Registration of NC06BGTAG12 and NC06BGTAG13 Powdery Mildew– Resistant Wheat Germplasm

J.P. Murphy and R.A. Navarro, Dep. of Crop Science, North Carolina State Univ., Raleigh, NC 27695; D. Marshall and C. Cowger, USDA-ARS and Dep of Plant Pathology, North Carolina State Univ., Raleigh, NC 27695; S. Leath, Dep of Plant Pathology, North Carolina State Univ., Raleigh, NC 27695; T.S. Cox, The Land Institute, 2440 E. Water Well Road, Salina, KS 67401; J.A. Kolmer, USDA-ARS Cereal Disease Lab. , 1551 Lindig Ave., St. Paul, MN 55108; C.S. Gaines USDA-ARS Soft Wheat Quality Laboratory, 1680 Madison Ave., Wooster, OH 44691. Registration by CSSA. Received 11 Dec. 2006. *Corresponding author (paul_murphy@ncsu.edu). Common winter wheat (Triticum aestivum L.) germplasm lines NC06BGTAG12 (Reg. No. GP-813, PI 642416), and NC06BGTAG13 (Reg. no. GP-814, PI 612417), were developed and released by the North Carolina Agricultural Research Service and the USDA-ARS in 2006. These germplasms were released because of their potential to broaden the genetic base of resistance to powdery mildew [caused by Blumeria graminis (DC.) E.O. Spear f. sp. tritici Em. Marchal] with resistance transferred from the AAGG genome T. timopheevii (Zhuk.) Zhuk. subsp. armeniacum (Jakubz.) van Slageren. Both germplasms have consistently displayed resistance to the powdery mildew fungus in fi eld evaluations in North Carolina from 1999 through 2005. In North Carolina, the following genes are effective for resistance to naturally occurring powdery mildew populations: 1a, 3d, 3e, 3 g, 8, 12, 16, 17, 25, 34, and 35 (unpublished data). The following powdery mildew resistance genes are partially or completely defeated: 2a, 3a, 3b, 3c, 3f, 4a, 4b, 5a, 6, 7, and 20. NC06BGTAG12 is a BC2F7–derived line with the pedigree ‘Saluda’*3/PI 538457. Saluda (PI 480474) is a soft red winter wheat containing Pm3a (Leath and Heun, 1990) and released by Virginia Polytechnic Institute and State University (Starling et al., 1986). PI 538457 is a winter growth–habit accession collected 19 km east of the city of As-Sulaymaniyah, Iraq (35°38 ́ N lat., 045°36 ́ E long., elevation 1050 m). It was deposited in the U.S. National Plant Germplasm System in 1990 by Dr. J. Waines, University of California, Riverside, and was originally collected by Dr. B. L. Johnson, University of California, Riverside, in 1972. NC06BGTAG13 is a BC2F6–derived line with the pedigree ‘Saluda’*3/PI 427442. PI 427442 is a winter growth–habit accession collected 1 km northeast of the town of Salahadin in Arbil province, Iraq (36°24 ́ N lat., 044°12 ́ E long., elevation 1100 m). It was deposited in the U.S. National Plant Germplasm System in 1978 by Dr. B. L. Johnson, University of California, Riverside, who collected the accession in 1972. Pentaploid F1 hybrid (genomes AABGD), BC1F1, and BC2F1 generations were produced in the 1993–1994 and 1994–1995 greenhouse crossing seasons at North Carolina State University. BC2F2 and BC2F3 seeds were planted in single 11.1-m 2 plots containing approximately 1700 seeds during the 1996–1997 and 1997–1998 seasons, respectively, at Clayton, NC. Approximately 100 wellfi lled heads were selected at maturity, threshed in bulk in 1997, and threshed individually in 1998. Field selection using the pedigree breeding method was initiated in the 1998–1999 season at Kinston, NC, with BC2F3:4 lines planted in headrows. Selection during the 1998–1999 and subsequent seasons was primarily for powdery mildew resistance at Feekes growth stages 8 to 10.5, but whenever possible, additional selection for heading date, plant height, and straw strength was conducted with the Saluda phenotype as the benchmark. Natural powdery mildew epidemics occurred annually. NC06BGTAG12 traces to a single BC2F7:8 headrow harvested in 2003. NC06BGTAG13 traces to a single BC2F6:7 headrow harvested in 2002. NC06BGTAG12 had signifi cantly less powdery mildew than Saluda (mean 0.5 vs. 6.5) over 2 yr of advanced-generation testing in NC during 2003–2004 and 2004–2005. Assessments were based on a 0–9 scale refl ecting the extent and position of lesions on the canopy. A score of 0.5 for NC06BGTAG12 indicated lesions were barely detectable in the lower canopy, whereas a score of 6.5 for Saluda indicated lesion coverage of 5% in the middle third of the canopy. NC06BGTAG12 and Saluda were evaluated for agronomic traits at fi ve North Carolina locations in the 2004–2005 season. Mean grain yield and test weight were not signifi cantly different for both lines, but NC06BGTAG12 was signifi cantly different than Saluda in heading date (112 vs. 113 d) and plant height (84 vs. 79 cm). NC06BGTAG12 was one Published in the Journal of Plant Registrations 1: 75–77 (2007). doi: 10.3198/jpr2006.04. 0244crg © Crop Science Society of America 677 S. Segoe Rd., Madison, WI 53711 USA