Narrative
BS7 is a yellow dent semi-exotic breeding population derived from CBK [CBK I (PI 329228)] by two cycles of mass selection in Iowa. CBK I was formed at Kitale, Kenya, by the Major Cereal Project in Africa, with USAID, USDA-ARS, the East African Agriculture and Forestry Research Organization, and the Kenya Ministry of Agriculture, cooperating. CBK I included approximately 50% Corn Belt germplasm and approximately 50% exotic material. The Corn Belt sources were: BSSS2 (PI 550444), BSAA (PI 550448), BSBB (PI 550449), Iowa Two-ear Synthetic #1 (PI 550446), Krug Mass Selection, Nebraska Population V, Nebraska Population L, Pioneer 2-Ear Composite, Pioneer hybrids, DeKalb hybrids, Funk hybrids, and PAG hybrids. The exotic material was: French lines (F2, F7, F47, F49, F52, and F431), NBZ (Corn Belt X Brazilian varieties), Nebr. (Eto X early USA), Nebr. (Eto X Gaspe Flint), Alaskan Composite (Gaspe Flint X early USA double crosses), Kenya Katumani Panmix (composite of Central American material), Kenya Katumani IV (probably derived from Salvadureno), Kenya Embu II (composite of 14 Central American varieties), and Kenya Pp Coastal (composite of coastal Kenya material and Central American sources of Puccinia polysora resistance). Synthesis was done in five seasons of random mating at Kitale as follows: A bulk sample of all entries was planted over a 10-day period; pollen from this bulk was carried to a row for each entry of the synthetic. Entry identification of the "female" was maintained for the five cycles of synthesis to insure thorough recombination. A regional diallel grown in the Corn Belt indicated that the yield of CBK is slightly less than those of improved Corn Belt synthetics and that other agronomic characters are satisfactory (Crop Sci. 11:911-914). Seed color is segregating white and yellow.