Registration of Three Cyst Nematode Resistant Sugarbeet Germplasms: C603, C603‐1, and C604

Dwarf grain pearl millet [Pennisetum glaucum (L.) R. Br.] population NPM-3 (Reg. no. GP-33, P1 574544), released by the Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln in October 1993, is a restorer population for the At cytoplasmic-nuclear male-sterile (cms) system discovered by Hanna (1). The At cms system uses Pennisetum glaucum subsp. monodii cytoplasm, which maintains complete male sterility, with virtually no reversion to male fertility as found with the widely used AI cms system. Male-fertility restorers (Ri) for the At cms system are rare, and none have been made available in agronomically useful dwarf backgrounds. NPM-3 therefore provides a source of agronomically acceptable dwarf plant types from which restorer lines can be derived to produce hybrids utilizing the At cms system. NPM-3 was constituted by random-mating nine dwarf parental lines that had been identified as Ri restorers through testcrosses on male-sterile Tift23DAiE. The male-fertility reactions of the testcrosses were determined in a 1991-1992 nursery and confirmed at Mead, NE, in 1992. The nine Ri restorer lines were chain crossed (i.e., each R* line was crossed with two others) in 1991-1992. The resulting progeny were randommated, maintaining equal maternal representation, in isolation at Mead, in 1992 and 1993 and seeds were bulked in equal quantities to constitute NPM-3. The Rt restorer lines used were derived from crosses made in the grain pearl millet breeding program at the University of Nebraska-Lincoln using parental germplasm from the breeding programs at Fort Hays Branch Experiment Station, Kansas State University; Jamnagar Agricultural University, Gujarat, India; Serere Experimental Station, Soroti, Uganda; and breeding stocks from ICRISAT, Patancheru, AP, India, that contained some West African parentage. In 1992, topcrosses were obtained by including six malesterile lines in an isolation plot of NPM-3. Two pairs of isolines, isogenic for the AI and At cms system, made up four of the six male-sterile lines. The other two lines were unrelated AI and At male steriles. Topcross progenies in 1993, exhibited 93, 96, and 97% average restoration of male fertility for the three AI steriles and 7, 10, and 16% average restoration for the AI steriles. No intermediate or partial male fertility was observed on any plants in A» topcross plots. This contrasts with the AI system where occurrence of partial fertility is frequent, which leads to difficulties in developing both sufficiently sterile seed parents and complete restorers (2). Plants of NPM-3 at Mead, NE, were 80 to 120 cm tall and flowered in 62 to 72 d, averaging 4 d later than KS2068A, which was 95 cm tall. Grain color is gray, and average grain weight is 8 to 12 mg seed". NPM-3 has not been evaluated for reaction to pests and diseases. Small quantities of seed may be obtained from the corresponding author.