A quantitative review of soybean responses to waterlogging: agronomical, morpho-physiological and anatomical traits of tolerance

The impact of waterlogging on crops has increased during the last decades due to climate change, being considered the second most important abiotic stress after drought in soybean, with yield reductions of up to 80%. In this review, we performed a quantitative review from 54 papers about waterlogging effects in soybean. Yield losses are greater (57%) with waterlogging occurring at reproductive stages between R1 and R3 compared to vegetative stages, which is mostly related to a diminished number of pods per plant. Waterlogging impacts on biological nitrogen fixation, with losses of about 30 and 50% in nodule number and weight, with the greatest reductions in reproductive stages. The nitrogenase activity is drastically reduced with water excess but can quickly restore after. Losses in photosynthesis are about 30–50%, mostly related to reduced stomatal conductance and poor N status. Soybean can also develop aerenchymatous tissue in roots, hypocotyls and nodules, which may alleviate the anoxia generated by waterlogging by facilitating oxygen transport. Further efforts should be invested in investigating the effect of waterlogging on nodulation and the impact and subsequent recovery of root growth.Fil: Ploschuk, Rocio Antonella. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Miralles, Daniel Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Striker, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. University of Western Australia; Australi

Physiological responses and post - stress recovery in field - grown maize exposed to high temperatures at flowering

Neiff, Nicolás. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Departamento de Producción Vegetal. Corrientes, Argentina.Ploschuk, Edmundo Leonardo. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Cultivos Industriales. Buenos Aires, Argentina.Valentinuz, Oscar. Instituto Nacional de Tecnología Agropecuaria (INTA). Centro Regional Entre Ríos. Estación Experimental Agropecuaria Paraná (EEA Paraná). Paraná, Entre Ríos. Argentina.Andrade, Fernando Héctor. Instituto Nacional de Tecnología Agropecuaria (INTA). Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce (EEA Balcarce). Balcarce, Buenos Aires, Argentina.2053-2061Heat stress affects physiological traits and biomass production in major crops, including maize. We researched the responses of maximum efficiency of photosystem II (Fv/Fm), relative cell injury (RCI), stomatal conductance (gs), internal CO2 concentration (Ci), leaf photosynthesis (CER), and crop growth rate (CGR) in two maize cultivars exposed to high temperatures around silking (R1) under field conditions. Temperature regimes (i.e. control and heat) were performed during the pre-silking (–15d R1 to R1) and post-silking (R1+2d to R1+17d) periods. In the heat treatments, polyethylene shelters were used in order to increase daytime temperatures around midday (from 10 A.M. to 2 P.M.) during each period (i.e., pre- and post-silking). In the control treatments, the shelters remained open during the entire growing season. Gas exchange variables, Fv/Fm and relative cell injury (RCI) were measured on ear leaves. CGR was estimated based on biomass samples. CER and Fv/Fm presented maximum reductions at the end of the daytime heating. However, 30 min after the shelters were reopened, Fv/Fm of heated leaves reached values similar to controls, which were closely linked to CER recoveries. RCI was negatively associated with Fv/Fm, and cell injury increased gradually as heating continued. Ci was unaffected by heat treatment, indicating that gs was not the primary cause of CER reduction. Heat stress decreased CGR, and the reduction was positively associated with CER and Fv/Fm in both heating periods. We attempted to scale from cell to crop level and identify some physiological traits that could be helpful in breeding programs for heat stress tolerance

Waterlogging of Winter Crops at Early and Late Stages: Impacts on Leaf Physiology, Growth and Yield

