Metodología simultánea de screening por la efiencia en el uso de bajos niveles de fósforo y por la tolerancia a toxicidad de aluminio y manganeso en suelos adversos para fríjol (Phaseolus vulgaris L.)

A description is given of a simultaneous screening methodology developed to (1) evaluate the efficiency of beans in using low soil P and the response to additional P, (2) evaluate the tolerance to Al and Mn toxicity and bean response to liming, (3) identify efficient/responsive plants, and (4) recommend outstanding materials for breeding. Some introductory notions on the nature of P, Al, and Mn and their interrelationships with the plantsoil system are given along with some aspects on soils in bean-growing regions in L.A. Materials are classified as efficient and inefficient on the basis of yield. The Bean Agronomy Program at the Centro Internacional de Agricultura Tropical carries out screening under field conditions since the plant demands a greater amount of P during the pod filling stage. The application of different levels of lime allows Mn and Al toxicity to be determined; tolerant and susceptible bean materials are planted and compared. Stress level for P are determined by a graphic relating the yields of the different materials used with the different soil P levels; the stress level being the point where the differences among the materials are most marked. An expt. design for simultaneous screening is given including aspects on soil preparation, density, and growth habits. For the phenological evaluation data required include days to germination, germination rate, days to flowering, and days to physiological maturity; for yield analysis the no. of plants harvested, no. of filled pods/plant, no. of pods/plant, and yield in g/m2 are required. In addition to the statistical analysis of data, yield stability of each material is analyzed. Plants can be divided into 4 groups on the basis of 2 parameters, alpha and beta obtained with screening data: efficient with or without a good response; inefficient with or without a good response. Tables and graphics illustrating the results are included. (CIAT)