Qualitative and quantitative variation in pathogenicity of races of coffee leaf rust (Hemileia vastatrix) detected in the State of Sao Paulo, Brazil :
Of 7 qualitatively distinct new races, 4 carried complex virulence against the resistant genes SH1, SH2, SH4 and SH5 of Coffea canephora; 3 matched unidentified resistance genes. Two of these were isolated from Kouillou and 1 from Icatu (Is. 2, 10 and 11). Is. 2 and Is. 10 showed extra virulence to some coffee genotypes and decreased virulence to others. Three isolates were detected which differed quantitatively from the common race II. Is. 1 was moderately virulent to the coffee differential for SH3 in the lab. but avirulent in the glasshouse. Is. 3 and 12 showed levels of virulence intermediate between race II and Is. 2 and 10 respectively. Results showed that incomplete resistance of coffee of H. vastatrix, at various levels, can be race specific. The nature of race formation of the disease in Brazil and breeding strategies for obtaining durable resistance are discussed
| Main Author: | |
|---|---|
| Format: | biblioteca |
| Language: | eng |
| Published: |
1983
|
| Subjects: | COFFEA CANEPHORA, HEMILEIA, ROYA, ENFERMEDADES FUNGOSAS, VIRULENCIA, SAO PAULO, GENOTIPOS, BRASIL, HEMILEIA VASTATRIX, RAZAS FISIOLOGICAS, KOUILLOU, ICATU, |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Of 7 qualitatively distinct new races, 4 carried complex virulence against the resistant genes SH1, SH2, SH4 and SH5 of Coffea canephora; 3 matched unidentified resistance genes. Two of these were isolated from Kouillou and 1 from Icatu (Is. 2, 10 and 11). Is. 2 and Is. 10 showed extra virulence to some coffee genotypes and decreased virulence to others. Three isolates were detected which differed quantitatively from the common race II. Is. 1 was moderately virulent to the coffee differential for SH3 in the lab. but avirulent in the glasshouse. Is. 3 and 12 showed levels of virulence intermediate between race II and Is. 2 and 10 respectively. Results showed that incomplete resistance of coffee of H. vastatrix, at various levels, can be race specific. The nature of race formation of the disease in Brazil and breeding strategies for obtaining durable resistance are discussed |
|---|