| 0 | PI 608773 | BS7 | Zea mays L. subsp. mays | Iowa, United States | NC7 |  | | 1998 | DEVELOPED | | | | | | Breeding material | 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. | 1002682 | PI 608773 |
| 1 | PI 608771 | BSL(S)C4 | Zea mays L. subsp. mays | Iowa, United States | NC7 |  | | 1992 | DEVELOPED | | | | | | Breeding material | BSL(S)C4 is a yellow dent breeding population developed from the open-pollinated Lancaster Surecrop variety by four cycles of recurrent S1 selection for stalk-rot resistance. Lancaster Surecrop (PI 213697) was obtained from the North Central Regional Plant Introduction Station, Ames, Iowa, in 1955. S1 progenies were grown with three replications at Ames, Iowa, each cycle and artificially inoculated with spores of Diplodia zeae (Schw.) Lev. The selection intensity was 12, 6, 12, and 11%, respectively, for the four cycles of selection. BSL(S)C0, Cl, C2, and C3 were evaluated as populations per se and in testcross with two unrelated single-cross testers for several agronomic characters (Iowa State J. Sci. 43 (3):229-237; Iowa State J. Sci. 43(3):239-251). BSL(S)C3 was slightly taller, 3 days later in silk emergence, more resistant to natural stalk rot and field stalk lodging, and similar for grain yield (but higher in testcross yields) than Lancaster Surecrop. BSL(S)C4, the next cycle of selection, is resistant to D. zeae as a variety and should be a superior source of inbred lines with satisfactory resistance to stalk rot and field stalk breakage. | 1082054 | PI 608771 |
| 2 | PI 608772 | BS5 | Zea mays L. subsp. mays | Iowa, United States | NC7 |  | | 1992 | DEVELOPED | | | | | | Breeding material | BS5 is an early yellow dent synthetic that was developed by intermating twenty-three inbred lines: A265, A548, A554, A575, A619, B8, Ch9, F2, F7, F47, F49, F52, F431, Mt42, ND203, WD, WH, WJ, W9, W59M, W97A, W75, and W153R. This early synthetic was formed in the following manner: single crosses among lines, double crosses among single crosses; all possible double-double crosses among double crosses; and randomly mating the composite for two generations. The purpose for developing this synthetic was to provide an early population for recurrent selection and line development. No selection has been practiced in the synthetic, and the relative yield potential of the synthetic is unknown. BS5 is an early synthetic for central Iowa, requiring approximately 70 days from planting to silking. | 1082046 | PI 608772 |
| 3 | PI 608821 | BS8 | Zea mays L. subsp. mays | Iowa, United States | NC7 |  | | 1970 | DEVELOPED | | | | | | Breeding material | BS8 is a semi-exotic synthetic derived from Kenya SK (CBK II) by two cycles of mass selection in Iowa. SK (PI 347266) was formed at Kitale, Kenya, by the Major Cereals Project in Africa, with USAID, USDA-ARS, the East African Agriculture and Forestry Research Organization, and the Kenya Ministry of Agriculture, cooperating. SK includes germplasm from the southern USA and the Corn Belt and exotic material from Central and South America, Africa and Europe. The sources were: N. Carolina Jarvis and Indian Chief, DeKalb southern hybrids, Funk Deep South Syn., Funk Tropical Syn., Coker hybrids, Pioneer southern hybrids, Pioneer West Indies Synthetic (Iowa), Pioneer West Indies Synthetic (Tenn.), Pioneer Caribbean Composite, Pioneer Jamaica Synthetic, Tuxpeno X Lancaster, Yugoslav hybrids, Diacol V254, Diacol V540C, Nigeria Late Composite, Nigeria Composite C, Zambia SR52, Zambia Kalahari Syn., Ecuador 573, Puerto Rico GPO2 and GPO6, Cuba 40-Hawaii 5, Cometico, Israel hybrids, USA X Camalia, Kenya Embu I (composite of Central America and USA Germplasm), Nigeria Bulk 2 (NS-1, Tsolo, Diacol V103, Miss.6002, Miss.6004, Metro, EAAFRO 270, EAAFRO 237, Br.155, and Metro). 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. SK was evaluated in a regional diallel grown in seven southern locations (Crop Sci. 11:911-914). Seed color is segregating white and yellow. | 1002687 | PI 608821 |