The aim of this investigation was to determine appropriate perennial grasses and their most suitable mixture ratios, which can be grown with alfalfa in binary mixtures. The research was conducted during 2009-2011 in Isparta (37.50 °N, 30.32 °E), located in the Western Mediterranean climate conditions. In the study, alfalfa was planted as a binary mixture with perennial ryegrass (Lolium perenne L.), orchardgrass (Dactylis glomerata L.), meadow fescue (Festuca pratensis Huds.), and smooth bromegrass (Bromus inermis Leyss.) in a randomized block design with three replications. Sowing ratios of alfalfa in the mixtures varied 20, 30, and 40%, and grass species ratios were 80, 70, and 60%. In the study, significant differences were found among the applications regarding hay yield, crude protein content, crude protein yield, NDF, ADF, land equivalent ratio (LER), and grass ratio in the hay (GR). The highest hay yield was obtained from alfalfa + orchardgrass and alfalfa + smooth bromegrass binary mixtures (25.98 and 25.78 t ha-1, respectively). Alfalfa + perennial ryegrass and alfalfa + meadow fescue mixtures gave the highest crude protein contents as 14.93 and 14.80%, respectively. The highest LER values were observed on perennial ryegrass and smooth bromegrass binary mixtures, and the highest grass ratios were determined in orchardgrass and smooth bromegrass mixtures made with alfalfa. Increasing the alfalfa sowing ratio in the mixtures positively affected all quality characteristics such as crude protein, NDF, and ADF. It was concluded that orchardgrass and smooth bromegrass binary mixtures with alfalfa produced high yield and quality hay and that the mixture should contain 40% alfalfa and 60% grass.

La investigación se desarrolló en la Estación Experimental San Antonio (EESA) de Cenicaña ubicada en el corregimiento de San Antonio de los Caballeros (Florida, Valle del Cauca). Se realizaron dos experimentos denominados condición húmeda (con lisímetros para el manejo artificial del nivel freático) y condición semiseca (en campo), utilizando un diseño de bloques completos al azar con tres repeticiones. Se evaluó el aerénquima presente en las raíces fibrosas de 13 variedades de caña de azúcar (Saccharum spp.) a 4, 6 y 8 meses después de la siembra y las variables agronómicas altura de planta, diámetro de tallo, población de tallos, peso de tallos por parcela y producción de sacarosa por parcela al momento de la cosecha. Se encontró una respuesta diferencial entre condiciones a causa de la falta de oxígeno (hipoxia). En condiciones húmedas el aerénquima ocupó 55% del área total de los tejidos en la raíz, sin diferencias estadísticas entre variedades; mientras que en condiciones semisecas sólo ocupó 33%. En ambas condiciones, el aerénquima no mostró asociación con las variables agronómicas evaluadas, no obstante la variedad CC01-1884 presentó el mejor comportamiento agronómico. | The research was developed at the experiment station San Antonio (EESA) of Cenicaña located in the village of San Antonio de los Caballeros (Florida, Cauca Valley). Two experiments were conducted one on semi-dry conditions and another on wet conditions, each one with a design of a randomized complete block with three replications. The aerenchyma observed in the fibrous roots of 13 varieties of sugarcane was evaluated (Saccharum spp) by 4, 6 and 8 months after planting. Agronomic variables as height, diameter, population, stalk weight of total plot, sucrose (% cane) and yield of sucrose per plot were evaluated at harvesting time. It was found that there was a differential response between environments because of the lack of oxygen (hypoxia) in soil. On wet conditions, the aerenchyma occupied 55% of the total area in the root tissues although did not show statistical differences between varieties, whereas the opposite occurred on semi-dry conditions where only occupied 33%. The aerenchyma was not associated with any agronomic traits evaluated. The variety CC 01-1884 had the best agronomic performance in the evaluations.