Selection for Resistance to Rice Sheath Blight Through Number of Infection Cushions and Lesion Type. D. E. Groth, Associate Professor, Rice Research Station, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, P.O. Box 1429, Crowley, LA 70527-1429. E. M. Nowick, Former Assistant Professor, Rice Research Station, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, P.O. Box 1429, Crowley, LA 70527-1429. Plant Dis. 76:721-723. Accepted for publication 6 March 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0721.

Individual plants from the first through third backcrosses of the rice sheath blight-resistant cultivar Tetep to the susceptible cultivar Lemont were selected for low infection cushion counts and for resistant-type lesions in the greenhouse. Replicated progeny field tests of selfed plants from each generation were conducted. Correlations between individual backcross plants, rated for number of infection cushions and lesion type, and disease ratings of their field-tested progeny were relatively low but resistance levels were maintained. No significant differences in disease ratings were observed among generation means for the first through third backcrosses in field tests. Sheath blight resistance was transferred to a Lemont plant type. Lesion type was the best and easiest selection criterion.

Keyword(s): Oryza sativa, Rhizoctonia solani.