Waterlogging is expected to increase as a consequence of global climate change, constraining crop production in various parts of the world. This study assessed tolerance to 14-days of early- or late-stage waterlogging of the major winter crops wheat, barley, rapeseed and field pea. Aerenchyma formation in adventitious roots, leaf physiological parameters (net photosynthesis, stomatal and mesophyll conductances, chlorophyll fluorescence), shoot and root growth during and after waterlogging, and seed production were evaluated. Wheat produced adventitious roots with 20–22% of aerenchyma, photosynthesis was maintained during waterlogging, and seed production was 86 and 71% of controls for early- and late-waterlogging events. In barley and rapeseed, plants were less affected by early- than by late-waterlogging. Barley adventitious roots contained 19% aerenchyma, whereas rapeseed did not form aerenchyma. In barley, photosynthesis was reduced during early-waterlogging mainly by stomatal limitations, and by non-stomatal constraints (lower mesophyll conductance and damage to photosynthetic apparatus as revealed by chlorophyll fluorescence) during late-waterlogging. In rapeseed, photosynthesis was mostly reduced by non-stomatal limitations during early- and late-waterlogging, which also impacted shoot and root growth. Early-waterlogged plants of both barley and rapeseed were able to recover in growth upon drainage, and seed production reached ca. 79–85% of the controls, while late-waterlogged plants only attained 26–32% in seed production. Field pea showed no ability to develop root aerenchyma when waterlogged, and its photosynthesis (and stomatal and mesophyll conductances) was rapidly decreased by the stress. Consequently, waterlogging drastically reduced field pea seed production to 6% of controls both at early- and late-stages with plants being unable to resume growth upon drainage. In conclusion, wheat generates a set of adaptive responses to withstand 14 days of waterlogging, barley and rapeseed can still produce significant yield if transiently waterlogged during early plant stages but are more adversely impacted at the late stage, and field pea is not suitable for areas prone to waterlogging events of 14 days at either growth stage

Harvest date modifies seed quality and oil composition of Jatropha curcas growth under subtropical conditions in Argentina

One of the most currently promoted new crops for biodiesel productions the perennial species Jatropha curcas L. (Euphorbiaceae) due to its promising high seed yields with high oil concentrations (33–39%) and oil quality that reaching the international biodiesel standards. Although there have been different evaluations of genotypes growing under the same environmental conditions, revealing great variability for seed and oil quality, no reports are available about the effect environmental conditions during grain filling over such traits. The objectives of this work were to determine (i) the effect of harvest dates on seed quality and oil concentration, (ii) if such changes can be explained by the average temperature during grain filling and (iii) how harvest dates could affect biodiesel quality. An experiment was carried out during 29 months in experimental plots located in Formosa, Argentina. A systematic fruit harvest was conducted during 15 different dates on 10 plants with similar height (≈1.80m). Environmental conditions during the experiment were appropriate to create a broad individual seed weight range (326–752mg) and significant differences were found among harvest dates. Seed oil concentrations were significantly different among harvest dates with a maximum value of 38.7±0.6% on 08 August 2011 and a minimum of 19.6±1.8% on 17 March 2010. Oil concentration increased linearly as seed weight increased up to a value of 605mg, after which higher seed weight was not associated with greater seed oil concentration. Oil concentration was largely (r2=0.85) explained by the kernel percentage through a linear regression (y=−25.9+0.967x). Variations in seed weight and oil concentration were not associated with changes in average temperature during grain filling, suggesting that fluctuations in the source-sink relation through the growing season could explain the variations found among harvest dates. Temperature during seed filling period strongly affected oil composition and higher temperatures were associated with higher oleic acid and lower linoleic acid concentrations, although this effect generated only small effects on the biodiesel quality. Environmental conditions during grain filling modified seed quality and oil composition, while its concentration was not affected. This work reveals the existence of harvest dates effects on seed quality and oil concentration, although unrelated with the environmental conditions explored during grain filling period

