Resistance to soybean rust [Phakopsora pachyrhizi] and mode of inheritance.

Reference Report for IND80072553

Title:	Resistance to soybean rust [Phakopsora pachyrhizi] and mode of inheritance.
Authors:	Bromfield, K.R., Hartwig, E.E.
Source:	Crop Sci. 1980, 20(2):254-255
Abstract:	A study was conducted in containment facilities to determine the reaction to Phakopsora pachyrhizi Syd. (soybean rust) isolates from widely separated geographic areas on 7 soybean [Glycine max (L.) Merr.] strains rated moderately resistant in field planting in Taiwan. The mode of inheritance of resistance to several rust isolates was also studied. Soybean strains PI 230970 and PI 230971 were resistant when inoculated with P. pachyrhizi isolates Australia-72-1, India-73-1, Philippines-77-1 and Taiwan-72-1. The other 5 soybean strains, although rated moderately resistant in field planting in Taiwan, were rated susceptible in these studies. All were rated resistant to an isolate with low virulence from Puerto Rico. Individual trifoliolate leaves of soybean plants of an F2 population of 'Centennial' .times. PI 230970 were inoculated with rust isolates from 3 different geographic areas. Plants rated as resistant to one isolate were resistant to all isolates. Similarly, plants rated susceptible to 1 isolate were susceptible to all isolates. A ratio of 92 resistant to 31 susceptible was obtained. Twenty-five F2 plants from the cross D75-10169 .times. PI 230971 gave 19 resistant and 6 susceptible plants after inoculation with the Taiwan isolate. The results suggest a single dominant gene for resistance to soybean rust.

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