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RESUMEN Se evaluaron en invernadero en un suelo de Matazul, Meta, Colombia durante 6 semanas, 2 genotipos de Brachiaria (uno mejor adaptado a bajo P, B. decumbens y otro menos adaptado, B. ruziziensis) y 8 progenies del cruzamiento entre ellos ( mejores adaptados: H-7, H-40, H-28, H-58; menos adaptados: H-190, H-94, H-82, H-179). Los genotipos mejor adaptados presentaron mayor biomasa aérea, explicada por mayor área foliar, mayor absorción de P en el tallo y mayor volumen de raíz. Las características morfológicas de las raíces, principalmente longitud, peso seco y contenido de P, permiteron mejor adaptación a bajo P disponible en el suelo. El periodo de evaluación fue suficiente para observar diferencias entre progenies. Two Brachiaria genotypes (Brachiaria decumbens, considered as better adapted and Brachiaria ruziziensis, considered as less adapted) and 8 progenies from the cross of these two (H-7, H-40, H-28 and H-58 more adapted; H-190, H-94, H-82 and H-179 less adapted) were evaluated during 6 weeks to detect differences in shoot and root attributes when grown in an acid soil from Matazul, Meta, Colombia. Results indicated that better adapted genotypes to low P had more shoot biomass, this could be explained by a greater leaf area, more P uptake in the stem and greater root volume. The root attributes, root length, root dry weight and root P content contributed to greater adaptation to low P availability in acid soils. Six weeks of plant growth was not adequate time to distinguish differences in adaptation to low P among the two parents, but it was adequate time to identify superior progenies from the crosses. |
