Control ambiental y genético de la fenología del cultivo de soja : impactos sobre el rendimiento y la adaptación de genotipos

p.63-88El ajuste entre la fenología del cultivo de soja y el ambiente es uno de los principales aspectos que determinan la adaptación de los cultivares en las diferentes zonas de producción y condicionan el rendimiento alcanzado. El ritmo con el que progresa el desarrollo y, por lo tanto, el momento en el que ocurren los estados más críticos del cultivo, se encuentran fuertemente condicionados por el fotoperíodo y la temperatura. Actualmente, las respuestas del cultivo de soja a estos factores están bastante bien comprendidas; asimismo, se ha avanzado en el conocimiento de las bases genéticas que condicionan las respuestas fenológicas de los cultivares. Frente a la complejidad de las relaciones entre el ciclo y el rendimiento del cultivo, estos conocimientos permiten identificar nuevas vías para mejorar la adaptación de los cultivares e incrementar el rendimiento del cultivo. En este artículo se presenta una revisión de los avances logrados en estos temas, a través de una perspectiva ecofisiológica

Regulación térmica y fotoperiódica del desarrollo de genotipos de soja verde y del crecimiento de sus granos

p.95-99Se evaluaron los efectos del fotoperíodo y la temperatura sobre el desarrollo del cultivo y el crecimiento de los granos en genotipos de soja verde Se realizaron experimentos a campo, incluyendo diferentes fechas de siembra en Buenos Aires y Taiwan. Sólo un genotipo resultó insensible al fotoperíodo mientras que los demás mostraron un respuesta de días cortos. Bajo fotoperíodos cortos se incrementó la tasa de crecimiento de los granos en cuatro de los genotipos y la temperatura ejerció una fuerte regulación

Soybean fruit development and set at the node level under combined photoperiod and radiation conditions

In soybean, long days during post-flowering increase seed number. This positive photoperiodic effect on seed number has been previously associated with increments in the amount of radiation accumulated during the crop cycle because long days extend the duration of the crop cycle. However, evidence of intra-nodal processes independent of the availability of assimilates suggests that photoperiodic effects at the node level might also contribute to pod set. This work aims to identify the main mechanisms responsible for the increase in pod number per node in response to long days; including the dynamics of flowering, pod development, growth and set at the node level. Long days increased pods per node on the main stems, by increasing pods on lateral racemes (usually dominated positions) at some main stem nodes. Long days lengthened the flowering period and thereby increased the number of opened flowers on lateral racemes. The flowering period was prolonged under long days because effective seed filling was delayed on primary racemes (dominant positions). Long days also delayed the development of flowers into pods with filling seeds, delaying the initiation of pod elongation without modifying pod elongation rate. The embryo development matched the external pod length irrespective of the pod's chronological age. These results suggest that long days during post-flowering enhance pod number per node through a relief of the competition between pods of different hierarchy within the node. The photoperiodic effect on the development of dominant pods, delaying their elongation and therefore postponing their active growth, extends flowering and allows pod set at positions that are usually dominated.Facultad de Ciencias Agrarias y Forestale

Genetic and environmental effects on crop development determining adaptation and yield

Slafer, Gustavo Ariel. ICREA - AGROTECNIO - Spain.Kantolic, Adriana Graciela. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.Appendino, María Laura. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.Tranquilli, Gabriela Edith. Instituto Nacional de Tecnología Agropecuaria (INTA). Recursos Naturales. Instituto de Recursos Biológicos. Buenos Aires, Argentina.Miralles, Daniel Julio. Universidad de Buenos Aires. Facultad de Agronomía. Buenos Aires, Argentina.Savin, Roxana. ICREA - AGROTECNIO - Spain.Crop development is a sequence of phenological events controlled by the genetic background and influenced by external factors, which determines changes in the morphology and/or function of organs (Landsberg, 1977). Although development is a continuous process, the ontogeny of a crop is frequently divided into discrete periods, for instance ‘vegetative’, ‘reproductive’ and ‘grain - filling’ phases (Slafer, 2012). Patterns of phenological development largely determine the adaptation of a crop to a certain range of environments. For example, genetic improvement in grain yield of wheat has been associated with shorter time from sowing to anthesis in Mediterranean environments of western Australia (Siddique et al., 1989), whereas no consistent trends in phenology were found where drought is present but not necessarily terminal, including environments of Argentina, Canada and the USA (Slafer and Andrade, 1989, 1993; Slafer et al., 1994a) (Fig. 12.1). Even in agricultural lands of the Mediterranean Basin where wheat has been grown for many centuries, breeding during the last century did not clearly change phenological patterns (Acreche et al., 2008). This chapter focuses on two major morphologically and hysiologically contrasting grain crops: wheat and soybean. For both species, we have an advanced understanding of development and physiology in general. Wheat is a determinate, long-day grass of temperate origin, which is responsive to vernalization. Soybean is a typically indeterminate (but with determinate intermediate variants), short-day grain legume of tropical origin, which is insensitive to vernalization. Comparisons with other species are used to highlight the similarities and differences. The aims of this chapter are to outline the developmental characteristics of grain crops and the links between phenology and yield, to revise the mechanisms of environmental and genetic control of development and to explore the possibilities of improving crop adaptation and yield potential through the fine-tuning of developmental patterns

