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Aluminium (Al) toxicity in acid soils continues to be a major concern for crop production, especially for wheat which is a moderately tolerant cereal crop species. So far, Al tolerance was known to be controlled by few genetic loci detected clearly by classical mapping studies. Here, we report the outcome of a genome wide association mapping approach in bread wheat ( Triticum aestivum L.) using 525 Diversity Array Technology markers genotyped in a core collection of 96 winter wheat accessions. Marker-trait associations (MTAs) were detected using both general linear model (GLM) and mixed linear model (MLM). Five significant MTAs were identified as shared by models on chromosomes 1A, 1D, 3B and 6A. Highly significant MTAs were identified by MLM on chromosomes 1D and 3B which could be new candidate loci for future studies. Some of our results are in line with prior reports, but some appear to be novel. Potential candidate genes have been searched in respective chromosomal bins for highly significant MTAs detected by MLM. The loci identified in our study have the potential to improve Al tolerance in wheat and hence need to be verified and utilized for breeding tolerant cultivars worldwide. [ABSTRACT FROM AUTHOR]

Marker-trait associations identified in diverse germplasm can be exploited in crop improvement programs. An attempt to establish such associations was made by evaluating 205 wheat landraces for stripe rust, leaf rust and stem rust responses in the field over three crop seasons. Diversity arrays technology was used to genotype the landraces and associations were identified using a single-marker scan. Sixty-eight markers were significantly associated with rust resistance. Several significantly associated loci coincided with the presence of known major genes or QTL for rust resistance. In contrast, many marker-rust response associations identified in this analysis for each of the three rust diseases uncovered new loci. Dual associations; stripe rust-leaf rust (1AL, 2BS, 2BL, 3DL, 5BS, 6BS and 7DL), leaf rust-stem rust (5BL) and stripe rust-stem rust (4BL and 6AS) resistance were also observed. These associations could enable a cost-effective targeted mapping of dual rust resistance. Some marker-trait associations identified in this study have been validated through genetic analyses and formal naming of resistance loci. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB) caused by Fusarium species, is among the most devastating wheat diseases, causing losses in numerous sectors of the grain industry through yield and quality reduction, and the accumulation of poisonous mycotoxins. A germplasm collection of spring and winter wheat, including nine reference cultivars, was tested for Type II FHB resistance and deoxynivalenol (DON) content. Genetic diversity was evaluated on the basis of Simple Sequence Repeat (SSR) markers linked to FHB resistance quantitative trait loci (QTLs) and Diversity Arrays Technology (DArT) markers. The allele size of the SSR markers linked to FHB resistance QTLs from known resistance sources was compared to a germplasm collection to determine the presence of these QTLs and to identify potentially novel sources of resistance. Forty-two accessions were identified as resistant or moderately resistant to Fusarium spread, and two also had very low DON concentrations. Genetic relationships among wheat accessions were generally consistent with their geographic distribution and pedigree. SSR analysis revealed that several resistant accessions carried up to four of the tested QTLs. Resistant and moderately resistant lines without any known QTLs are considered to be novel sources of resistance that could be used for further genetic studies. [ABSTRACT FROM AUTHOR]