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Title: Agronomic and quality evaluation of common wheat near-isogenic lines carrying the leaf rust resistance gene Lr47.

item BREVIS, J
item KHAN, I
item Morris, Craig

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2007
Publication Date: 7/1/2008
Citation: Brevis, J.C., Khan, I.A., Chicaaiza, O., Morris, C.F., Jackson, L., Dubcovsky, J. 2008. Agronomic and quality evaluation of common wheat near-isogenic lines carrying the leaf rust resistance gene Lr47. Crop Science 48:1441-1451.

Interpretive Summary: Leaf rust is a serious disease affecting wheat. Resistance to leaf rust may be achieved by adding specific resistant genes to wheat. One particular resistance gene, Lr47 was associated with an undesirable reduction in milling quality. Further work is needed in order to reduce these negative effects while still maintaining leaf rust resistance in wheat.

Technical Abstract: Wheat leaf rust caused by Puccinia triticina is responsible for significant yield reductions in wheat production worldwide. Genetic resistance is regarded as a cost-effective and environmentally-friendly tool to fight this disease and more than 55 leaf rust resistance genes (Lr) have been described so far. Even though nearly half of these Lr genes are derived from alien sources, their deployment into wheat cultivars has been limited. A likely explanation is the presence of negative effects associated with the introgression of chromosome segments carrying multiple alien genes. However, studies describing the agronomic and quality performance of lines carrying alien Lr genes under disease-free conditions are very limited. To fill this gap we present here a detailed characterization of the effect of the Lr47 introgression from Triticum speltoides in common wheat (Triticum aestivum) on agronomic performance, and milling and bread-baking quality parameters. Five pairs of hard red spring near isogenic lines were developed and evaluated in replicated field trials conducted between 2002 and 2004 in two locations each year. These experiments showed that the introgression of the T. speltoides chromosome segment including Lr47 is associated with detrimental effects in milling quality, mainly a significant decrease in flour yield (3%) and increase in flour ash (3%). Among the favorable effects, a 4 to 5 % increase in grain and flour protein was the most important. However, this increase in grain protein concentration appears to be offset by a small yield reduction (2.9%) associated with the presence of the Lr47 chromosome segment, since the total protein produced by hectare was not increased. In summary, these results suggest that the translocated alien segment needs to be further reduced to separate Lr47 from the negative effects on milling parameters.