Necrológica: Ing. Agr. Antonio J. Pascale (1921-2019)

El siguiente texto perteneciente a la señora Decana de la Facultad de Agronomía de la Universidad de Buenos Aires (FAUBA), Marcela E. Gally, y a la señora Vicedecana de dicha institución, Adriana Kantolic, corresponde a la Comunicación de la Facultad con motivo del fallecimiento del Ing. Antonio J. Pascale, fue reproducido en la página web de la ANAV e incorporado en sus Anales con autorización de las autoras.Academia Nacional de Agronomía y Veterinari

Post-flowering photoperiod and radiation interaction in soybean yield determination: Direct and indirect photoperiodic effects

Soybean (Glycine max (L.) Merrill) exposure to long days during the post-flowering phase increases total biomass, nodes, pods and seeds per plant, and also the post-flowering duration, increasing the radiation offer. This work aims to identify the main mechanisms responsible for yield increases in response to long days, separating direct photoperiodic effects on yield determination, from the indirect effect associated with changes in cumulative radiation when the crop cycle is modified by photoperiod. Two field experiments were conducted with an indeterminate soybean cultivar. A factorial combination of two radiation levels (unshaded and shaded), and two or three photoperiod regimes (control, extended 1.5 and 3 h) was imposed from flowering to maturity. Yield tended to be reduced by shade and increased by extended photoperiod mainly through their effects on nodes per m2, and thereby affecting pods and seeds per m2. Photoperiod extension increased node number due to both increased cumulative radiation (indirect effect) and delayed reproductive development (direct effect). As a result, more pods were established per unit of cumulative radiation under extended photoperiod. The results suggest that photoperiod extension enhanced yield radiation use efficiency due to the alleviation of intra-nodal interferences. The direct post-flowering photoperiodic effect on node number and the resultant effects on pod and seed number, provide evidence of direct photoperiodic effects on soybean yield determination.Fil: Nico, Magalí. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Cultivos Industriales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; 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: Kantolic, Adriana Graciela. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Cultivos Industriales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Simulated yield advantages of extending post-flowering development at the expense of a shorter pre-flowering development in soybean

Copyright © 2007 Elsevier B.V. All rights reserved.Field experiments with soybean demonstrated that the extension of photoperiod after flowering increases both the duration of the post-flowering phase and the production of seeds. These results suggest that cultivars with increased duration of the post-flowering phase could be selected to improve soybean yields. The aims of this paper were to: (a) evaluate the ability of the CROPGRO-soybean model to reproduce the experimental relationships between seed number and duration of the critical phase between first and last pod, and (b) assess the putative benefits and trade-offs of variable durations of the critical phase in a south-north transect in the Pampas of Argentina. We varied the genetic coefficients accounting for photothermal requirements and photoperiod sensitivity of soybean A5409-RG (maturity group V), reducing pre-flowering phase while maintaining time to maturity. The model produced sound estimates of crop phenology and reproduced the positive relationship between seed production and the duration of the critical period between first and last pod found in field studies. Linking the model with long-term climate records for six locations between 31 and 37°S, indicated that substantial yield gains could result from increasing the relative duration of post-flowering phases. A hypothetical cultivar with flowering time typical of cultivars of maturity group III and total cycle typical of cultivars of group V, outyielded the traditional cultivar of group V in most cases. For well-watered crops, extension of the critical period had a positive effect in yield in all seasons and locations, whereas for rainfed crops, the extension of the critical period increased yield in 95% of the simulated scenarios. The magnitude of the effect was strongly asymmetric: yield gains were up to 1 Mg ha-1 whereas losses were below 0.2 Mg ha-1. The modelled results in this paper indicate that shortening pre-flowering period without changing the duration of the whole cycle should increase yields in a broad range of latitudes and environmental conditions. © 2007 Elsevier B.V. All rights reserved.Adriana G. Kantolica, Jorge L. Mercau, Gustavo A. Slafer and Víctor O. Sadrashttp://www.elsevier.com/wps/find/journaldescription.cws_home/503308/description#descriptio