130 research outputs found
Coarse and fine regulation of wheat yield components in response to genotype and environment
No full textAbstract not availableGustavo A. Slafer, Roxana Savin, Victor O. Sadra
Leaf photosynthesis during grain filling under mediterranean environments: are barley or traditional wheat more efficient than modern wheats?
No full textBarley is one of the most popular crops in dryland agricultural systems of Mediterranean areas, where it is assumed that barley, or traditional wheat cultivars, performs better than modern wheat under low-yielding conditions. It was tested whether variations in net leaf photosynthetic rate (PN) during grain filling provide any basis for the potential better performance of barley and traditional wheat compared to modern wheats in Mediterranean areas. Two groups of field experiments were conducted in Agramunt (NE Spain) during 2005/06 (06) and 2006/07 (07) growing seasons combining low and high nitrogen (N) availabilities under rain-fed and irrigated conditions. Cultivars used in the first group of experiments were a traditional (Anza) and a modern (Soissons) wheat, whilst in a second group of experiments, a wheat (Soissons) and a barley (Sunrise) modern cultivars were used. Both wheat cultivars showed a similar PN during grain filling but higher than that of the modern barley cultivar. Differences between species in PN were maximized under high-yielding conditions. There were no differences between cultivars in instantaneous water-use efficiency. The barley cultivar showed a higher specific leaf area, but lower N content per unit of leaf area, than wheat. Photosynthetic nitrogen-use efficiency was similar between the traditional and the modern cultivar but lower than barley. Decreases in PN after anthesis were not exactly observable in SPAD measurements. In conclusion, we found no consistent differences between cultivars in terms of post-anthesis photosynthetic activity to support the assumption of better performance under Mediterranean farm conditions of traditional wheat or barley against modern wheat.Fil: Abeledo, Leonor Gabriela. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Savin, Roxana. Universidad de Lleida; España. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Slafer, Gustavo Ariel. Institució Catalana de Recerca i Estudis Avancats; España. Universidad de Lleida; España. 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
No full textCopyright © 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
Genetic and environmental effects on crop development determining adaptation and yield
No full textSlafer, 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
Trends of nitrogen use of oat cultivars from 1902 to 2002 in Finland
No full textPlant breeding has improved grain yields of oats in northern growing conditions (Rekunen 1988, Slafer &Peltonen-Sainio 2001).One main contributor to increased yields is harvest index (HI). Cultivars have higher HI and reduced plant height compared to landraces or old cultivars (Peltonen-Sainio 1991). The response of oats to nitrogen fertilizers is also improved (Peltonen-Sainio 1993). The aim of this study was to identify the changes in nitrogen economy caused by plant breeding in northern growing conditions. In growing season 2003, eighteen oat cultivars (released between 1902 and 2002) were studied in MTT, Jokioinen. Experiment was treated with 70 kg N ha-1 and soil N content was measured on spring and autumn. Plant samples were collected at maturity and the plants were divided into main shoots and tillers and further to panicles and vegetative mass. The dry weight was measured and samples were grind for N analyses. Nitrogen harvest index (NHI), N utilization efficiency (UTE), N uptake and N use efficiency were calculated from the dry weights and N contents of the plants. On the basis of one year results, plant breeding has only changed the N utilization efficiency, not so much N uptake. There were no significant difference between the cultivars in N use efficiency or in N content of the plant (g N m- 2). Cultivars did not differ in N uptake either. Instead UTE on new cultivars was 38.4 g g N-1 while it was 35.1 g g N-1 on old cultivars. There was positive correlation between UTE and NHI and also between NHI and HI. The one year results imply that grain yield is more breed quality than N content or N uptake. Peltonen-Sainio, P. 1991. Journal of Agronomy & Crop Science 166: 90-95; Peltonen-Sainio, P. 1993. Journal of Agronomy & Crop Science 171: 268- 273; Rekunen, M. 1988. Journal of Agricultural Science in Finland 60: 307- 321; Slafer, G. & Peltonen-Sainio, P. 2001. Agricultural and Food Science in Finland 10: 121-131.vokMyynti MTT tietopalvelut. Yksikön huom.: KV
Radiation use efficiency of modern and old oat cultivars in Finland
No full textFinnish plant breeding of oats has focused on improving stability as well as productivity in northern growing conditions. Breeding for short stature and early maturing oat lines has increased harvest index (HI) close to 55% (Peltonen- Sainio 1991) and grain yields by 0.3% year-1 (Slafer & Peltonen Sainio 2001). However to further increase grain yield, the biomass production should still be augment (Peltonen-Sainio 1991). Since radiation use efficiency (RUE) and accumulated intercepted radiation (.Ri) are major elements of crop growth and biomass production (Gallagher and Biscoe 1978), the aim of this study was to identify how they have changed by plant breeding in northern growing conditions. On growing seasons 2002 and 2003 the crop radiation interception was calculated from spot measurements of incident and transmitted radiation. Above ground dry matter