LA INFLUENCIA DE LAS CONEXIONES VASCULARES XILEMÁTICAS DURANTE LA DETERMINACIÓN DEL MOMENTO DE COSECHA EN MAÍZ TARDÍO

En Argentina, el cultivo de maíz tardío se practica con bastante frecuencia para evitar que la floración ocurra durante un período de sequía, pero los productores se ven obligados a mantener el cultivo durante gran parte del otoño e invierno para lograr que los granos alcancen la madurez comercial. El objetivo de este trabajo fue avanzar en el conocimiento acerca del rol de la conexión xilemática en el proceso de pérdida de humedad de los granos, para lograr una mejor eficiencia de cosecha. Para ello se realizó un experimento de campo con dos tratamientos: uno testigo y otro con la base de la espiga cortada para interrumpir la conexión xilemática durante la ventana de cosecha. En ambos tratamientos, los rendimientos oscilaron los 10000 kg ha-1, pero la tasa de pérdida de la humedad relativa y absoluta durante la primera fase de desecado fue significativamente mayor en el tratamiento cortado. Esto determinó que la remoción de la conexión xilemática lograra alcanzar la madurez comercial a los 65 días de iniciada la ventana de cosecha, a diferencia del testigo cuya humedad era 10 puntos superior. Este trabajo proporciona una nueva base teórica para seleccionar y mejorar cultivares de maíz adecuados para la cosecha mecánica de granos.In Argentina, the cultivation of late-season corn is frequently practiced to avoid flowering during a drought period, but farmers are forced to maintain the crop through much of the autumn and winter to ensure that the grains reach commercial maturity. The objective of this study was to advance the understanding of the role of xylem connection in the grain moisture loss process, in order to achieve a better harvesting efficiency. For this purpose, a field experiment was conducted with two treatments: a control group and another with the base of the cob cut to interrupt the xylem connection during the harvesting window. In both treatments, yields ranged around 10,000 kg/ha, but the rate of relative and absolute moisture loss during the initial drying phase was significantly higher in the cut treatment. This resulted in the xylem connection removal achieving commercial maturity 65 days after the start of the harvesting window, in contrast to the control where moisture content was 10 points higher. This study provides a new theoretical basis for selecting and improving maize cultivars suitable for mechanical grain harvesting.Na Argentina, o cultivo de milho tardio é frequentemente praticado para evitar que a floração ocorra durante um período de seca, mas os produtores são obrigados a manter a cultura durante grande parte do outono e inverno para garantir que os grãos atinjam a maturidade comercial. O objetivo deste estudo foi avançar na compreensão do papel da conexão do xilema no processo de perda de umidade dos grãos, visando a obter uma melhor eficiência na colheita. Para isso, um experimento de campo foi realizado com dois tratamentos: um grupo de controle e outro com a base da espiga cortada para interromper a conexão do xilema durante a janela de colheita. Em ambos os tratamentos, os rendimentos variaram em torno de 10.000 kg/ha, mas a taxa de perda de umidade relativa e absoluta durante a fase inicial de secagem foi significativamente maior no tratamento cortado. Isso resultou na remoção da conexão do xilema, alcançando a maturidade comercial 65 dias após o início da janela de colheita, em contraste com o grupo de controle, onde o teor de umidade estava 10 pontos mais alto. Este estudo fornece uma nova base teórica para selecionar e melhorar cultivares de milho adequados para a colheita mecânica de grãos

Functional convergence of growth responses to shade and warmth in Arabidopsis

Shade and warmth promote the growth of the stem, but the degree of mechanistic convergence and functional association between these responses is not clear. We analysed the quantitative impact of mutations and natural genetic variation on the hypocotyl growth responses of Arabidopsis thaliana to shade and warmth, the relationship between the abundance of PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and growth stimulation by shade or warmth, the effects of both cues on the transcriptome and the consequences of warm temperature on carbon balance. Growth responses to shade and warmth showed strong genetic linkage and similar dependence on PIF4 levels. Temperature increased growth and phototropism even within a range where damage by extreme high temperatures is unlikely to occur in nature. Both cues enhanced the expression of growth-related genes and reduced the expression of photosynthetic genes. However, only warmth enhanced the expression of genes involved in responses to heat. Warm temperatures substantially increased the amount of light required to compensate for the daily carbon dioxide balance. We propose that the main ecological function of hypocotyl growth responses to warmth is to increase the access of shaded photosynthetic organs to light, which implies functional convergence with shade avoidance.Fil: Romero Montepaone, Sofía Iara. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Sellaro, Romina Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Hernando, Carlos Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Costigliolo Rojas, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Bianchimano, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Ploschuk, Edmundo Leonardo. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Cultivos Industriales; ArgentinaFil: Yanovsky, Marcelo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Casal, Jorge José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentin

Absorción de agua y rendimiento de maíz en campos bajos ¿Es el horizonte nátrico una limitante?

