ISHS Acta Horticulturae 586: IV International Symposium on Olive Growing
DIFFERENTIAL REACTIONS OF ACCESSIONS OF CV. TONDO SASSARESE TO OLIVE LEAF SPOT |
| Authors: | M.P.M. Mungianu, L. Otgianu, G. Tolu, V.A. Prota, U. Prota |
| Abstract:
Olive leaf spot induced by Spilocaea oleagina (Cast.) Hughes, the most serious fungal disease of olive in Sardinia, prevails in the area of cultivation of cv. Tondo Sassarese, which is especially susceptible to the disease. Field surveys and laboratory tests were conducted over a 5-year period (1994-1998) for establishing timing, distribution and intensity of infections, evolution of infected leaf areas as well as trend and severity of defoliation. Comparative obervations were carried out on olive trees that were fully exposed to natural fungal infections and trees that were protected by fungicide treatments. They were applied according to indications derived from laboratory tests for the early detection of fungal attacks. Among non protected trees a clear-cut differential behaviour was observed with respect to fungus-induced premature defoliation. The response of individual trees to defoliation was consistent over time and statistically significant when the data from homogenous groups of trees were comparatively worked out. In particular, based on leaf shedding, accessions denoted nT2 and nT5 exhibited a remarkable tolerance to S. oleagina infections since their defoliation rate did not differ statistically from the trees that had been protected by spraying. These results are taken as evidence that in the population of cv. Tondo sassarese there are interesting sources of tolerance to “leaf spot” which should be taken in consideration in clonal selection, and might represent useful starting material for programmes of genetic improvement for resistance. | |
|
Download Adobe Acrobat Reader (free software to read PDF files) | |
