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This article in CS

  1. Vol. 36 No. 4, p. 936-941
    Received: July 6, 1995

    * Corresponding author(s): jlynch@psupen.psu.edu


Utilization of Phosphorus Substrates by Contrasting Common Bean Genotypes

  1. Xiaolong Yan,
  2. Jonathan P. Lynch  and
  3. Stephen E. Beebe
  1. L ab. of Plant Nutrition, South China Agric. Univ., Guangzhou 510642, China
    D ep. of Horticulture, The Pennsylvania State Univ., University Park, PA 16802
    B ean Program, International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia



Phosphorus deficiency limits common bean (Phaseolus vulgaris L.) production in tropical soils, where P may be bound to recalcitrant organic matter, or with aluminum or iron oxides. In a previous study, we showed that P-efficient genotypes perform well in contrasting soils, suggesting that interactions with specific soil constituents did not account for genetic variation. To confirm this finding, a study was done to determine if contrasting bean genotypes differ in their ability to recover P from different P compounds. Six genotypes were planted in pots of silica sand in which P was supplied at four levels as KH2PO4, CaHPO4, inositol hexaphosphoric acid (IP6), FePO4, or AIPO4. Most results could be explained as a function of relative aqueous solubilities of the P sources. KH2PO4 gave the greatest uptake and growth and FePO4 the least. No differences were observed in the ability of the six genotypes to acquire P from the Al, Fe, or IP6 sources. Andean genotypes, especially the Peruvian landrace G19833, extracted more P from CaHPO4 than Mesoamerican genotypes. G19833 was capable of acidifying the rhizosphere more than other genotypes. We conclude that (i) differential ability to mobilize P from Fe, Al, and organic ligands does not account for genetic variation in P efficiency, and (ii) Andean germplasm has superior ability to mobilize P from Ca sources, which may be useful in utilizing phosphate rock fertilizers.

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