Submitted to: Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/11/2013
Publication Date: 6/13/2013
Publication URL: http://handle.nal.usda.gov/10113/57428
Citation: Graybosch, R.A., St Amand, P., Bai, G. 2013. Evaluation of genetic markers for prediction of pre-harvest sprouting tolerance in hard white winter wheats. Plant Breeding. doi:10.1111/pbr.12071.
Interpretive Summary: Humid conditions during grain ripening can induce pre-harvest sprouting in wheat (Triticum aestivum L.). Pre-harvest sprouting results in the release of starch and protein degrading enzymes, with a concomitant loss of functional properties and seed quality, and severe financial impact. Selection for improved tolerance to pre-harvest sprouting is a goal of wheat breeding programs worldwide. From the onset of modern agriculture in the Great Plains of North America wheat production has been dominated by hard red winter and spring wheats. However, over the past 20-30 years, breeding programs initiated and continued the development of hard white wheats for use in the domestic production of whole wheat breads and in response to demand from export markets. White wheats, on average, are more susceptible to pre-harvest sprouting than red wheats. However, tolerant hard white wheats can be identified. Artificial means of induction of sprouting and selection for tolerance have been developed, but they are difficult and labor intensive. Selection using genetic (DNA) markers would improve the efficiency of selection for the trait. This study evaluated the value of previously identified markers linked to genes contributing to tolerance across multiple genetic backgrounds. A significant contribution to tolerance was demonstrated for QPhs.pseru-3AS, a gene previously identified from the hard white winter wheat Rio Blanco. The effect was detected in three of four investigated populations. In addition, positive contributions of additional genes were documented. DNA markers linked to loci contributing to variation in pre-harvest sprouting tolerance offer an efficient and effective alternative to direct phenotypic selection.
Technical Abstract: Pre-harvest sprouting of wheat results in significant financial loss at all steps in the production and marketing chain. Due to its intermittent nature in many wheat growing regions, direct selection for tolerance to pre-harvest sprouting is difficult. DNA markers linked to genes conditioning tolerance offer a more consistent and reliable approach to genetic improvement in tolerance. This investigation assessed the value of previously identified markers linked to quantitative trait loci contributing to tolerance, across multiple genetic backgrounds. A significant contribution to tolerance was demonstrated for QPhs.pseru-3AS, previously identified from the hard white winter wheat Rio Blanco. Marker alleles for this locus were associated with enhanced tolerance in three of four investigated populations. In addition, positive contributions of QPhs.pseru-2B1 and QPhs.pseru-2B2 also were documented. Simultaneous selection for putative marker alleles at two independent loci resulted in significantly higher mean tolerance scores, usually mediated by additive gene action. DNA markers linked to loci contributing to variation in pre-harvest sprouting tolerance offer an efficient and effective alternative to direct phenotypic selection.