02225naa a2200277 a 450000100080000000500110000800800410001902400380006010000190009824500770011726000090019452014770020365000160168065000260169665000090172265000210173165000100175265000140176265000160177665000140179265000170180665000150182370000210183870000220185977300660188118589702022-06-06       2010    bl uuuu     u00u1 u    #d7 a10.1080/01904167.2010.4968922DOI1 aFAGERIA, N. K.  aNitrogen use efficiency in upland rice genotypes.h[electronic resource]  c2010  aNitrogen (N) deficiency is one of the most yield-limiting nutrients in upland rice growing regions word wide. A greenhouse experiment was conducted with the objective to evaluate nineteen upland rice (Oryza sativa. L.) genotypes for N use efficiency. The soil used in the experiment was an Oxisol and two N levels used were without N application (low level) and an application of 400 mg N kg-1 of soil (high level). Grain yield and yield components and N uptake parameters were significantly affected by N and genotype treatments. Regression analysis showed that plant height, shoot dry weight, number of panicles per pot, number of grains per panicle, grain harvest index, N uptake in shoot and grain were having significant positive relation with grain yield. Nitrogen concentration of 6.4 g kg-1 in the shoot is established as deficient level and 9.5 g kg-1 as sufficient level at harvest. Agronomic efficiency of N (grain yield/unit of N applied) and N utilization efficiency (physiological efficiency X apparent recovery efficiency) were significantly different among genotypes. These two N use efficiencies were having significant quadratic relationship with grain yield. Soil pH, exchangeable soil Ca and base saturation were having significantly positive association with grain yield. However, soil extractable phosphorus (P), potassium (K), hydrogen (H+), aluminum (Al) and cation exchange capacity were having significantly negative association with grain yield.  aGrain yield  aNutrient deficiencies  aRice  aYield components  aArroz  aGenótipo  aNitrogênio  aNutriente  aOryza sativa  aProdução1 aMORAIS, O. P. de1 aSANTOS, A. B. dos  tJournal of Plant Nutritiongv. 33, n. 11, p. 1696-1711, 2010.