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N EARLY all improvement in sugar beets has been accomplished through selection. The necessity for controlling the male as well as the female parentage in breeding heterozygous material is an accepted principle in crop improvement.The purpose of these investigations was to find a method by which sugar beets could be successfully selfed for carrying on breeding investigations under Minnesota conditions, without using space isolations. REVIEW OF LITERATUREThrough selection, strains and varieties of sugar beets with high sugar content have been developed. The sugar content of 'the high group selections by various German seed companies has been summarized by Becker-Dillingan (5). 3 In r818 the sugar content was 6.o%. As a result of selection of desirable sized and shaped beets, the sugar content was 9.8% in 1848. By juice polarization the sugar content in 1888 was 13.7% and by pulp polarization selection the sugar content had increased to 21% by 1929-30. But Vilmorin (27), in 1856, reported finding individual beets with a sugar content of 21.0%.Very little progress has been made in breeding sugar beets by the hybridization method. Roemer (r6), in 1915, reported that beets degenerated when inbred. Werner (28) obtained better results by selection. Strains of sugar beets inbred by Dudok Van Heel (8) generally yielded less than open-pollinated commercial seed although not because of degeneration.Inbred strains obtained in Italy by Munerati (12) were less vigorous than normal beets, and crosses gave increased vigor. Darwin (6), in r876, obtained increased vigor by crossing. By selection and inbreeding, Townsend (24) developed lines within three generations which would produce single germ seed balls in 75% of the cases. The "elites" reported by Sunderlin (23) obtained by hybridization of different lines or families gave better yields, as a rule, in comparison with strains obtained by mass selection.When Shaw (19) planted beets 2 miles apart, the highest percentage of seed set was 2.29. Many of the plants were sterile.Grocery bags were used successfully as isolators by Townsend and Rittue (25) in 1904. The seed balls with more than one flower were removed. This left only a small number of seed balls per bag. In this work bags were removed after pollination.