| Phosphorus (P) shortage in soils is a universal limiting factor in agricultural production. P fertilization is one of the most effective ways to increase maize yield. But phosphate rocks is limited , and more P fertilization may caused environment pollution. Large difference exists among maize (Zea mays L.) inbred lines in P uptake and utilization efficiency. To explore P efficient maize germplasm in China, 100 maize inbred lines were evaluated for their P use efficiency on a long term P fertilizer experimental field in two years. The physiological and genetic bases for P efficiency were analyzed. The results showed that:Taking grain yield under low P level and P-deficient symptom as the indicators, some P efficient and inefficient inbred lines were selected under P deficiency (1.6 mg.kg ). They can be used to breed high phosphorus use efficiency hybrid.P-efficient inbred line 154 had higher yield, more ears per m2 and higher ear-set compared with P-inefficient line 153 under low P level. The possible reason was that 154 took up more P than 153 did between stem jointing and the silk stage. Furthermore, the leaf area per plant of 154 was larger than that of 153.The genetic correlations between yield and biomass, number of ears, number of kernels per ear, 100-kernel weight were significant at the 5% or 1% probability levels. Path analysis showed that the direct contribution of biomass and no. of kernels per ear were the largest.The GCAs effect of lines 33, 80 and 85 were positive. Correspondingly, the SCAs effect of hybrids 33×80 and 33×85 were significantly higher than the other crosses under low P level. It is supposed that lines 33, 80 and 85 have potential value in breeding for phosphorus efficient hybrids.
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