Agronomy and Horticulture Department
Date of this Version
5-1990
Abstract
Ten pairs of A and B (male-sterile and maintainer) inbred lines (N112 to N121, Reg. no. GP 261 to 270, PI 535797 to 535806)of sudangrass [Sorghum bicolor (L.) Moench] [formerly S. sudanense (Piper) Staph] were developed cooperatively by the USDA-ARS and the Nebraska Agricultural Research Division and were released in April 1989. The major objective in the development of these lines was reduction in hydrocyanic acid potential (HCN-p) to facilitate the production of sudangrass hybrids low in HCN-p. While good progress in lowering HCN-p has been made in most lines, some still exceed the level found in 'Piper' sudangrass (Table 1). All lines except N120 and Nl21 are quite closely related, and all A-lines have milo (AI) cytoplasm. N112 to N119 were derived from the progeny of a high-HCN-p B-line obtained from commercial sources crossed to low-HCN-p selections of Piper sudangrass, but N117 to N119 differ from the others in also having a single backcross of the F1 to the B-line parent. N120 and N121 contain germplasm from the two sources listed above, but they also contain germplasm from 'Sweet' sudangrass, from a brown midrib (bmr-6) sorghum line obtained from Purdue University, and from a low HCN-p sudangrass breeding line from the University of Wisconsin. In addition, N120 contains germplasm from an experimental forage sorghum line derived from a cross of 'Early Hegari' x 'Rox', and N121 has some germplasm from 'Nebraska 7035' sudangrass. A brief description of the 10 lines is given in Table 1. All A-lines have had at least six backcrosses to the maintainer line except N113 and N116, which have had only five backcrosses, and all B-lines have been selfed more than six generations. Seed of inbreds N112 to N121 will be maintained and distributed by the Department of Agronomy, University of Nebraska, Lincoln, NE 68583. Germplasm amounts will be provided without cost to each applicant upon written request while supplies last. Recipients of seed are asked to make appropriate recognition of the source of the germplasm if it is used in the development of a new germplasm, parental line, cultivar, or hybrid.