TEXAS

TEXAS A&M UNIVERSITY

Texas A & M University Agricultural Research & Extension Center, 6500 Amarillo Blvd, West, Amarillo, TX 79106, USA.

Texas A & M University Agricultural Research & Extension Center, Rt. 7, Box 999, Beaumont, TX 77713, USA.

Texas A & M University Agricultural Research & Extension Center, 17360 Coit Road, Dallas, TX 75252, USA.

Soil & Crop Science Department, Texas A & M University, College Station, TX 77843, USA.

Texas A & M University Agricultural Research & Extension Center, Drawer E, Overton, TX 75684, USA.

Texas A & M University Agricultural Research & Extension Center, P.O. Box 1658, Vernon, TX 76384, USA.

Amarillo.

M.D. Lazar, G.J. Michels, Jr., C.D. Salisbury, J.D. Booker, J. Hu, G.L. Peterson, G.M. Piccinni, J.E. Simmons, and Q. Xue.

High Plains. The winter of 1994-95 was warmer than normal, and spring of 1995 was drier than normal (less than 2 in of precipitation fell at Bushland from January through April). Thus, greenbug was a severe, though erratic, problem for the second consecutive year. Later-maturing cultivars were higher yielding relative to early-maturing cultivars, because later cultivars were helped by significant May rain, whereas earlier cultivars were finished by that time. The highest irrigated yields were obtained from the cultivars TAM 200 and TAM 105 and the hybrids Quantum 588A and AP7501. The greatest dryland yields were produced by TAM 200, TAM 105, and Lamar.

Drought resistance. Variability in response to irrigation has been observed among sister selections of the pedigree `(TAM105*4/Amigo)*4//Largo' over several years of testing at Bushland. Seven such lines have been released as germplasm. Growth chamber experiments have established that the variability is related to specific physiological factors, particularly osmotic adjustment and total root length. These appear to result in differences in postanthesis dry matter accumulation and probably in the previously observed variation in total seed weight. Factors such as tillering and leaf morphology do not appear to be involved, though duration of green leaf retention under stress may be.

Greenbug resistance. Near-isogenic lines (NILs) for resistance/susceptibility to a specific greenbug biotype, E, were developed from a single plant of the pedigree `(TAM105*4/Amigo)*5//Largo'. Several NILs have been released. Resistance was found to be largely a result of antibiosis. All of the NILs also carry biotype C resistance derived from Amigo (Gb2). Biotype E resistance, derived from Largo and previously described as the single locus Gb3, has been determined to depend upon at least two unlinked loci, designated Gb3a and Gb3b. Biotype E greenbugs raised continuously on a resistant line over at least three generations were found to exhibit a greatly depressed, but constant, reproductive rate. Thus, the effect of the resistance is very significant, but not cumulative over generations.

Beaumont.

J. Sij.

A disease nursery in southeast Texas is being used by Texas small grain breeders to evaluate advanced lines for disease resistance. Southeast Texas is not a traditional wheat growing area, but the relatively warm, humid climate ensures high disease pressure in most years and aids selection procedures for breeders. Individual plant selections for evaluation have increased from 240 in 1995 to over 1,000 in 1996, not including advanced and uniform yield tests. Results are encouraging. Yields of 40+ bu/acre with commercial soft red winter wheat varieties are achieved routinely. Coker 9835 and Pioneer Brands 2571 and 2566 were among the top-yielding entries in 1995. Producers in southeast Texas have shown increasing interest in expanding soft red winter wheat acreage.

College Station.

Personnel. Dr. Charles A Erickson, a 20-year employee of the Texas Agricultural Experiment Station, resigned from his wheat breeding position at College Station in January, 1966. Dr. Erickson now has assumed his new duties as Assistant Curator of the U.S.D.A. World Collection of Small Grains at the National Small Grains Germplasm Research Facility at Aberdeen, Idaho.

During his period of employment in the Texas A & M University System, Dr. Erickson completed requirements for the PhD degree in Plant Breeding in December, 1990. He continued south Texas wheat improvement efforts after obtaining his degree. He made numerous contributions to the wheat breeding team in Texas, and we wish him every success in his new job.

Dallas.

D. Marshall, R.L. Sutton, and W.C. Wang.

In breeding work, the line TX89D9627 has been approved for release in 1996 as `TAM 301', a new hard red winter wheat cultivar. The pedigree of TAM 301 is `Mit/Kavkaz'. TAM 301 was selected for resistance to leaf rust, Septoria tritici blotch, and powdery mildew, in addition to all the agronomic and quality characteristics needed for a good hard wheat in central Texas. TAM 301 appears to carry the leaf rust resistance genes Lr1, Lr2a, Lr10, Lr26, and Lr34. The cultivar also carries the genes Sr31, for stem rust resistance, and Pm8 for powdery mildew resistance. TAM 301 performed well in the Blackland areas of central and north Texas and in the Rolling Plains of Texas. TAM 301 is susceptible to soilborne mosaic virus and to greenbugs.

