Adaptation of Beans (Phaseolus Vulgaris L.) to Low Phosphorus Availability Jonathan P
Adaptation of Beans (Phaseolus vulgaris L.) to Low Phosphorus Availability Jonathan P. Lynch1 Department of Horticulture, The Pennsylvania State University, University Park, PA 16802 Stephen E. Beebe Bean Program, International Center for Tropical Agriculture, Apartado Aéveo 6713, Cali, Colombia Phosphorus availability in native soils is seldom adequate for has been carried out in Colombia (Thung, 1990; Youngdahl, 1990), optimal plant growth. Of the macronutrients, K, Ca, Mg, and S are not Brazil [Salinas, 1978; International Center for Tropical Agriculture uncommon in the earth’s crust and in fresh water (Epstein, 1972); N is (CIAT), unpublished data], Costa Rica (Corella, unpublished data), abundant in the atmosphere and is present in most soil solutions in and Nicaragua (Tapia, 1987). In at least one case, recommendations millimolar concentrations. In contrast, P is present in soil solution and for P applications were tailored cultivar by cultivar, from 0 to 42 kg P/ fresh water in only micromolar concentrations (Rendig and Taylor, ha, depending on the P requirements of the specific genotype. The 1989), in large part because P is commonly bound to many soil Brazilian cultivar Carioca is broadly adapted to low-P conditions, and constituents that make it unavailable or only sparingly available to is extremely responsive to added P (Thung, 1990). These traits plants (Sample et al., 1980). An additional problem is that the P cycle undoubtedly contribute to the fact that ‘Carioca’ is the most widely in most terrestrial ecosystems is open-ended and tends toward deple- grown cultivar in Brazil (Janssen et al., 1992). In Rwanda, a climbing tion, unlike the N cycle, in which atmospheric pools provide continual bean from Mexico, G2333, has gained great popularity among small inputs to soil pools (Stevenson, 1986).
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