QUEENSLAND
CENTRE FOR RURAL & ENVIRONMENTAL BIOTECHNOLOGY
Faculty of Sciences, University of Southern Queensland, Toowoomba, QLD 4350, Australia.
www.usq.edu.au/creb/
Grant Daggard, Joan Vickers, Mark Sutherland, and Rob Learmonth.
Frost damage is a significant but unpredictable threat to spring wheat grown in Australia. Reducing frost risk by delaying planting reduces yields by up to 10 % annually. Conventional approaches to breeding for increased resistance have yet to be successful. This project, funded by Grains Research and Development Corportion (GRDC), aims at using a genetic approach to provide frost resistance via the introduction of novel genes that inhibit ice formation and/or ameliorate its effects on the wheat plant during flowering. Initial in vitro tests of transformed plants indicate a potential for improved frost tolerance that will be further evaluated by whole-plant testing.
Grant Daggard, Yihua Chen, Anke Lehmensiek, Mark Sutherland, Peter Williamson, and Miram Michalowitz.
Black point results in the discoloration of the embryo end of the grain and is associated with elevated humidity during grain development. A significant problem in most Australian wheat-growing areas, black point can cause losses of up to $50 x 10^6^ annually. This GRDC-funded project between the University of Southern Queensland and the Leslie Research Centre aims to locate molecular markers associated with black point resistance/susceptibility, which would allow rapid and reliable screening in breeding programs throughout Australia. A second objective is to obtain information on the actual genes involved in the symptoms of black point via use of ESTs for a better understanding of the underlying causes of the disease and to identify candidate genes.
Mark Sutherland, Bert Collard, Anke Lehmensiek, Grant Daggard, and G. Wildermuth.
This project will develop molecular markers for use in commercial breeding programs. Attributes of particular interest are those for whom phenotypic screening is expensive, time consuming, and strongly influenced by G x E interactions. Quality attributes of particular interest are milling yield, flour color and color stability, preharvest sprouting tolerance, water absorption, and extensibility. As part of our research into quality QTL, we are analyzing and refining wheat maps and phenotypic data sets accumulated within the Australian Winter Cereals Molecular Marker Programme.
Crown rot is a major constraint on wheat, barley, and durum production in the Northern Region grains belt. We recently have made major advances in identifying QTL that are linked to partial disease resistance in some hexaploid wheat sources. QTL from these different sources are being pyramided in an attempt to develop lines possessing improved resistance for commercial breeding.
SOUTH AUSTRALIA
THE UNIVERSITY OF ADELAIDE
Waite Campus, Plant Science, Glen Osmond, SA 506, Australia.
Daryl Mares, Kolumbina Mrva, Robert Asenstorfer, Richard Leach, and Anuja Kumaratilake.
Biochemistry and genetic control of factors that cause deterioration of wheat quality prior to harvest. Preharvest sprouting and tolerance to preharvest sprouting, grain dormancy, late maturity a-amylase, and black point. Our research aims to identify the environmental factors that trigger development of grain defects; identify tolerant genotypes and QTL/genes associated with tolerance; develop a better understanding of the mechanisms involved in tolerance; devise accurate and more effective phenotyping procedures based on field, controlled-environment, and biochemical screening; develop and validate molecular markers for tolerance; introgress tolerance into elite, locally adapted germ plasm; assist wheat breeders to incorporate new traits into breeding programs; and provide reliable information on wheat cultivars to wheat growers.
Biochemical and genetic control of color and color stability in Asian noodles. Grain and flour constituents involved in color of wheat flour and color and color stability in Asian noodles (xanthophylls, flavonoids, polyphenol oxidase, peroxidase,and lipoxygenase), nutritive aspects of cereal xanthophylls (lutein and lutein esters). This research aims to identify and quantify the biochemical constituents, enzymes and interactions that influence quality, specifically color, and, hence, the marketability of noodles; develop efficient, small-scale screening technologies for color and color constituents; identify QTL/genes associated with control of color components; develop and validate molecular markers for critical traits; and exploit available genetic variation, mutations, and synthetic wheats to develop wheat genotypes with improved or novel characteristics.
Daryl Mares and Kolumbina Mrva.
Preharvest sprouting periodically causes massive losses to the Australian wheat industry and affects all states, albeit with different frequency. Cultivar improvement, using dormancy from older white-grained genotypes introduced from South Africa and, more recently, landraces from China, has proven to be quite difficult due to inefficient screening techniques, strong environmental effects, a complex mode of inheritance, and a need for extensive capital and labor infrastructure. Despite these obstacles, parental germ plasm has now been developed that combines sprouting tolerance (tolerance eqivalent to the South African parental genotype AUS1408) with black point tolerance, absence of LMA, and low polyphenol oxidase in a locally adapted, semidwarf background. A major QTL associated with dormancy in this germ plasm corresponded to a QTL on chromosome 4A previously identified in the partially dormant Australian white wheat Halberd, and in some dormant red-grained cultivars overseas. The 4A QTL and its association with grain dormancy has now been confirmed in populations involving the Chinese sources of dormancy and in a population involving a dormant, single-gene red wheat. Eight SSR and two STS markers have been located within 110 cM with two SSR markers flanking the highest likelihood ratio statistic position.
Kolumbina Mrva and Daryl Mares.
Genetic control of LMA and the interaction with semidwarfing genes was investigated in wheat populations involving a number of the different LMA sources present in Australian and CIMMYT germ plasm (Spica, Seri, BD159, Kennedy, Cleo-Inia, Cranbrook, and RAC655) combined with different height reducing genes (Rht1, Rht2, and Rht1+Rht2) or the T1BL·1RS translocation. Cool temperature treatment of detached tillers was used to induce expression of LMA in lines carrying the defect. Preliminary results indicated that the QTL on the chromosome 7B and 3B, previously identified as controlling the expression of LMA in the cross 'Cranbrook/Halberd' also were associated with the high amylase phenotype in the crosses 'Spica/Maringa (Rht1)', 'Spica/Maringa (Rht2)', and 'Janz/BD159'. These QTL were independently effective and additive with the QTL on 7B having a greater effect than the QTL on 3B. Rht1 or Rht2 reduced the effects associated with each QTL, whereas LMA was extremely difficult to stimulate in lines containing Rht1+Rht2. In contrast to the Spica and BD159 populations, only the 3B region appeared to be associated with high amylase in the 'Hartog (no LMA, Rht2)/Seri (LMA, Rht1)' cross. This observation was unexpected since Seri produces very high levels of a-amylase despite the presence of Rht1. Regions on 3A and 7A homoeologous to 7B and 3B currently are being examined. When the 'Hartog/Seri' progeny were typed for T1BL·1RS, it was apparent that most lines with extremely high levels of alpha-amylase activity also possessed the T1BL·1RS translocation. Further investigation of the interactions between LMA QTL, Rht genes, and T1BL·1RS are in progress.