Los campos bajos son una de las últimas áreas de expansión de la frontera agrícola en nuestro país. Un ejemplo es la Cuenca del Salado, que es una región que en la última década mostró incrementos de la superficie sembrada con cultivos agrícolas. Este trabajo, investigó los patrones de absorción de agua del cultivo de maíz en suelos Natracuoles, bajo dos regímenes hídricos contrastantes. Se realizaron mediciones semanales de humedad gravimétrica y se comparó la evolución del agua disponible para el cultivo a lo largo del ciclo. El rendimiento y la biomasa total disminuyeron ante incrementos del PSI, el pH y la CE. El régimen hídrico no redujo los niveles de producción (8260 a 8872 kg ha-1). El horizonte A, alcanzó aportes de hasta 90% del agua disponible, mientras que el horizonte Bt solo aportó el 50%. Este horizonte, redujo 141 kg ha-1 los rendimientos de maíz por cada unidad de sodio intercambiable, pero no los limitó totalmente. Una parte del aporte hídrico al cultivo provino de capas más profundas del suelo, demostrando que el horizonte nátrico no limitó totalmente la profundidad efectiva del cultivo. Estos resultados abren nuevas perspectivas para el desarrollo de la agricultura en la región.Fil: Garello, F.J. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cuenca del Salado. Agencia de Extensión Rural Chascomus; ArgentinaFil: Aguero, M.A. Universidad Nacional de La Plata; ArgentinaFil: Crespo, M. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Cicchino, M.A. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cuenca del Salado. Agencia de Extensión Rural Chascomus; ArgentinaFil: Melani, Esteban. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cuenca del Salado. Agencia de Extensión Rural Chascomus; ArgentinaFil: Ploschuk, Edmundo. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Cultivos Industriales; ArgentinaFil: Taboada, Miguel Angel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instuto de Suelos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Missing domesticated plant forms: can artificial selection fill the gap?

In the course of their evolution, the angiosperms have radiated into most known plant forms and life histories. Their adaptation to a recently created habitat, the crop field, produced a novel form: the plant that allocates an unprecedented 30–60% of its net productivity to sexual structures. Long-lived trees, shrubs and vines of this form evolved, as did annual herbs. Perennial herb forms with increased allocation to asexual reproduction evolved, but there are no examples of perennial herbs with high sexual effort. We suggest that sowing seed into annually tilled fields favored shorter-lived herbs because of trade-offs between first-year seed production and relative growth rate and/or persistence. By propagating cuttings, people quickly domesticated tuber crops and large woody plants. Perennial herbs were too small to be efficiently propagated by cuttings, and the association between longevity, allogamy and genetic load made rapid domestication by sexual cycles unlikely. Perennial grain crops do not exist because they could not have evolved under the original set of conditions; however, they can be deliberately developed today through artificial phenotypic and genotypic selection

Sensibilidad al anegamiento en especies invernales en etapas tempranas y tardías : respuestas fisiológicas, de crecimiento y rendimiento a escala de planta y cultivo

Fil: Ploschuk, Rocío Antonella. Universidad de Buenos Aires. Facultad de Agronomía. Escuela para Graduados; Argentina.Esta tesis caracteriza rasgos ecofisiológicos de tolerancia al anegamiento en trigo,cebada, canola y arveja. Se comparan los efectos del anegamiento vegetativo y reproductivo a escala de planta y de micro-canopeo. A nivel de planta se analizó la tasa fotosintética (limitantes estomáticas y no estomáticas), biomasa aérea y radical, rendimiento por planta y componentes numéricos (número y peso de grano) y aerénquima radical. En micro-canopeo, se cuantificó el índice de área foliar (IAF), eficiencia de intercepción (ei), eficiencia en el uso de la radiación (EUR), biomasa aérea y rendimiento/m2 con componentes numéricos. Trigo presentó leves reducciones en rendimiento por planta (14-29%), manteniendo la fotosíntesis y generando aerénquima en raíces (20-22%), con leves caídas en biomasa (0-25% aérea, 10-34% radical) en ambos negamientos. El rendimiento/m2 no difirió entre tratamientos, manteniéndose (o recuperándose rápidamente) la ei y la EUR. Cebada y canola anegadas tempranamente redujeron el rendimiento por planta un 15-21%. Cebada mostró una fisiología foliar similar a los controles y presencia de aerénquima radical (14-19%) mientras que canola fue afectada durante el anegamiento, pero logró recuperarse a pesar de no generar aerénquima. Cebada tuvo rendimientos/m2 similares a los controles, y canola sólo los redujo un 17%. El anegamiento tardío conllevó un deterioro mayor en la fotosíntesis y crecimiento, con rendimientos por planta del 32 y 26% de los controles. A escala de micro-canopeo se generaron caídas irreversibles en IAF, ei y EUR, con rendimientos 42-69 % menores que los controles. Arveja mostró, en ambas escalas de análisis, reducciones irreversibles en todos los parámetros y pérdidas del 90% en rendimiento con ambos anegamientos. En suma, trigo resultó el más tolerante a ambos anegamientos, cebada y canola presentaron alta sensibilidad sólo frente al anegamiento tardío y arveja se mostró como el más sensible al anegamiento en general con rendimientos casi nulos.Doctorado en Ciencias Agropecuarias179 p. : tbls., grafs., fot