Effect of different cultural practices on the performance of the red wine grape cultivar 'Malbec' recently grown in Bekaa, Lebanon

'Malbec' is a red wine grape cultivar recently introduced to Lebanon and is well-known for producing rich wines. In 2013, it was grown in Mansoura-West Bekaa and Der el Ahmar-North Bekaa. The research started in 2014 in order to observe the performance of 'Malbec' vines in separate growing systems with different climate conditions: system 1 (S1) at Der el Ahmar with no intervention on vine growth and nutrition and system 2 (S2) at Mansoura where canopy management and plant nutrition were adopted. Results showed that vines in S1 were less vigorous developing lower leaf number, leaf area, shoot number, shoot length and less productive, however in S1 earlier fruit veraison and maturity dates were reached. Linear and multiple regressions showed that the effect of climatic factors on vine growth and production was hidden by the effect of different agricultural practices. Consequently, in 2015, the effect of pruning and irrigation was investigated on S1 vines after harvest. Comparison between 3 treatments: T1(Irrg/Prn), T2 (NotIrrg/Prn) and control showed that fruit number and fruit weight were the highest in T2 and the combined effect of both practices (T1) resulted in the highest leaf formation, leaf expansion, fruit dimensions and yields. It induced as well a significant increase in productivity which was 15 times higher than the control. Fruit veraison and maturity dates were the earliest in control. Finally, it is recommended to prune and irrigate 'Malbec' vines after harvest for a better performance of this cultivar under the climate conditions of Bekaa.