The effect of leaf on infection of Coffea genotypes by Hemileia vastatrix :
The ege a leaf at the time of inoculation affected both development of infection structures on the leaf surface and subsequent sporulation. In the case of the susceptible genotypes, cv. Caturra an line NC-169, there was a decrease in the number of appressoria formed, with an increase in age of fully expanded leaves. On the selected resistant line, NP-547, signicantly fewer appressoria were formed on the fourth leaf pair than on younger or older leaf pair. Appressoria were formed significantly more readily over stomata of leaf pair one, two, three, four and six than over five and seven of the susceptible selections. On the youngest leaf pair a significantly large percentage of appressoria formed away from stomata compared with the percentages obtained for older leaf pairs, where a large proportion of germinated uredospores did not form appressoria. The reaction type of the susceptible genotypes was a greater value on younger than older leaf pairs, and the reverse was true of the resistant genotype. The latent period (inoculation to sporulation) was shorter on NC-169 than on cv. Caturra. No uredospores formed on NP-547. Uredosorus density decreased with an increase in leaf age on the susceptible genotypes.
| Main Authors: | , , |
|---|---|
| Format: | biblioteca |
| Language: | eng |
| Published: |
1994
|
| Subjects: | COFFEA ARABICA, HEMILEIA VASTATRIX, CATURRA, HIBRIDO DE TIMOR, GENOTIPOS, ENFERMEDADES FUNGOSAS, INOCULACION, ESPORULACION, MICROSCOPIA, |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|