Genetic improvement of aerial alfalfa biomass and its components: half-sib family selection

In this study, it was evaluated the genetic variation in aerial biomass (BM) or dry matter yield (DMY) and its components in 400 alfalfa half-sib families (HSF), derived from direct (DC, San Miguel x Oaxaca) and reciprocal crosses (RC, Oaxaca x San Miguel), and the original varieties (SM, San Miguel; O, Oaxaca). The experiment was performed in pots under outdoor conditions in Montecillo, Texcoco, Estado de Mexico, Mexico. Complete plants were cut at a 5 cm height, every five weeks in the fall-winter of 2014-2015, and every four weeks in the spring-summer of 2015. The DMY, AGR (absolute growth rate), RUE (radiation use efficiency), NT (number of tillers per plant), and PH (plant height) were 32, 31, 32, 6, and 36 % higher in DC. The DMY, AGR, RUE, and PH were 30, 28, 30, and 34 % higher in RC than the mean of SM and O varieties. The selection allowed the identification of 13 and 17 % of HSF outstanding in DMY and its components in DC and RC. The DMY of the outstanding HSF of DC was 11% higher than the DMY of the outstanding HSF of RC, indicating maternal genetic effects.