Rendimiento de forraje y sus componentes en variedades de alfalfa en el altiplano de México

Alfalfa ( Medicago sativa L.) is the cultivated legume that is mostly used in milk and meat production in Mexico, due to its high yield and nutritional value. The objective of this study was to evaluate the yield of forage and its components, in five alfalfa varieties, with seasonally defined cutting intervals. The Aragon, Valenciana, Chipilo, Milenia and Oaxaca varieties were randomly distributed in 20 experimental, 12 x 9 m plots, according to a randomized complete block design with four repeats. The evaluations included forage yield in a dry base, stem weight, stem population m -2 , plant population m -2 , leaf:stem ratio, botanical and morphological composition.  The highest and lowest yields were obtained in the Milenia and Aragon varieties, with 20,643 and 14,488 kg DM ha -1 . The weight per stem was better in Aragon, Chipilo and Milenia, and lower in Valenciana and Oaxaca. Aragon had the greatest stem density, with 634 stems m -2 ,and Oaxaca, with 512 stems m -2 , had the lowest density. The highest leaf:stem ratio was found in Aragon, with 1.31, and the lowest was found in Oaxaca, with 1.13. In fall and winter, a larger amount of leaves was obtained, independently of the variety, and in summer, there was an increase in all weed varieties. Seasonality was related to yield, with a greater production in spring and summer, due to temperature, and to a greater stem weight. The variety with greatest dry matter yield was Milenia, and Aragon had the lowest yield.