entre la auto-polinización y la distancia de propagación desde el punto de entrada propuesto para las especies exóticas. La aparición de las plantas auto-compatibles se demostró en ambas especies y este hecho podría explicar en parte la alta capacidad invasiva de las especies anuales Helianthus en Argentina.Fil: Gutierrez, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); ArgentinaFil: Rueda, Federico. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cantamutto, M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Poverene, Maria Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina. Universidad Nacional del Sur. Departamento de Agronomía; Argentin

Spontaneous hybridisation of wild and cultivated species in Argentina

Un proyecto checo-argentino sobre la investigación de poblaciones de recursos genéticos - parientes silvestres de cultivos, cultivos asilvestrados e híbridos espontáneos con especies cultivadas - en el territorio de ambos países, fue propuesto con el objetivo de recopilar información sobre su distribución y para recoger muestras de semillas para futuras investigaciones. Fueron encontradas plantas híbridas de girasol y sorgo en 11 localidades y se recolectaron muestras de herbario y semillas. Las localidades fueron caracterizadas ecológicamente y desde el punto de vista de su vegetación y se evaluaron los factores de amenaza como requisito previo para la planificación de conservación in situ. En total, 52 localidades fueron visitadas y se recolectaron 36 muestras, incluyendo parientes silvestres.Czech-Argentinean project on genetic resources population investigation – crop wild relatives, escapes from cultivation and spontaneous hybrids with cultivated species – on the territory of both countries, was proposed with an aim to gather information on their distribution and to collect seed samples for further research. Hybrid plants of sunflower and sorghum were found on 11 localities. Herbarium and seeds samples were collected. Found localities were characterised ecologically and from the point of view of vegetation, and threat factors were assessed as prerequisite for in situ conservation planning. The total number of visited sites was 52 and collected samples 36 including crop wild relatives.Česko-Argentinský projekt na výzkum populací genetických zdrojů - planých příbuzných druhů, zplanělých druhů a hybridů s kulturními druhy byl navržen s cílem shromáždit informace o rozšíření spontánních hybridů a sebrat semenné vzorky. Hybridní rostliny slunečnice a čiroku byly nalezeny na 11 lokalitách. Byly odebrány herbářové doklady a sebrána semena. Nalezené lokality byly charakterizovány ekologicky i vegetačně a byly posouzeny faktory ohrožení nezbytné pro plánování in situ konzervace. Celkem bylo navštíveno 52 lokalit s planými příbuznými druhy a sebráno 36 semenných vzorků.Fil: Holubec, Voytech. Výzkumný ústav rostlinné výroby. v.v.i.; EsloveniaFil: Vymyslický T.. Zemědělský výzkum. spol. s r. o; República ChecaFil: Poverene, Maria Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Cantamutto, M.. Universidad Nacional del Sur. Departamento de Agronomía; Argentin

Exploring environmental determinants of the geographic distribution of broomrape (Orobanche cumana Wallr.)

Broomrape is one of the most critical biotic constraints to sunflower crop production. In the most extended sunflower crop area of the world, distributed across Black sea region, this parasitic weed shows a high occurrence. The weed, originally from the Caucasus region, has progressively migrated to the South of the Eurasia continent. The actual invaded area reaches Spain, Israel, Kazakhstan, China, Mongolia and Iran. Due to the usual seed exchange between macro-regions it is not clear why this weed is absent in other extended sunflower crop area located in South America. It is possible that the invasive process could be limited by abiotic restrictions. With the aim to estimate the influence of environmental factors on the actual broomrape geographic distribution, we evaluated 14 sunflower habitats of Serbia with different levels of natural infection and nine natural habitats of wild sunflower in Argentina. The altitude, latitude, longitude, mean hottest month temperature, mean coolest month temperature, and average rainfall of 10 habitats from Serbia showed no differences between infected and non-infected soils. The natural initial infection of four soils from Serbia did not influence the Orobanche attack intensity in a greenhouse experiment with artificial inoculation. Soil texture, total N, humus and calcareous content, as well as pH, had no effect on Orobanche attack intensity. In the greenhouse experiment, Principal Components Analysis showed that Orobanche attack intensity (expressed as parasite plant number per sunflower plant) was inversely associated only with P availability (ALP2O5), but the linear relationship between both variables was not significant. When Argentinean habitats were included in the database, strong differences between invaded and not invaded areas were found regarding geographic localization, as expected. The invaded habitats differed by the coolest month mean temperature, but no significant differences were found for the remaining climatic parameters. Soil fertility and the texture of 13 soils with different natural Orobanche infection showed no differences between invaded and non-invaded habitats. A better understanding of the abiotic determinants of Orobanche geographic distribution could help to design management tools to prevent the continuous increase of the invaded area and to limit damage to sunflower in the regions presently affected by the weed