was determined at particular stages of development of the cultivars and green leaf area was measured at the same time. The plots were fertilised with 90 kg and 0 kg N ha-1. Irrigation was practised in 2002. RUE, .Ri, light extinction coefficient k, green leaf area and biomass accumulation were calculated for each cultivar for pre-anthesis. There was no significant difference between the cultivars on biomass accumulation, radiation accumulation or on RUE (P = 0.08) on vegetative period. More total biomass seemed to accumulate on old cultivar even though the difference was not significant. There were also no significant difference between the cultivars on light interception or on light extinction coefficient. Only the 0 kg N ha-1 fertilizer rate resulted in some reduction in light interception during the year 2002. The RUE values at pre-anthesis were higher during the growing season 2002 than on 2003, (means were 2.02 g MJ-1 and 1.78 g MJ-1). The fertilizer rate of 90 kg N ha-1 resulted in higher RUE values than 0 kg N ha-1 on both years. Gallagher, J. and Biscoe, P. 1978. Journal of Agricultural Science 91: 47-60; Peltonen-Sainio, P. 1991. Journal of Agronomy & Crop Science 166: 90-95; Slafer, G. & Peltonen-Sainio, P. 2001. Agricultural and Food Science in Finland 10: 121-131.vokMyynti MTT tietopalvelut. Yksikön huom.: KV
Wheat pre-Anthesis development as affected by photoperiod sensitivity genes (Ppd-1) under contrasting photoperiods
No full textFine tuning wheat phenology is of paramount importance for adaptation. A better understanding of how genetic constitution modulates the developmental responses during pre-Anthesis phases would help to maintain or even increase yield potential as temperature increases due to climate change. The photoperiod-sensitive cultivar Paragon, and four near isogenic lines with different combinations of insensitivity alleles (Ppd-A1a, Ppd-B1a, Ppd-D1a or their triple stack) were evaluated under short (12 h) and long (16 h) photoperiods. Insensitivity alleles decreased time to anthesis and duration of the three pre-Anthesis phases (vegetative, early reproductive and late reproductive), following the Ppd-D1a > Ppd-A1a > Ppd-B1a ranking of strength. Stacking them intensified the insensitivity, but had no additive effect over that of Ppd-D1a. The late reproductive phase was the most responsive, even exhibiting a qualitative response. Leaf plastochron was not affected but spikelet plastochron increased according to Ppd-1a ranking of strength. Earlier anthesis resulted from less leaves differentiated and a fine tuning effect of accelerated rate of leaf appearance. None of the alleles affected development exclusively during any particular pre-Anthesis phase, which would be ideal for tailoring time to anthesis with specific partitioning of developmental time into particular phases. Other allelic variants should be further tested to this purpose.Fil: Pérez Gianmarco, Thomas Ignacio. Universidad de Lleida; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires; ArgentinaFil: Slafer, Gustavo Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Institució Catalana de Recerca i Estudis Avancats; España. Universidad de Lleida; EspañaFil: González, Fernanda Gabriela. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Norte. Estación Experimental Agropecuaria Pergamino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires; Argentin
Wheat floret survival as related to pre-anthesis spike growth
No full textFurther improvements to wheat yield potential will be essential to meet future food demand. As yield is related to the number of fertile florets and grains, an understanding of the basis of their generation is instrumental to raising yield. Based on (i) a strong positive association between the number of fertile florets or grains and spike dry weight at anthesis; and (ii) the finding that floret death occurs when spikes grow at maximum rate, it was always assumed that floret survival depends on the growth of the spike. However, this assumption was recently questioned, suggesting that assimilates diverted to the spike do not determine the number of florets and grains and that the onset of floret death may instead be a developmental process that is not associated with spike growth. In this study, the relationships between the fate of floret primordia and spike growth from six independent experiments that included different growing conditions (greenhouse/field experiments, growing seasons, photoperiod/shading treatments during the floret primordia phase) and diverse cultivar types (winter/spring, semi-dwarf/standard-height, photoperiod sensitive/insensitive) were re-analysed together. Onset of floret death was associated with the beginning of spike growth at the maximum rate in c. 80% of the cases analysed; and the rate of floret death (the main determinant of floret survival) showed a negative quantitative relationship with spike weight at anthesis. As floret death and survival were shown to be linked to pre-anthesis spike growth, the strategy of focusing on traits associated with pre-anthesis spike growth when breeding to increase wheat yield potential further is valuable.Fil: González, Fernanda Gabriela. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Norte. Estación Experimental Agropecuaria Pergamino; 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; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Norte. Estación Experimental Agropecuaria Pergamino; ArgentinaFil: Slafer, Gustavo Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Institució Catalana de Recerca i Estudis Avancats; España. Universidad de Lleida; Españ
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