GrainGenes

Resistance to Pyrenophora tritici-repentis.

R.G. Rees, P.S. Brennan, G.J. Platz, and K.C.M. Blaikie.

The extended drought in Queensland continued during 1994, and those wheat crops planted were generally poor. Once again, this resulted in limited carryover of infested wheat residues and very limited inoculum of P. tritici-repentis for the 1995 wheat season.

Efforts to develop yellow-spot-resistant wheats adapted to northeastern Australia continue. This involves a backcrossing program augmenting adapted varieties with resistance from a range of sources. Several advanced lines are at the final yield and quality evaluation stage, and, we hope that a release will be made in the near future. Adapted lines developed in the program are being used increasingly as resistance sources, reducing the backcrossing required. Several new sources of resistance have been included form material provided by Dr. M. Kohli, CIMMYT, Paraguay.

Soilborne disease research.

G.B. Wildermuth, R.B. McNamara, and T.M. Sparks.

Drought continued to plague the wheat-growing areas of Queensland in 1994, and wheat planting was reduced severely. Crown rot (caused by Fusarium graminearum) occurred in some of the crops that were planted. Crown rot also occurred extensively in bread wheat crops in western Victoria and in bread and durum crops in South Australia.

Field tests to screen advanced breeding lines for their reaction to crown rot were conducted with the aid of irrigation. Twenty cultivars and advanced lines from the Queensland and University of Sydney wheat breeding programs were tested. All except Pelsart, a variety tolerant to root-lesion nematode, were susceptible or highly susceptible to the disease. Single replicates of some durum cultivars and lines also were tested, and most were highly susceptible to the disease.

The same cultivars and lines from the breeding programs also were tested for their reaction to common root rot caused by Bipolaris sorokiniana. Four lines showed resistance comparable to that of the resistant standard, Kite. Two of three durum cultivars, Yallaroi, and Wollaroi also showed resistance comparable to that of Kite. The resistance in the durum cultivars contrasts with their high susceptibility to crown rot.

Publication.

Wildermuth GB and McNamara RB. 1994. Testing wheat seedlings for resistance to crown rot caused by Fusarium graminearum Group 1. Plant Dis 78:949-953.

Markers for wheat quality attributes.

S.J. Kammholz, R. Ramage, M.W. Sutherland, G. Daggard, R.J. Henry, R.J. Marschke, M. Petroff, D.J. Martin, B. Stewart, and P.S. Brennan.

The project attempting to locate molecular markers for several wheat quality characters has made sound progress over the past 12 months. Seven of the eight doubled haploid populations originally required for the project now have been developed. Seed from these lines now is being increased and will be made available to interested researchers over the next few years.

The doubled haploid lines that have been developed to locate markers for flour colour (Sonalika/Hartog; Klasic/Hartog) and short dough development time (Gamenya/Hartog; Neepawa/Hartog) will be grown in replicated field trials this coming winter. The quality determinations from these trials should allow lines to be classified as either high or low for the targeted attribute. This should allow molecular profiles to be developed and any polymorphisms to be identified. The doubled haploid lines developed to identify markers for high flour yield and extensibility will be field tested in the winter of 1996.

University of Queensland

St Lucia, Q 4072, Australia.

Finding protein markers for wheat quality attributes.

R. Ramage and M. Sutherland.

Many research groups have identified correlations between the presence of certain glutenin and gliadin proteins in wheat seed and its dough and bread making properties. Unfortunately, these correlations are not always the same, particularly for the gliadins, and no attempt has been made to use the information obtained in a large-scale breeding program.

Research is currently underway at the University of Southern Queensland to identify a one-dimensional electrophoretic technique that will reliably identify any consistent correlations between storage protein composition and the wheat quality attributes; flour yield and colour, dough strength, extensibility, and short dough development time. It is proposed that such correlations can be used as markers for the early selection of these characters. For this reason, the technique needs to be time- and cost-efficient and capable of screening large numbers of populations.

The widely used SDS-PAGE technique for reduced, whole-protein extracts of single grains or whole-meal samples is under investigation. Various run times, staining techniques, gel lengths, concentrations, and gradients are being examined to determine optimum conditions for maximum protein separation and polymorphism. Separate extraction procedures for glutenin subunits and gliadins of high and low molecular weight also are being investigated.