Orobanche cumana wallr. resistance of commercial sunflower cultivars grown in Argentina

La planta parásita Orobanche cumana Wallr. (jopo) es una de las mayores limitantes de la producción de girasol en los principales países productores del mundo. Sin embargo, está ausente en el centro de origen y en las áreas de cultivo de girasol en América. No ha quedado claro aún si la naturalización de O. cumana en los hábitats de girasol de Argentina está limitada por restricciones abióticas o por la resistencia de los cultivares comerciales. El objetivo de este estudio fue investigar la resistencia a O. cumana de los cultivares comerciales de girasol en Argentina. En general, más del 95% de los cultivares probados fue susceptible al ataque de jopo; solamente uno de ellos mostró completa resistencia a O. cumana. Esto descarta la posibilidad de considerar a la resistencia genética de los cultivares utilizados como la causa de la ausencia de jopo en Argentina. Por lo tanto, los estudios futuros deberían focalizarse en otros factores bióticos y abióticos que, por afectar el crecimiento y desarrollo del jopo, podrían ser responsables potenciales de la ausencia de este parásito en Argentina.The parasitic weed Orobanche cumana Wallr. (broomrape) is one of the major limiting factors in worldwide sunflower production. However, it is absent in the centre of origin and in the sunflower crop areas of América. It has not yet been elucidated if O. cumana naturalization in sunflower habitats in Argentina is restricted as a result of either abiotic constraints or resistance in grown commercial cultivars. The aim of the present study was to assess the degree of resistance of commercial sunflower cultivars grown in Argentina to O. cumana. More than 95% of the tested sunflower cultivars were, in general, susceptible to broomrape attack. Although three cultivars were found to evidence an acceptable response to broomrape attack, only one of them showed complete resistance to O. cumana. This disregards genetic resistance of grown cultivars as being the reason for the absence of broomrape in Argentina. In view of this, future studies should focus on other biotic and abiotic factors affecting broomrape growth and development which could be potentially responsible for the absence of O. cumana in Argentina.Fil: Miladinovic, D.. Institute of Field and Vegetable Crops; SerbiaFil: Dedic, B.. Institute of Field and Vegetable Crops; SerbiaFil: Quiroz, F.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Alvarez, D.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Córdoba. Estación Experimental Agropecuaria Manfredi; ArgentinaFil: Poverene, Maria Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; Argentina. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Cantamutto, M.. Universidad Nacional del Sur; Argentin

Hybrid sunflower seed yield, composition and deterioration after chemical desiccation

The impact of chemical desiccation on yield showed contrasting results depending on seed moisture content at the time of application. Its effects on seed deterioration are still unknown and could be modified by seed composition. Objectives were to evaluate the impact of chemical desiccation on: i) hybrid sunflower seed yield and composition at harvest time, ii) seed deterioration during long-term storage and iii) the relationship between seeds deterioration and oil or oleic acid content. Six hybrids including low, mid and high oleic were evaluated in three experiments. Two treatments were applied on female lines at 27-30% seed moisture: (i) spraying with Paraquat and (ii) detaching heads with a knife. Control remained in the field until 10% seed moisture. Seeds were stored during 19 months under room and cold chamber conditions. Yield, number of seeds and hybrid seed composition (thousand seed weight, kernel percentage, oil and acid oleic content) were determined. Seed deterioration during storage was analyzed by germination and vigour. Paraquat advanced harvest by 35-43 days, without affecting yield or seed composition. During storage the germination of Paraquat treatments remained above that of control, without differences between storage conditions, while vigour remained above control only in cold chamber, for low oleic hybrids. Associations between deterioration (germination and vigour) and oil or oleic acid content, were not significant. Desiccation with Paraquat allows advanced harvest without yield losses or modifications in seed composition. The deterioration of desiccated seeds was lower and independent from oil and oleic acid content.EEA Hilario AscasubiFil: Szemruch, C.L. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; Argentina. Universidad de Lomas de Zamora. Facultad de Ciencias Agrarias. Instituto de Investigación sobre Producción Agropecuaria, Ambiente y Salud; ArgentinaFil: Cantamutto, Miguel Angel. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi; Argentina. Universidad de Lomas de Zamora. Facultad de Ciencias Agrarias. Instituto de Investigación sobre Producción Agropecuaria, Ambiente y Salud; ArgentinaFil: García, F.A. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Aguirre, M. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Renteria, S.J. Advanta Semillas; ArgentinaFil: Rondanini, D.P. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Tecnológicas; Argentina. Universidad de Lomas de Zamora. Facultad de Ciencias Agrarias. Instituto de Investigación sobre Producción Agropecuaria, Ambiente y Salud; Argentin

