Linkage Relationships in Soybean Between Genes Controlling Reactions to Phytophthora Rot and Metribuzin1
- T. C. Kilen and
- W. L. Barrentime2
Linkage between desirable and undesirable genes increases the population sizes required to recover preferred gene combinations and hinders the progress of breeding programs. The soybean [Glycine max (L.) Merr.] cultivar Tracy is resistant 15 of the 20 identified races of Phytophthora megasperma Drechs. f. sp. glycinea Kuan and Erwin, but it also has an undesirable gene conferring sensitivity to the herbicide metribuzin [4-amino-6tert-butyl-3-(methylthio)-as-triazin-5(4H)-one]. The objectives of this study were to determine the inheritance of sensitivity to metribuzin found in Tracy, to determine if the genetic basis for sensitivity in Tracy was related to that previously described in ‘Semmes’, and to examine possible linkage relationships between genes for phytophthora rot resistance and metribuzin sensitivity. The results suggest that the sensitivity to metribuzin in Tracy is controlled by the same recessive gene, hm, that controls sensitivity to metribuzin in the cultivar Semmes. A combined recombination estimate of 7% between genes Rps1 (for phytophthora rot resistance) and Hm was determined from repulsion and coupling crosses which suggests close linkage between the two loci.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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