A computer program to improve the efficiency and accuracy of postulating race-specific resistance genes.
Yeshi A. Wamishe, Department of Plant Pathology, University of Arkansas, Fayetteville 72701; Kevin C. Thompson, Agricultural Statistics Laboratory, University of Arkansas, Fayetteville 72701; and Eugene A. Milus, Department of Plant Pathology, University of Arkansas, Fayetteville 72701. Plant Dis. D-2004-0311-01S, 2004 (online).
Accepted for publication 5 January 2004.

Race-specific resistance genes that are expressed in the seedling stage have been used to protect wheat from leaf rust caused by Puccinia triticina. Combinations of several genes provide better protection than one or a few genes. Knowing which resistance genes are in particular wheat lines (cultivars and breeding lines) would allow breeders to choose parents for developing new cultivars with particular combinations of resistance genes. The objective of this study was to develop a computer program to facilitate identification of race-specific resistance genes in wheat lines. For each line, step 1 of the program used data from P. triticina races that attacked the line, and these data definitively excluded genes that cannot be present in the line. Step 2 of the program utilized data from races that did not attack the line and produced a concise table of data that was then examined visually to determine which resistance genes were present and which may be present in the line. This program would be especially useful for identifying a large number of resistance genes in a large number of lines with a large number of races and also could be adapted to host–pathogen systems other than leaf rust of wheat.

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