Yan, X.; Lynch, J.P.; Beebe, S.E.


Crop Science, Volume 35, Issue 4, p.1086-1093 (1995)

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Phosphorus deficiency is a primary limitation to bean ( Phaseolus vulgaris ) production in the tropics. Bean genotypes differ in their P efficiency, defined as growth and yield in low P soil. Traits conferring P efficiency may be useful only in specific soil types, or may represent more general adaptations to low P availability. This information is essential in selecting and breeding more P efficient bean germplasm. Sixteen contrasting genotypes were grown in pots of Andosol, Ultisol and Oxisol soil at three levels of applied P in the tropics. At 35 days after planting, shoot growth, root growth, P accumulation and symbiotic status were evaluated. Genotypes differed significantly in P efficiency. The relative ranking of genotypes for shoot biomass, root biomass, root length, or P accumulation under all P levels was not affected by soil type and was not related to the degree of rhizobial or mycorrhizal infection. Large-seeded Andean genotypes were superior to small-seeded Mesoamerican genotypes, especially under low P. Small-seeded Mesoamerican genotypes were more responsive to added P. It is concluded that (i) large genetic variation for P efficiency exists in tropical bean germplasm, (ii) this variation reflects a general adaptation to low P availability rather than an interaction with specific soil types or soil microbes, (iii) large-seeded germplasm appears to have superior P efficiency under low P availability, and (iv) Mesoamerican genotypes are more responsive to added P.