ITEMS FROM THE UNITED STATES

 

TEXAS

TEXAS A&M UNIVERSITY

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

TAES TAMU Research & Extension Center at Dallas, 17360 Coit Rd., Dallas TX 75252-6599 USA.

 

TAES Research & Extension Center at Overton, P.O. Box 200, Overton, TX 75684, USA.

Amarillo: M.D. Lazar, G.L. Peterson, M. Balota, Y. Weng, W.A. Payne, G.J. Michels, Jr., C.M. Rush, and B.W. Bean.
Dallas: D.S. Marshall and R. Sutton.
Overton: L.R. Nelson and S. Ward.

[p. 297-298]

High Plains. The 1999-00 crop year featured spotty autumn moisture, leading to very poor stands of dryland wheat in some areas. Relatively late planting combined with the dry winter to produce poor pasture conditions for stocker cattle. Warmer than normal autumn and winter temperatures aided massive greenbug outbreaks over much of the region. The best irrigated grain yields at Bushland were for TAM 200 (77 bu/acre), TAM 201 (77 bu/acre), TAM 110 (76 bu/acre), Trego (73 bu/acre), and Hickok (72 bu/ac). Under dryland production at Bushland, Custer, Hickok, TAM 110 and Jagger each produced between 48 and 50 bu/acre. At Conway, east of Amarillo, where autumn moisture and greenbugs were each less plentiful, top varieties were TAM 107 (32 bu/acre), Thunderbolt (31 bu/acre), and Hickok (31 bu/acre). An advanced breeding line, TX95A3091, is under increase for release as a new dryland wheat variety with an excellent dryland yield record, tall semidwarf stature, and medium maturity.

A preliminary investigation of methods of screening for drought response has suggested that canopy temperature depression (CTD) may be a general method that integrates several resistance mechanisms. We have evaluated three BC3 sister lines differing in yield response to irrigation, TX86A8072 (resistant), TX88A6880 (intermediate), and TX86A5606 (susceptible). CTD was continuously (24 hrs/day) evaluated on dryland plots at Bushland, between booting and mid-grain filling. Differences between genotypes were generally small (< 0.5°C), but repeatable and statistically very significant. Especially consistent were differences measured in the early morning (predawn). This study is currently being repeated.

North Texas. We have introgressed resistance to leaf rust from four sources of Ae. cylindrica, thre sources of T. monococcum, one source of Ae. tauschii, and one source of Ae. triuncialis (Table 1). Initial inheritance studies indicate resistance in each case is controlled by a single, dominant gene. Some progress has been made in developing molecular markers for the genes in order to develop multiple gene combinations. The genes appear to be different from each other, as well as different from other wild relative sources.

East Texas. Wheat acreage surveys indicate that there were about 400,000 acres of SRWW grown in Texas in 1999-00. Much of this wheat was utilized as a dual-purpose crop (forage and grain) and approximately 300,000 acres were harvested as a grain crop. Wheat grain yields in the high-rainfall area near Overton, TX, in 2000 were very high with mean yields near 92 bu/acre. Coker 9663, Coker 9704, and Roane, which produced yields of 113, 109, and 108 bu/acre, respectively, produced the highest yields. An advanced breeding line, TX91-57, produced a yield of 106 bu/acre. The pedigree of TX91-57 is 'Gore/FL85377G3-26', which should indicate decent flour quality. However, early flour testing indicates poor quality. This line shows very good disease resistance and seed is being increased for possible release. Mean yields in the Mt. Pleasant and DeKalb variety trials were 64 and 52 bu/acre, respectively. Leaf rust, stripe rust and powdery mildew were moderately severe in 2000. Fifty percent of all advanced wheat lines were discarded because of their susceptibility to powdery mildew. Stagonospora nodorum disease levels were low in 2000; however, resistant breeding lines were detected in several nurseries.

Personnel. [p. 298]

Dr. Bill Payne joined the faculty at Amarillo/Bushland in April, 2000 as crop stress physiologist. Dr. Maria Balota joined the program at Amarillo in January, 2000, as a Fulbright scholar, visiting from Fundulea, Romania. Dr. Balota is currently continuing her research in wheat physiology as a postdoctoral research associate. Ms. Marie Gasingirwa is an M.S. student at West Texas A&M University and a Fulbright scholar, working at Amarillo on mapping AFLP loci relative the the Gb3 greenbug-resistance locus.

Publications. [p. 298]

• Crowder J, Ward S, and Nelson LR. 2000. Wheat forage yields at Overton for 1998-99 and three-year means. In: TAMU - Overton Beef Field Day Report, April 2000. Research Center Technical Report No. 00-1. pp. 53-54.
• Fritts DA, Michels Jr GJ, and Lazar MD. 2000. Greenbug colongy formation failure on a resistant winter wheat genotype: antixenosis, antibiosis or both? Southwestern Entomol (In press).
• Piccinni G, Rush CM, Vaughn KM and Lazar MD. 2000. Lack of relationship between susceptibility to common root rot and drought tolerance among several closely related wheat lines. Plant Dis 84:25-28.
• Ward S, Crowder J, and Nelson LR. 2000. Rye forage yields at Overton for 1998-99 and three-year means. In: TAMU - Overton Beef Field Day Report, April 2000. Research Center Technical Report No. 00-1. pp. 55-56.
• Ward S, Crowder J, and Nelson LR. 2000. Oat forage yields at Overton for 1998-99 and three-year means. In: TAMU - Overton Beef Field Day Report, April 2000. Research Center Technical Report No. 00-1. pp. 57-58.