Fall Dormancy
Winter-survival is a very complex situation in which dormancy, in itself, plays an important role in at least two ways: 1) vegetative growth stops in dormant varieties to build up root reserves in the fall; while less dormant varieties continue to produce above ground growth. This hardening off and root reserve build up are directly a part of fall dormancy. 2) Varieties that go dormant early are more resistant to breaking dormancy during late winter warm-ups. Other factors genetically linked to fall dormancy include the ability to withstand low temperatures, a deep or buried crown and the ability to compensate for stand loss by the remaining plants' ability to develop larger crowns. The trade off when using a very dormant alfalfa is reduced yield in the third or fourth cutting.

Disease Resistance
Crown diseases and root rots are mildly pathogenic diseases, which can become a problem when a plant ages or is under stress. The most important diseases are bacterial wilt, Phytophthora root rot, Fusarium wilt, Anthracnose, Verticillium wilt, and Aphanomyces root rot. Plant resistance is available for all six diseases. Moderate resistance (MR) to a disease will provide adequate protection to a variety under almost all conditions. In a few instances, where your soil is poorly drained, for example, resistance (R) or high resistance (HR), may be helpful. Beware of varieties with high levels of resistance to all diseases since these levels are unnecessary and usually result in a yield drag. Know what diseases are common in your area and choose varieties with moderate resistance to those.

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