Pastos y Forrajes (Jun 2012)
Comportamiento de la simbiosis leguminosa-rizobio en Centrosema plumieri inoculada con Bradyrhizobium sp. Ensayo de campo Performance of the legume-rhizobium symbiosis in Centrosema plumieri inoculated with Bradyrhizobium sp. Field essay
Abstract
Se efectuó un experimento de campo, sin riego, en la Estación Experimental de Pastos y Forrajes de Sancti Spíritus, Cuba, durante el periodo de noviembre de 2001 a abril de 2002. El objetivo fue evaluar el comportamiento simbiótico de Centrosema plumieri, inoculada con cepas de Bradyrhizobium sp., previamente aisladas de leguminosas forrajeras procedentes de ecosistemas ganaderos de Cuba. El diseño experimental fue de bloques al azar; se utilizaron 11 tratamientos inoculados con cepas nativas, un testigo inoculado con la cepa de referencia 5030 (Bradyrhizobium sp.) y un control no inoculado, con tres réplicas. Se aplicó un análisis de varianza (ANOVA), así como de correlación y regresión. Los valores de los tratamientos inoculados fueron estadísticamente iguales a los del control absoluto, en cuanto al peso seco aéreo (PSA) y el rendimiento de N (RN), excepto el inoculado con la cepa HA2 en RN. En general, se demostró una débil efectividad de la inoculación. No obstante, en el índice de nodulación (IN) sobresalieron JH2 y HA2, con valores estadísticamente superiores (pA field trial, without irrigation, was conducted at the Sancti Spiritus Experimental Station of Pastures and Forages, Cuba, from November, 2001, to April, 2002. The objective was to evaluate the symbiotic performance of Centrosema plumieri, inoculated with Bradyrhizobium sp. strains, previously isolated from forage legumes of Cuban livestock production ecosystems. The experimental design consisted in randomized blocks; 11 treatments inoculated with native strains, a control inoculated with the reference strain 5030 (Bradyrhizobium sp.) and a non-inoculated control were used, with three replications. A variance analysis (ANOVA), as well as correlation and regression analyses, were applied. The values of the inoculated treatments were statistically equal to those of the absolute control, regarding aerial dry weight (ADW) and N yield (NY), except the one inoculated with the strain HA2 in NY. In general, a weak activity of inoculation was shown. Nevertheless, in the nodulation rate (NR) JH2 and HA2 stood out, with values statistically higher (p<0,05) than the others. The degree of dependence of NY and ADW was weak in the inoculated treatments with regards to NR, although it was strong in NY with regards to ADW. It is concluded that the native strains inoculated in C. plumieri, with the exception of HA2 in NY, as well as JH2 and HA3 in NR, did not exert a highly positive effect on this plant. These results should be evaluated for the continuation of studies related to the legume-rhyzobium symbiosis.