Germplasm enhancement program for high yield and protein of wheat in the northern region.

M. Cooper, A. Peake, and P.S. Brennan.

The University of Queensland and the Queensland Wheat Research Institute have initiated a population improvement program to provide high yield and high protein parents for the wheat breeding programs of the northern region of the wheat belt of Australia. The project is concentrating on evaluating and incorporating germplasm, from breeding programs around the world into backgrounds with local adaptation. The population improvement program has a long-term focus and is being conducted as a recurrent selection program for yield improvement. An aim is to incorporate a dominant male sterile gene into populations to assist cycles of intercrossing. Yield and protein evaluation are based on multi-environment trials conducted at four sites for 2 years. At each site, soil nitrogen is manipulated to provide two contrasting management regimes and examine yield protein relationships. Lines from the recurrent selection program currently are being produced by either single-seed descent or production of doubled haploids by use of the maize crossing system.

Development of optimum strategies for multi-environment testing in the northern region.

I. DeLacy.

A project, funded by industry, to optimise the yield testing strategy for the two wheat breeding programs in the northern wheat belt of Australia has been in progress for a year and a half. The northern wheat belt in Australia covers an area from the Queensland Central Tablelands, starting north of Emerald (Lat. 23 S) in the tropics to just south of Tamworth in New South Wales (32 S); a span of 900 km. The crop is grown in the winter and is harvested in the spring or early summer to minimise the risk of a late frost. The crop relies heavily on stored soil moisture and consequently is restricted to heavy soils with cracking clays (mostly vertisols) and a high water-holding capacity. The majority of Australia's high quality ('prime hard') wheat is produced in this region.

The project, which is funded to run for 5 years, has four parts. Part A is a retrospective analysis of the historical data, from 1974 to the present, of the three levels (preliminary, intermediate, and advanced) of breeder multi-environment trials. Part B consists of investigating the correlation of performance of a set of common lines entered in stage 2 trials for 3 years and their performance in a measure of long-term performance in commercial production. Both parts are aimed at optimising the number of replications, sites, and years at each stage and elucidating any regionality in the adaptation of the test lines. Part C consists of collection of appropriate phenological, growth, and weather data from automatic stations at each trial site. These data, together with historical weather data, will give another characterisation of site regionality by the use of wheat crop growth models. This will be associated with the historical and experimental data from parts A and B. Part D will integrate cost data, collected from the breeding and yield testing programs, with the experimental data to derive an optimum, cost-efficient, yield-testing strategy for the region.

Mailing list.

Queensland Wheat Research Institute, PO Box 2282, Toowoomba Q 4350, Australia - P.S. Brennan, R.G. Rees,

G.B. Wildermuth, and S.J. Kammholz.

University of Queensland, St Lucia Q 4072, Australia - R. Ramage, M. Cooper, and I. DeLacy.

The University of Sydney

IA Watson Wheat Research Centre, Narrabri, Australia.

L. O'Brien, F.W. Ellison, D.J. Mares, and S.G. Moore.

Rainfall during the 1994 season was the third lowest recorded in any year at Narrabri since recording commenced in 1871. The season promised much, with good rains in February and early March, but a planting rain never occurred. The growing season rainfall, 66 mm from 1 April to 30 October, was the lowest ever recorded. Access to irrigation meant that all breeding material was protected and advanced a generation. The dry conditions resulted in the absence of stripe rust for the first time since the disease arrived in Australia in 1979.

Some regional trials were planted with the cooperation of district agronomists from NSW Agriculture and Prime Wheat Association who located growers willing to use scarce irrigation water to support our trials. A new collaborative initiative was implemented in 1994. The Northern Wheat Improvement Program combines the resources and skills of the University with those of the Queensland Department of Primary Industries and NSW Agriculture. The program provides joint regional testing and disease and support screening services to the bread wheat and durum wheat breeding programs for the northern wheat areas of Australia. The University of Sydney is responsible for collaborative yield testing, rust screening, and sprouting tolerance screening services for the program.

