Association mapping identified quantitative trait loci (QTLs) and the markers linked to pre-harvest sprouting (PHS) resistance in an elite association mapping panel of white winter wheat comprising 198 genotypes. A total of 1,166 marker loci including DArT and SSR markers representing all 21 chromosomes of wheat were used in the analysis. General and mixed linear models were used to analyze PHS data collected over 4 years. Association analysis identified eight QTLs linked with 13 markers mapped on seven chromosomes. A QTL was detected on each arm of chromosome 2B and one each on chromosome arms 1BS, 2DS, 4AL, 6DL, 7BS and 7DS. All except the QTL on 7BS are located in a location similar to previous reports and, if verified, the QTL on 7BS is likely to be novel. Principal components and the kinship matrix were used to account for the presence of population structure but had only a minor effect on the results. Although, none of the QTLs was highly significant across all environments, a QTL on the long arm of chromosome 4A was detected in three different environments and also using the best linear unbiased predictions over years. Although previous reports have identified this as a major QTL, its effects were minor in our biparental mapping populations. The results of this study highlight the benefits of association mapping and the value of using elite material in association mapping for plant breeding programs.

We report the discovery of a new hydroxylated abscisic acid (ABA) metabolite, found in the course of a mass spectrometric study of ABA metabolism in Brassica napus siliques. This metabolite reveals a previously unknown catabolic pathway for ABA in which the 9-methyl group of ABA is oxidized. Analogs of ()-ABA deuterated at the 8-carbon atom and at both the 8-and 9-carbon atoms were fed to green siliques, and extracts containing the deuterated oxidized metabolites were analyzed to determine the position of ABA hydroxylation. The results indicated that hydroxylation of ABA had occurred at the 9-methyl group, as well as at the 7-and 8-methyl groups. The chromatographic characteristics and mass spectral fragmentation patterns of the new ABA metabolite were compared with those of synthetic 9-hydroxy ABA (9-OH ABA), in both open and cyclized forms. The new compound isolated from plant extracts was identified as the cyclized form of 9-OH ABA, which we have named neophaseic acid (neoPA). The proton nuclear magnetic resonance spectrum of pure neoPA isolated from immature seeds of B. napus was identical to that of the authentic synthetic compound. ABA and neoPA levels were high in young seeds and lower in older seeds. The open form (2Z,4E)-5-[(1R,6S)-1-Hydroxy-6-hydroxymethyl-2,6-dimethyl-4-oxo-cyclohex-2-enyl]-3-methyl-penta-2,4-dienoic acid, but not neoPA, exhibited ABA-like bioactivity in inhibiting Arabidopsis seed germination and in inducing gene expression in B. napus microspore-derived embryos. NeoPA was also detected in fruits of orange (Citrus sinensis) and tomato (Lycopersicon esculentum), in Arabidopsis, and in chickpea (Cicer arietinum), as well as in drought-stressed barley (Hordeum vulgare) and B. napus seedlings.

Crop development and species diversity are important aspects of the emerging global bioeconomy, as is maximizing crop value through total crop utilization. We advocate development of Brassica carinata as a biorefinery and bioindustrial oils platform using traditional and molecular breeding techniques and tools. We review genetic studies and breeding efforts to develop elite B. carinata germplasm, work involving development of transformation and regeneration protocols, target gene isolation, and transgene expression. Genetic modification strategies using a B. carinata breeding line as a delivery platform for very long‐chain fatty acid‐enhanced/modified oils are presented as case studies. The target oil products are erucic acid (22:1 Δ13), docosadienoic acid (22:2 Δ5, Δ13) and nervonic acid (24:1 Δ15); in addition transgenic efforts to enhance B. carinata seed oil content are discussed. The overall advantages and current limitations to utilizing this crop are delineated. Other anticipated biobased products from a B. carinata platform may include, but are not limited to, the production of biolubricants, biofuels and biopolymers from the oil, biopesticides, antioxidants, as well as plant gums, and vegetable protein‐based bioplastics and novel food and feed products. In summation, this collaborative B. carinata breeding/germplasm development/value‐added molecular modification effort will not only contribute to the development of renewable feedstocks for the emerging Canadian bioeconomy (biorefinery/bioproducts), but also promises to generate positive economic and environmental benefits. Published in 2010 by John Wiley & Sons, Ltd.

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