The Dynamics of Forage Yield of Different Fall Dormancy Rating Alfalfa Cultivars in a Semiarid Climate

Abstract

Alfalfa (Medicago sativa L.) is one of the most important forage crops to farmers and ranchers in the USA. Plants potential yield quality and its persistence are some of the key traits breeders have targeted to improve crop productivity and adaptation. The objective of this study was to evaluate different sets of alfalfa cultivars under fall and spring plantings for forage yield stability. Field experiments were conducted under sprinkler irrigation at New Mexico State University’s Agricultural Science Center at Farmington to evaluate forage yield of 18, 18, 22, 24, 24, 22, and 22 selected alfalfa cultivars planted in fall 2001, spring 2004, fall 2005, fall 2007, fall 2009, spring 2012, and fall 2014, respectively. The selected alfalfa cultivars were arranged in a randomized complete block design with four replications. The long-term 2001–2018 average annual forage yield of fall planted alfalfa was 21.70 Mg/ha, while the average annual forage yield of the spring planted alfalfa was 19.14 Mg/ha. Forage yield was consistent throughout years with negligible variations. Moderately dormant (FD 5) alfalfa cultivars slightly yielded higher than semidormant (FD 6, 7) cultivars, which showed the lowest forage yield from all the experiments (include the FD grouping means across tests with the LSD). Overall, annual forage yield decreased with fall dormancy rate (FD) at the rate of 0.34 Mg ha−1/FDR. Dormant and moderately dormant alfalfa cultivars should be of first choice in northwestern New Mexico and regions with similar pedoclimatic conditions.