Response of rice cultivars to phosphorus supply on an Oxisol

Fageria, N.K.; Morais, O.P.; Baligar, V.C.; Wright, R.J.

Response of rice cultivars to phosphorus supply on an Oxisol

1988

Fageria, N.K. | Morais, O.P. | Baligar, V.C. | Wright, R.J.

Genotypic differences in absorption or utilization of P might be exploited to improve efficiency of fertilizer use or to obtain higher productivity on P-deficient soils, The objective of this study was to evaluate responses by 75 genotypes of upland rice (Oryza sativa L.) to two soil P levels in two field experiments. In the first experiment, soil P levels (Mehlich 1) were 1.5 mg kg⁻¹ and 5 mg kg⁻¹, and in the second experiment, 3 mg kg⁻¹ and 4.7 mg kg⁻¹of soil, respectively. Rice cultivars differed significantly in shoot dry matter production at flowering, grain yield, and plant P status. Based on a grain yield efficiency index, cultivars were classified as P-efficient or P-inefficient. Shoot dry matter was more sensitive to P-deficiency but was not related to grain yield. Phosphorus use efficiency was higher under the low P treatment. Phosphorus uptake was significantly correlated with dry matter, P concentration and P efficiency ratio. Results of this study indicate that genetic differences in P-use efficiency exist among upland rice cultivars and may be exploited in breeding programs.

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