The Relative Susceptibility of Alfalfas to Wilt and Cold

The final solution of the alfalfa-wilt problem in Nebraska probably lies in the development of resistant sorts that are winterhardy as well as productive. The relative susceptibility to wilt of 40 lots from Turkestan, 10 from France, 6 of Grimm from as many states, and 16 domestic alfalfas are reported on at this time, together with hardiness tests of a few well-known varieties and strains and the more recent introductions from Turkestan and France

Alfalfa Breeding

Interest in the principles of alfalfa breeding has increased greatly with the growing forage consciousness of the country at large and the more specific interest developed through cooperation in the Alfalfa Improvement Conference. As is true of many other forage crops, information on the breeding behavior of alfalfa is meager. During the past few years, however, the genetics and principles of reproduction of this crop have come to be better understood and it is the purpose of this paper to bring together the available information pertaining to the improvement of alfalfa and to add certain suggestions with respect to future possibilities. The new data herein reported were obtained through a cooperative alfalfa breeding program conducted jointly by the Nebraska Agricultural Experiment Station and the Division of Forage Crops and Diseases, Bureau of Plant Industry, U. S. Department of Agriculture. Information will be presented on the amount and manner of natural crossing, the effects of inbreeding and hybridization, and the possible commercial utilization of hybrid vigor in alfalfa

Wilt and Cold Resistance of Self-Fertilized Lines of Alfalfas

The relative reactions to cold and wilt of self-fertilized lines of alfalfa through to the fifth generation are reported. Some of the reasons for undertaking a breeding program are given as well as methods used in the controlled cold and wilt determinations. Preliminary studies showed that reinoculating healthy individuals which had already resisted one wilt infection test served to eliminate additional plants, but the percentage healthy was much higher after the reinoculation than after the first inoculation. The foundation materials from which selections were made consisted of selected plants from a number of old Nebraska fields and a large collection of seed lots assembled by H. L. Westover from many of the alfalfa-growing regions of the world. Some plants from the old fields yielded seed, the seedlings from which had a high degree of resistance to both cold and wilt, whereas others proved to be quite susceptible to either wilt or cold or to both. The latter were usually promptly discarded