ISHS Acta Horticulturae 747: VIII International Symposium on Protected Cultivation in Mild Winter Climates: Advances in Soil and Soilless Cultivation under Protected Environment
INDUCED RESISTANCE OF TOMATO TO WHITEFLIES AND PYTHIUM WITH THE PGPR BACILLUS SUBTILIS IN A SOILLESS CROP GROWN UNDER GREENHOUSE CONDITIONS |
| Authors: | A. Hanafi, M. Traoré, W.H. Schnitzler, M. Woitke |
| Keywords: | soilless, salinity, resistance, tolerance, whitefly, Bemisia tabaci |
| Abstract:
The development of biological products based on beneficial micro-organisms can extend the rage of options for maintaining the health yield of crops. It has been recognized that the application of the Rhizobacterium Bacillus subtilis BS confers vitality as well as the capacity of the plant to face with the conditions of biotic and abiotic stress such as drought and salinity. These stress conditions prevail in the Mediterranean regions, where a proportion of farmers use saline water for the irrigation of their crops. In our experiments, we evaluated the impact of BS, used in salinity stress and non stress conditions, on the resistance and tolerance of soilless tomatoes grown under greenhouse, to the whitefly Bemisia tabaci and the root fungal pathogen Pythium sp. Two levels of salinity (EC = 6dS/m and EC = 2.4 dS/m) were used for irrigation of tomato plants inoculated and none inoculated with BS. Two cultivars of tomato were evaluated in this experiment. On one hand, the cultivar ‘Durinta’ (Western seeds) is relatively tolerant to salinity, whereas the cultivar ‘Tyjico’ (Syngenta Seeds) is sensitive to salinity. On the other hand, the cultivar ‘Durinta’ is sensitive to tomato Yellow leaf curl virus (TYLCV). In contrast, the cultivar ‘Tyjico’ is tolerant to TYLCV. TYLCV is a Gemini virus exclusively transmitted by the whitefly B. tabaci. TYLCV is by far the number one virus disease of greenhouse tomatoes in the Mediterranean region. This study concluded that irrigation of tomato with saline water (E C 6) makes the plant less sensitive to the whitefly B. tabaci. On the other hand, the inoculation of plants with Bs appears to induce plant resistance to B. tabaci, whether in salinity or non salinity stress conditions. Regarding the incidence of Pythium, the inoculation of plants with Bs induced resistance to this root pathogen, especially under saline conditions. | |
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