Selenium concentration in wheat (Triticum aestivum) grain as influenced by method, rate, and timing of sodium selenate application

Abstract

Field trials were conducted to identify effective methods of increasing selenium (Se) in wheat (Triticum aestivum) grown on low-Se soils in Canterbury, New Zealand. Various rates (5-20g Se/ha) and methods (soil-applied fertiliser, seed treatment, foliar application at flowering) of applying Se (sodium selenate) were evaluated in autumn-and spring-sown crops on an irrigated site at Wakanui and on a dryland site at Methven. Several Se fertiliser treatments were included to examine the effects of timing of application (Se applied at sowing or growth stage 31) and to determine whether applying other fertilisers (superphosphate, urea) with Se would affectits uptake. Two cultivars were grown in the autumn and spring trials at each location. Grain Se content averaged 0.03 mg/kg in the controls (no Se added), increasing to 0.4-0.5 mg/kg where Se was added at 20g/ha using the most effective application methods-foliar spray and fertiliser at growth stage 31. Fertiliser at sowing was less effective in raising grain Se than fertiliser at growth stage 31, particularly for autumn-sown crops. The results suggested that the plant availability of applied Se can decrease rapidly in the soil and, to be most effective, fertiliser Se should be applied when the crop is beginning to grow rapidly in spring. Grain Se levels for the irrigated site were close to those in the corresponding treatment at the dryland site, even though yield was much greater where irrigation was H06058; used. Application of superphosphate (200kg/ha) or urea (100kg/ha) did not have a large or consistent effect on grain Se. Cultivar effects on grain Se were either small or not significant. For the most effective application methods (fertiliser at growth stage 31; foliar spray), grain Se increased by c. 0.02 mg/kg for an increase in Se rate of 1 g/ha.

Supplemental selenium improves wheat grain yield and quality through alterations in biochemical processes under normal and water deficit conditions

“…However, supplemental Se resulted in much higher grain yield under normal than water deficit conditions. Foliar Se application was observed to be more effective than other Se supply methods and is in agreement with the findings of Curtin et al (2006) who found that foliar application of Se was more effective than soil fertilization in increasing growth and yield of wheat. Literature also confirmed that application of Se increases the growth and yield in rice (Wang et al 2013), lettuce seedlings (Xue et al2001) and soybean (Djanaguiraman, 2004) etc.…”

Possibility of selenium biofortification of winter wheat grain

“…The total Se contained in grain was significantly affected by all the three factors; year, Se form and Se dose (Table 5) Results show that foliar selenite and selenate additions can increase Se contents in mature wheat grains up to 3 and 18 times, compared to selenium non-supplemented crops. As Curtin et al (2006) found, selenium content in wheat grain increased from 0.03 mg/kg in the control samples to 0.45 mg/kg when Se was added as selenate at 20 g/ha by using foliar spray.…”

Selenium Application Timing: Influence in Wheat Grain and Flour Selenium Accumulation Under Mediterranean Conditions

“…Although several other parameters could have affected such lower Se concentration in the grain, a very early application does not seem to be the most convenient. Other authors have reported a better Se accumulation when Se was applied at flowering stage (Curtin et al, 2006) or even at grain filling (Chu et al, 2013). However, these studies were conducted in more humid regions or in irrigated crops.…”

“…Regarding the time of application, many authors (Curtin, Hanson, Lindley, & Butler, 2006;Chu, Yao, Yue, Li, & Zhao, 2013) recommended just one application at stem elongation stage, when the flag leaf ligule/collar is just visible (GS-39 according to the Zadocks scale). That growth stage has been regarded as the most effective one in the later Se accumulation in the grain when several applications moments were evaluated.…”