In the Texas Blacklands for 1994-95, the three top-yielding hard red wheat cultivars were 2180 (40.4 bu/acre), Collin (39.8 bu/acre), and Ogallala (39.0 bu/acre). The three top-yielding soft red wheat cultivars were Pioneer 2571 (49.4 bu/acre), Pioneer 2566 (45.7 bu/acre), and Pioneer 2684 (44.9 bu/acre). The abnormally wet fall of 1994 favored the production of soft wheat over hard wheat.

Personnel. Marta Harrington left the program at Dallas to spend more time with her family.

Overton.

J. Crowder, L.R. Nelson, S. Ward, and C. Du.

Wheat grain yields in northeast Texas were below average in 1995. In the variety trail at DeKalb, Texas, `Pioneer 2580' produced a yield of 60 bu/acre. Test weights were also quite low, averaging about 56 lb/bu. Leaf rust was quite severe at Overton, however, many varieties showed good resistance. Powdery mildew was not a problem. Septoria glume blotch did reduce yields in 1995.

Publications.

Anonymous. 1995. Small Grain Notes, August 1995. Texas Agricultural Extension Service, Misc Pub. 32 p.

Crowder J, Ward S, and Nelson LR. 1994. Wheat grain variety tests at Dekalb and Mt. Pleasant for 1992-93. In: Overton Research Center Tech Rept 94-1:139-140.

Knowles TC, Hipp BW, Marshall DS, and Sutton RL. 1995. Plant nutrition and fertilizer management for winter wheat production in the Blackland Prairie. TAES Publ #B-1725. 28 pp.

Kurdyla TM, Guthrie PAI, McDonald BA, and Appel DN. 1995. RFLPs in mitochondrial and nuclear DNA indicate low levels of genetic diversity in the oak wilt pathogen Ceratocystis fagacearum. Curr Genet 27:373-378.

McDonald BA, Pettway RE, Chen RS, Boeger JM, and Martinez JP. 1995. The population genetics of Septoria tritici (teleomorph Mycosphaerella graminicola). Can J Bot 73(supplement):S292-S301.

Keller SM, McDermott JM, Wolfe MS, and McDonald BA. 1995. Recombination and gene flow in field populations of Phaeosphaeria nodorum. Phytopath 85:1132 (abstract).

Lazar MD and Simmons JE. 1995. Values of stress resistance genes relative to dry weight accumulation in wheat seedlings. Texas J Agric Nat Resour 8:45-52.

Lazar MD, Michels Jr. GJ, and Booker JD. 1995. Reproductive and developmental rates of two greenbug biotypes in relation to two wheat host resistance genes . Southwest Ent 20:467-482.

Lazar MD, Salisbury CD, and Worrall WD. 1995. Variation in drought susceptibility among closely related wheat lines. Field Crops Res 41:147-153.

Lister RM, Aboul-Ata AE, El-Daoudi YH, Marshall D, Makkouk K, Satour MM, Ghanem E, and Burnett PA. 1995. Serotyping of barley yellow dwarf virus isolates from Egypt. Phytopathologia Medit 33:152-157.

Marshall D, Gardenhire JH, Sutton RL, Rooney LW, Lazar MD, McDaniel ME, Nelson LR, and Worrall WD. 1995. Registration of `TAM 300' Wheat. Crop Sci 35:592-593.

Marshall D and Sutton RL. 1995. Epidemiology of stripe rust, virulence of Puccinia striiformis f.sp. hordei, and yield loss in barley. Plant Dis 79:732-737.

Nelson LR, Ward SL, and Crowder J. 1994. Forage variety tests for oat, rye, triticale, and wheat at Overton in 1993-94. In: Forage Research in Texas, 1994. TAES CPR-5252:25-31.

Nelson LR, Barnett RD, Marshall D, Erickson CA, McDaniel ME, Worrall WD, Tuleen NA, and Lazar MD. 1994. Registration of TX76-40-2 Wheat Germplasm. Crop Sci 31:1137.

Philley GL and Nelson LR. 1990. Powdery mildew control and yield response with Baytan seed treatment. Fungicide and Nematicide Tests 46:291.

Wang WC and Marshall DS. 1995. Optimization of particle bombardment conditions for long-term stable expression using GUS gene in wheat. In Vitro Cell Dev Biol 31:3-10.

Worrall WD, Porter KB, Lazar MD, Gomex MH, Marshall DS, Nelson LR, and McDaniel ME. 1995. Registration of `TAM 109' Wheat. Crop Sci 35:1223.

Worrall WD and Young K. 1995. Bar coding in plant breeding research. Proc 24th Soybean Seed Research Conf Dec. 6-7, 1994, Chicago, IL. Publ No 24, Am Seed Trade Assoc.