Two new prime hard quality wheats, covered by PVR, will be released for commercial production in 1995. Sunland is a main-season maturing wheat with resistance to the three rust diseases. Sunvale is also a main-season maturing, rust-resistant wheat with tolerance to the root lesion nematode.

Dr. R. Trethowan left the program to take up a position as Wheat Breeder at the Victorian Institute for Dryland Agriculture at Horsham.

PBI Cobbitty and Department of Crop Sciences

Cobbitty, NSW, 2570; and Sydney, 2006, Australia.

K. Adhikari, J. Bell, L.W. Burgess, G.N. Brown, C. Zhao, H-S. Hwang, S. Johnston, Z. J. Lu, D.R. Marshall, J.D. Oates, R.F. Park, J.E. Roake, P.J. Sharp, S.X-Ren, D. Singh, F. Stoddard, A. Thomas, M. Turner, and C.R. Wellings.

Rust pathogenicity surveys.

Because of drought conditions, there were few reports of rust in 1994. A few crops near Deniliquin, in southern NSW, and Bordertown, S.A., were sprayed to control stripe rust. One isolate of stem rust from Queensland yielded the old pathotype, 21-0, which had not been sampled since the 1970s.

Host resistance studies.

The location of Sr10 on chromosome 2B has been confirmed with linkage studies. Close linkage was shown within Lr23, suggesting a location in 2BS. As predicted from both local and overseas work, a number of Australian

wheats were shown tentatively to possess Lr34/Yr18, both reported sources of durable resistance. These include Egret, Flinders, Meering, Osprey, Oxley, Reeves, and Sunstar. On the other hand, cultivars Blade, Gutha, Harrier, Kewell, and Tatiara do not possess these genes, which do not confer adequate resistance on their own. An allele of the T. dicoccoides-derived gene, Yr15, was found in durum wheat. In contrast to the highly resistant phenotype (IT 0;=) associated with Yr15, the new allele is characterized by necrosis (IT ;NN). All Australian isolates are avirulent for both genes. A gene for stripe rust resistance in Selkirk and a number of CIMMYT-generated wheats, including Ciano 79 and Bluejay 'S', was located on chromosome 2B. Telocentric mapping and linkage studies have localised it in the vicinity of Yr5/Yr7, which may be allelic.

Near-isogenic lines with genes for resistance to stripe rust are being developed in a selection of the cultivar Avocet. We are seeking international collaborators to assess the lines as potential differentials for field use. Preliminary results indicate that they will be useful in areas where the Avocet selections are susceptible.

Staff.

Amanda Bennett completed her Ph.D. studies and has a temporary position with the CSIRO Grain Quality Research Laboratory. C.R. Wellings will spend 4 months at ICARDA, Syria, from March. R.F. Park has been awarded a Humboldt Fellowship and will spend approximately 1 year with Dr. F. Zeller at Freising, Germany, from April. Dr. D. The will retire in August after 20 years of service with the National Wheat Rust Control Program. Mr. Z.J. Lu and S.X. Ren are visiting scholars from China.

N. Darvey triticale and rye breeding.

Two advanced, longer-season, dual-purpose triticale lines, II81-207, and Tall Madonna (9501 reselection), will be submitted for preliminary PVR in 1995. One rye line, Super Rysun Reselection (934B), will be increased by registered seed growers on behalf of the Institute and George Weston Foods Ltd. with a view to preliminary PVR and release to contract seed growers in 1996. 934B is rust-resistant and substantially outyields earlier cultivars.

A `hybrid' triticale program has commenced with a view to producing high quality grain for human consumption.

Tissue culture.

Genes for meiotic restitution of haploids aimed to circumvent colchicine treatment and for high green regeneration response following anther culture have been established in a few advanced spring triticale lines.

Further improvements to our isolated microspore culture system for wheat and triticale were achieved. Regeneration dishes with several green and no albino plants have resulted from isolated triticale microspores.

Our `wheat x maize' system has been improved significantly with the use of maize cv. Kelvedon Glory, regularly giving 11-13 embryos per spike and moderate (>50 %) conversion of embryos into plants.