Nitrogen Remobilization during Grain Filling in Wheat: Genotypic and Environmental Effects

Abstract

purposes (Lhuillier-Soundé lé et al., 1999). Nitrogen remobilization efficiency (NRE) is therefore estimated as In wheat (Triticum aestivum L.), nitrogen remobilization from the the fraction of stored nitrogen at flowering that is not vegetative organs of the crop to the grains has been shown to depend on environmental factors and genotype. We performed, for a set of 10 recovered in the vegetative parts at maturity (Cox et al., winter wheat genotypes, field experiments at six sites over a 2-yr period. 1985a, 1985b Van Sanford and Mackown, 1987). NRE By measuring nitrogen uptake at flowering (NUF from 32-284 kg depends on growing conditions during the grain filling ha Ϫ1 ), the amount of remobilized nitrogen (REMN from 24-228 kg period and genotype. ha Ϫ1 ) and nitrogen remobilization efficiency (NRE from 0.44-0.92) Palta et al. (1994) showed that NRE was high in the we were able to determine the effect of genotype and environment on Mediterranean-like conditions of western Australia, in the relationship between REMN and NUF. Environment and genowhich plants generally suffer from water stress during type had significant effects on nitrogen remobilization and nitrogen the grain-filling period. This increase in NRE may result remobilization efficiency, which mainly depended on treatment (nitroindirectly from limits on nitrogen uptake during the graingen and fungicide) and site. For environments without limiting factor filling period, forcing the plant to make greater use of during the grain-filling period, we found that REMN was not dependent on the genotype and could be estimated by a single two-parameter its stored nitrogen. Cox et al. (1986) showed that higher linear relationship (REMN ϭ 4.13 ϩ NUF ϫ 0.76, r 2 ϭ 0.97). We levels of nitrogen fertilization before flowering lead to analyzed the effect of drought stress before and after flowering, high a decrease in nitrogen remobilization efficiency as the temperature during these periods, nitrogen availability and disease resulting higher level of nitrogen availability just after pressure on REMN by comparing observed and estimated REMN. flowering renders nitrogen remobilization unnecessary. The effect of the environment on the relationship between nitrogen up-Similar results were obtained by Moll et al. (1982) and take at flowering and nitrogen remobilization depended on nitrogen Przulj and Momcilovic (2001) with barley (Hordeum vuluptake during grain-filling period and disease pressure and was also gare L.). Halloran (1981) reported an increase in NRE affected by genotype. Disease-resistant genotypes seemed to be able in conditions unfavorable for nitrogen uptake before to keep remobilization efficiency stable in conditions of strong disease anthesis, linked to drought or high temperature. Foliar pressure, whereas nitrogen remobilization efficiency decreased strongly in susceptible genotypes under the same conditions. diseases, such as brown and yellow rusts (cause by Puccinia spp.), Septoria blotch (caused by Septoria tritici Roberge in Desmaz), and powdery m...

The effect of post-anthesis water supply on grain nitrogen concentration and grain nitrogen Šeld of winter wheat

“…The optimum average temperature during grain growth is generally considered to be less than 20-25°C for wheat, daily maximum temperatures above 30°C were found to reduce the yield of wheat (e.g. Wardlaw and Wrigley 1994, Triboï and Triboï-Blondel 2002, Barbottin et al 2005. The relations between GNC and precipitation, average soil water content and apparent water use during grain growth in experimental years were mostly negative and inconsistent in our experiment.…”

“…The impact of post-anthesis water regime or temperature on grain N concentration and N yield is determined by the effect of the factors on uptake and assimilation of N and also by the influence on the mobilization of previously assimilated N and C from vegetative tissues (Barbottin et al 2005, Egle et al 2008, Ercoli et al 2008). We observed a consistently lower N concentration in straw at harvest as the result of post-anthesis water stress, by 0.09% (N0) and 0.16% (N1), in comparison with irrigated treatment that suggests higher remobilization of N or lower one of C. The effects of water regime on assimilation and remobilization of C and N during grain filling (Barbottin et al 2005 were reflected in C and N yields -GNY reduction due to stress was higher (21%) than average reduction of grain yield (15%) under N0 while under N1 the reduction of GNY (23%) was lower than yield reduction (33%).…”

“…The main tools for regulating N nutrition are specific fertilization systems based chiefly on determined or estimated available supply of soil mineral N (N min ), expected N mineralization and N demand by a crop (e.g. Vaněk et al 2003, Barbottin et al 2005). …”

“…There are distinct genotypical differences in GNC and grain quality parameters in wheat but the uptake and utilization of N are also affected by environmental factors as documented by site and year variability of the parameters (Barbottin et al 2005, Asseng and Milroy 2006, Váňová et al 2006, Estrada-Campuzano et al 2008. Water availability belongs to the strongest factors determining uptake and effectiveness of N use, yield and grain quality (e.g.…”

“…The approach is feasible in semi-arid or Mediterranean climate but not under climate conditions of the Central Europe from where little field data are thus available. Also, the factors as different structure of canopy and root system, soil and plant nutritional and water status before anthesis complicate the interpretation and generalization of observations obtained in different years (Barbottin et al 2005). To overcome the problem, manipulation of soil moisture in field by stationary or mobile sheltering is used Svoboda 2007, Estrada-Campuzano et al 2008).…”