Genetic mapping and QTL analysis for terminal drought tolerance in Wheat(Triticum aestivum L.)
Cakir, M., Waters, I., Rebetzke, G., Conocono, E., Drake-Brockman, F., Stefanova, K., Wilson, R., Barclay, I., McLean, R. and Setter, T. (2011) Genetic mapping and QTL analysis for terminal drought tolerance in Wheat(Triticum aestivum L.). In: Wheat Breeding Assembly 2011, 24 - 26 August 2011, Citigate Hotel, Perth.
Recent drought events have caused substantial yield loses in Australia and therefore genetic improvement of drought tolerance has become a high priority in wheat breeding programs. As some Western Australian wheat varieties have shown high levels of water soluble carbohydrates (WSC) at anthesis, understanding the role of WSC in terminal drought tolerance has been the primary focus of our recent drought research. The objectives of this study were to evaluate the impact of stem WSC at anthesis on drought tolerance during grain filling and map the genes responsible for the accumulation of stem carbohydrates and grain yield. Two doubled-haploid (DH) populations, Westonia/Kauz (W/K) and Westonia*2/Janz (W/J), were studied in the field environment under conditions where water supply was manipulated. The analysis of grain yield data showed 3 to 5-fold variation in under drought conditions. Transgressive segregation was observed for grain yield in both populations. Stem carbohydrate concentrations at anthesis varied 2.5 fold with concentrations ranging from 200 to 500 mg per g stem dry weight. From the 32 wheat varieties tested, six varieties had drought tolerance (i.e. grain yield under drought relative to control conditions > 0.9). Varieties with <300 mg g-1 WSC, also had low drought tolerance (relative grain yield< 0.8). Genetic maps were constructed for W/J and W/K populations using 306 and 469 markers, respectively. QTL analysis indicated the presence of several genes for stem WSC concentration and content on chromosomes 3A, 4B, 4D and 7B for the W/J population, and 2D, 5B, 6B for the W/K population. Further results with the grain yield data and the breeding value of some of the wheat DH lines will also be discussed.
|Publication Type:||Conference Item|
|Murdoch Affiliation:||Western Australian State Agricultural Biotechnology Centre|
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