Registration of UCRBW98‐1 and UCRBW98‐2 Wheat Germplasms with Leaf Rust and Greenbug Resistance Genes

Published August 21, 2014 CROP SCIENCE, VOL. 40. MARCH-APRIL 2000 Registration of UCRBW98-1 and UCRBW98-2 Wheat Germplasms with Leaf Rust and Greenbug Resistance Genes Two wheat (Triticum aestivum L.) germplasms with intersti- tial translocations (UCRBW98-1, Reg. no. GP-594. PI 603918 and UCRBW98-2, Reg. no. GP-595, PI 603919) were devel- oped to transfer genes for resistance to leaf rust (caused by Puccinia triticina Eriks.) and greenbug (Schizaphis graminum Rondani) from chromosome 7S of Triticum speltoides (Tausch) Gren. The origin of chromosome 7S is not clear (1, 3) but likely it originated from a population obtained by irradiation of a hybrid €115092/7. s/7e/to«fes//'Fletcher'/3/ 5*'Centurk' with fast neutrons (7). Translocations of segments of 7S to 7A were produced by recombination induced by the phlb mutation (3). Sears' (4) strategy was followed to reduce the length of the alien chromosome segments. All manipula- tions were performed in hard white spring cultivar Pavon F76; a total of eight backcrosses were made to Pavon and the likely pedigree of both lines is CI15092/7. speltoides//F\etcher/3l 5*Centurk/4/4*Pavon F76/5/Pavon phlb/6/3*Pavon F76 where Pavon phlb is Chinese Spring phlb /8*Pavon MSB. Plants homozygous for the interstitial translocations were se- lected by C-banding. Translocations were characterized using molecular markers (1). The short arm translocation line Pavon T7AS-7S#1S- 7AS7AL designated UCRBW98-1 (PI 603918) carries resis- tance gene Lr47 for leaf rust. This gene confers resistance to a wide spectrum of leaf rust races including nine that are virulent on resistance genes Lrl and LrlO present in Pavon F76 (PRT codes: TBT-10. NBB-10, MBR-10, LCG-10, SDJ- 10, MBG-10, NDB-10, MCG-10, and TDD-10; (2). The 7. speltoides segment present in this translocation is located 2 to 10 cM from the centromere and is 20 to 30 cM long (1). The long arm translocation line T7AS7AL-7S#1 L-7AL designated UCRBW98-2 (PI 603919) carries gene Gb5 (6) that confers resistance to greenbug biotypes C, E, I. and K but not to biotypes B, F, G, H. This gene is located on an interstitial 7. speltoides chromosome segment that is 40 to 50 cM long and is located 18 to 22 cM from the centromere of chromosome 7AL (1). The interstitial segments of 7. spelloides chromosome pres- ent in both translocation lines do not recombine with wheat chromosome 7A in the presence of the wild-type Phi locus and will be transmitted as single loci. Consequently, Lr47 is completely linked to RFLP markers Xwg834, Xcdo475, XmwgJIO, Xabcl52, XabclSS, XBrz, and Xabc465, and Gb5 is completely linked to RFLP markers Xpsrl29, Xpsr547, Xwg380, Xabg461, Xwg420, Xmwg2062, and Xpsr680. Molec- ular markers can also be used to transfer leaf rust resistance gene LrlO present in chromosome 1A of the recurrent parent Pavon (5). Though these translocation lines may be useful in breeding, no information is currently available on putative yield penalt- ies associated with other genes present in the interstitial seg- ments of 7. speltoides chromosome 7S. Small quantities of seed of these lines can be obtained for research and breeding purposes from the corresponding author. A.J. LUKASZEWSKI.* D.R. PORTER, E.F. ANTONEI.LI, AND J. DUBCOVSKY (8) Registration of 10 Wheat Germplasms Resistant to Septoria tritici Leaf Blotch Ten spring wheat (Triticum aestivum L.) germplasms CIGM90.248, CIGM90.250.1, CIGM90.250.2, CIGM90.358 CIGM 90.412, CIGM90.483, CIGM91.153, CIGM91.191 CIGM91.248, CIGM92.337, (Table 1) (Reg. no. GP-562 tc GP-571; PI 610750 to PI 610759) were developed by the Wide Crosses program of the International Maize and Wheat Im- provement Center (CIMMYT), El Batan, Mexico for im- proved resistance to Septoria leaf blotch (caused by Septorio tritici Roberge ex Desmaz). This fungal disease limits wheal production in high rainfall areas across 10.4 million hectares globally (1). The lines were derived from 5. tritici resistani synthetic hexaploids (SH) (7. turgidum/Aegilops tauschii) thai were crossed with the S. tritici susceptible wheat cultivars Sen M82, Yaco, Borlaug M95, Opata M85, Kauz, Papago M86 and the moderately resistant cultivar Bagula. Segregating generations of the crosses were advanced by the pedigree breeding method. The mean agronomic performance and disease scoring data of 10 germplasm lines resistant tc Septoria leaf blotch over three years of field tests is presented in Table 1. The 10 germplasms are F 5 to Ft, derived selections Five Mexican isolates that were virulent on both 7. turgidum and 7. aestivum germplasms were mixed to inoculate popula- tions twice over three weeks during the tillering stage of the lines and cultivar checks with ULVA (ultra low volume) appli- cations. 'Bobwhite' (resistant check), Kauz and Seri M82 (sus- ceptible checks) were included in the 3-yr Septoria leaf blotch evaluations. Ratings for S. tritici resistance were based upon leaf damage recorded at water (GS71), milk (GS75), and dough (GS85) growth stages (GS) according to Zadoks et al. (3) using a double digit modified scale (1). All lines had the euploid 2n=6x=42 chromosome number with predominantly normal bivalent meiosis. The disease ratings of each of the 10 germplasms indicated their superior resistance over the three bread wheat cultivars (PiiO.05). In addition, we observed that these germplasms possessed resistance to leaf rust (caused by Puccinia triticina Eriks) and stem rust (caused by Puccinia graminis Pers.f.sp. tritici Eriks. & E. Henn.). All germplasms