Genetics of resistance to powdery mildew (Microsphaera diffusa) in Brazilian soybean populations
Elaine Cristine Piffer Gonçalves1, Antonio Orlando Di Mauro2 and Maria Aparecida Pessôa da Cruz Centurion2
1Graduate Student, UNESP, Campus of Jaboticabal, Jaboticabal, SP, Brazil.
2Professor, UNESP, Campus of Jaboticabal, Jaboticabal, SP, Brazil.
Crosses between resistant and susceptible soybean cultivars were performed and the F2 populations were obtained to study the inheritance of soybean resistance to powdery mildew and to estimate the number and action of genes related to resistance. The reaction to powdery mildew was studied in a greenhouse and pots carrying plants with symptoms were distributed among the pots carrying the genotypes to be tested as a source of inoculum. Individual plants were scored according to the method of Yorinori (1997), with modifications, and classified as resistant or susceptible. The results showed that adult soybeans plants can present resistance to powdery mildew, which is controlled by one major gene with a dominant effect.
Key words: powdery mildew, Glycine max, genetic control.
Received: March 5, 2002; accepted: July 23, 2002.
Genet. Mol. Biol. vol.25 no.3 São Paulo 2002.