Acelerando el secado de girasol mediante desecantes químicos

El girasol (Helianthus annuus) es el segundo cultivo oleaginoso en importancia en el país, después de la soja. El retraso en la cosecha de girasol produce pérdidas económicas, tanto de productividad como de calidad. La madurez fisiológica ocurre con 38% de humedad de los granos. La consiguiente pérdida de verdor y humedad del cultivo, permite alcanzar la madurez adecuada para la cosecha.Fil: Rondanini, Deborah Paola. Universidad Nacional de Lomas de Zamora; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garcia, F. A.. Universidad Nacional de Lomas de Zamora; ArgentinaFil: Aguirre, M.. Universidad Nacional de Lomas de Zamora; ArgentinaFil: Marco, L.. Universidad Nacional de Lomas de Zamora; ArgentinaFil: Mazo, C.. Universidad Nacional de Lomas de Zamora; ArgentinaFil: Renteria, S.. Universidad Nacional de Lomas de Zamora; ArgentinaFil: Cantamutto, Miguel Angel. Universidad Nacional de Lomas de Zamora; ArgentinaFil: Szemruch, C.. Universidad Nacional de Lomas de Zamora; Argentin

Influencia del tamaño de la semilla de trigo y sus reservas proteicas : II- el rendimiento de grano del cultivo subsecuente

p.17-24Para probar que se pueden obtener aumentos de rendimiento utilizando semillas grandes, se seleccionaron lotes del cv. Cooperación Cabildo que provenían de una red de fertilización y presentaban un rango de entre 18 y 40 g las mil semillas, y entre 9 y 18 por ciento de proteína. Con ellas se sembraron tres ensayos en dos años. El rendimiento se correlacionó positivamente con el peso de mil granos y negativamente con el porcentaje de proteína. No se obtuvo correlación del rendimiento con el peso seco de las plántulas ni con el porcentaje de emergencia. Ese mayor rendimiento se debió al incremento del número de espigas por m2

Impacto de la “chinche diminuta” (Nysius sp.) sobre el cultivo de girasol del valle bonaerense del Río Colorado durante 2014/15

Los cultivos de girasol fueron afectados por la denominada “chinche diminuta” que no era considerada plaga. El ataque ocurrió luego de un invierno con escaso número de heladas, lluvias por encima de la media y primavera seca. La chinche diminuta se ubicó preferentemente entre las flores del disco, aunque también lo hizo entre las filarias (brácteas), hojas superiores y el segmento superior del tallo. En el período indicado se alcanzó una incidencia superior a 80 individuos por capítulo. Cuando la floración se atrasó a febrero, la incidencia fue menor a 20 individuos por capítulo.EEA Hilario AscasubiFil: Renzi Pugni, Juan Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi; ArgentinaFil: Reinoso, Omar Juan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi; ArgentinaFil: Bruna, Matias Nicolas. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi; ArgentinaFil: Vasicek, Juan Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi. Agencia de Extensión Rural Medanos; ArgentinaFil: Avalos, M. Asesor privado; ArgentinaFil: Oquiñena, Ariel. Asesor privado; ArgentinaFil: Cantamutto, Miguel Angel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi; Argentina