Evaluación Agronómica de 137 accesiones de Desmodium velutinum, en suelos ácidos

Abstract

Para las condiciones de producción en suelos ácidos en regiones con periodos prolongados de sequía, las alternativas forrajeras son pocas, especialmente leguminosas. Desmodium velutinum, por su adaptabilidad y valor nutricional, puede ser una alternativa para dichas condiciones. Se evaluaron 137 accesiones de D velutinum provenientes de Asia y África del banco de recursos genéticos del Centro Internacional de Agricultura Tropical (CIAT), en la estación experimental CIAT - Santander de Quilichao se plantaron. Una vez germinado, se sembraron en Jiffy pots; seis semanas después, fueron llevadas a campo en la estación experimental del CIAT – Quilichao – Colombia, con un diseño de Bloques Completos al azar, con tres replicaciones. Adicionalmente se sembraron 3 plantas por accesión para observar su comportamiento fenológico. Una vez establecidas, se identificaron tres hábitos de crecimiento, rastrero (17 accesiones), semierecto (66 accesiones) y erecto (54 accesiones), también se avaluó su crecimiento, vigor y presencia de plagas y enfermedades. Se realizaron 2 evaluaciones de producción en época seca y dos en época de máxima precipitación; las 137 accesiones presentaron baja incidencia de plagas y enfermedades, se evaluó la producción de materia seca y su calidad (Proteína cruda y Digestibilidad “in vitro” de la materia seca). Se destacaron como las 20 accesiones más productivas y mejor adaptadas fueron: CIAT 33443, 13953, 23996, 23985,23985, 13218, 33463, 23983, 23276, 23982, 33352, 23081, 33451, 23994, 33396, 23928,33003, 33138, 23920 y 23325 con mas de 200 g y 125 g MS/planta para un rebrote de 8 semanas en lluvias y época seca. Se concluyó que para el ecosistema evaluado, D velutinum tiene potencial como arbusto forrajero de alta calidad nutricional. Es necesario continuar con el proceso de investigación y verificar el comportamiento del arbusto bajo condiciones de pastoreo o corte, así como también su persistencia y hábito de competencia con otro tipo de forrajes.

//Abstract. Under production conditions on acid soils and with prolonged drought conditions, there are just few forage alternatives, especially referring to leguminous species. Therefore, regarding to its adaptation potential and acceptable nutritional value, it was proposed that Desmodium velutinum could be a promising species for these regions where an important part of tropical husbandry takes place. 137 African and Asian accessions of D. velutinum, obtained of from the World Genetic Resources Bank of the International Center of Tropical Agriculture (CIAT) were planted. As they germinated, they were planted in Jiffy pots, and six weeks afterwards they were taken outdoors to the experimental CIAT – Quilichao Station. The statistical design was of random blocks, planting three repetitions with 5 plants each one, keeping 1 m distance between individual rows and 1,5 m between blocks. Additionally, three plants per accession were planted in order to observe their fenological behaviour. Five months after transplanting, the establishing phase was considered finished, there were found three growing patterns: postrate (17 accessions), semierect (66 accessions) and erect (54 accessions). Growth, vigour, and presence of plagues and diseases were evaluated as well. Once the establishing phase was finished, two yield evaluations were carried out for dry and rainfall periods respectively. The 137 accessions presented low plagues and diseases incidence, the total dry matter and its quality (crude protein and dry matter digestibility in vitro). The accessions 33443, 13953, 23996, 23985,23985, 13218, 33463, 23983, 23276, 23982, 33352, 23081, 33451, 23994, 33396, 23928,33003, 33138, 23920 and 23325 showed to be the most productive and the most adapted ones. Producing more than 200 g and 125 g DM/plant for an 8 week regrowth in both seasons respectively. It is possible to conclude that D. velutinum has a potential as high nutrition quality forage for tropical shrub cultures on acid soils and prolonged dry seasons. However, it is necessary to continue with the investigation process and to verify the shrub’s performance under grazing and cutting conditions, as well as its perseverance and competivity in comparison with other forage types.