Article / Resistance to viral and fungal diseases in local cucurbit cultivars from the arid regions of Tunisia

Elbekkay, M., Hamza, H., Desbiez, C., Djebali, N. (In press) Resistance to viral and fungal diseases in local cucurbit cultivars from the arid regions of Tunisia. Genetic Resources and Crop Evolution. https://doi.org/10.1007/s10722-024-02233-7

Résumé : The oases environment is favourable for the development of several diseases and the proliferation of insects that transmit viruses. The selection and breeding of local cultivars of cucurbits for resistance to these biotic constraints is the most economic control strategy. Thus the evaluation of resistance of local melon, watermelon and squash cultivars (cv.) to seven viruses (CMV, ZYMV, WMV, PRSV, MWMV, MNSV and TolCNDV) and two fungal pathogens Fusarium oxysporum f. sp. melonis (FOM, races 1 and 2) and Podosphaera xanthii (race 1 (strain Sm3), race 2 (strain S87-7), race 3 (strain 00SM39), race 5 (strain 98Sm65) and race 3–5 (strain 04Sm2)) was made. The results showed that 26 out of 44 cultivars evaluated, exhibited resistance for at least for one of the studied pathogens. The local cucurbit cultivars were generally resistant to MNSV and ToLCNDV in comparison to commercial cultivars. Specifically, melon cultivars M5 and M18, and squash cv. C46, C60 and C65 were resistant to WMV. Watermelon cultivars P15 and P24 along with squash cultivar C60 exhibited resistance to CMV. Partial resistance to MWMV was observed in melon cultivars M35 and M129, watermelon cultivars P35 and P55, and squash cultivar C65. Only C65 squash cv. was resistant to PRSV. For fungal pathogens, the local melon cultivars M6, M26, M58, M120, M131 were resistant to race 1 of FOM, and all studied cultivars were susceptible to race 2 of this fungus. Two local melon cultivars M120 and M122 were resistant to P. xanthii races 1, 2 and 3. The wild desert bitter watermelon was resistant to WMV, MNSV, CMV, MWMV and ToLCNDV, but not to PRSV. This study demonstrated that the Tunisian cucurbit genetic resources present valuable material for improving resistance to viral and fungal diseases in these crops.