FOLIAR APPLICATION OF 15N-UREA AND ALLOCATION INTO GLUTEN OF DIFFERENT WHEAT CULTIVARS
2020
Klaus-P. Gotz | Klaus D. Wutzke
Assessment of fertilizer nitrogen uptake into wheat grains and proteins is an important issue for selec-tion of N efficient cultivars. The 15N dilution technique is the most reliable way to follow the flow and fate of N for studies examining the path of N into wheat grains. Studies on wheat cultivar responses to late-season urea application in terms of grain quality traits are scarce. To assess the effect of a late N fertilization, known as quality effective, classified German spring wheat cultivars and two cultivars from the Mediterranean territory were examined in a field experiment in northeast Germany. At flag leaf sheath opening, 20 kg N ha-1 were given as foliar application (urea solution; to which 15N labelled urea was added; 10 atom-% 15N enrichment; correspond to 8.3 mg 15N m-2). At maturity, 35 days after 15N labelling, the gluten protein content, the 15N-recovery, and the 15N content of grains and of gluten were determined. Forty (Gonen) to 58% (Picolo) of the applied 15N was recovered in the grains per m2, which means an effective translocation of the late applied N, however no significant differences between the cultivars occurred. The 15N content in grains was markedly higher in Thasos, Melissos, Taifun, Picolo, Triso (mean 14.7 μg 15N g-1 dry matter-1) compared to Tybalt, Monsun, Golia and Gonen (mean 11.6 μg 15N g-1 dry matter-1). The 15N content of the gluten fraction was not influenced by cultivar and lies in the range between 14.7 and 19.4 μg 15N g-1 dry matter-1. The applied 15N is after 35 days at harvest to 16% involved in the gluten synthesis, and this independently of the spring wheat cultivars and classification.
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