The effect of different irrigation regimes on the indigenous Cypriot grape variety Xynisteri and comparison to Sauvignon blanc

Aims: The aims of this study were to (1) assess the response of the indigenous Cypriot variety Xynisteri to different irrigation regimes and (2) compare the performance of Xynisteri to Sauvignon Blanc grown in pots with different irrigation regimes.

Methods and Results: The investigation involved two irrigation trials conducted in Lemesos, Cyprus during the 2019 season. Irrigation trial one was established in a commercial Xynisteri vineyard. Three different irrigation regimes – full irrigation, deficit irrigation (50%) and no irrigation were used. Irrigation trial two was a potted trial of Xynisteri established from cuttings collected from two different regions (KX and ZX) and Sauvignon blanc. Three irrigation regimes – full irrigation, deficit irrigation (50%) and minimal irrigation (25%) were applied to ten treatment replicates.

Vine performance, vine phenology and bunch architecture measures were taken at five developmental growth stages during the growing season in both trials. Fruit composition analysis, yield (field trial only) and shoot, trunk and root weights measurements were performed at the end of the season.

Very few differences between measures were found between irrigation regimes in the commercial vineyard. However, in 2019 the vineyard received 194mm of rain in the growing season (April-September). Fruit composition analysis revealed fructose to be lowest in the full irrigation group compared to deficit and non-irrigated treatments.

The potted trial demonstrated that for all three irrigation regimes, both Xynisteri KX and ZX had higher stem water potential, stomatal conductance and chlorophyll content when compared to Sauvignon blanc. Additionally, Xynisteri KX had higher chlorophyll content with minimal irrigation compared to the Xynisteri ZX. 

Furthermore, Xynisteri KX and ZX produced greater end of season root, trunk and shoot weights than Sauvignon blanc under all irrigation regimes and Xynisteri KX had greater root, trunk and shoot weights than Xynisteri ZX with full irrigation

Conclusions: 

This study identified the greater potential for the indigenous Cypriot grape variety Xynisteri to cope successfully with hot and dry conditions when compared to Sauvignon blanc. It also highlights the possible existence of different biotypes that may be important for future clonal selection.

Significance and Impact of the Study: The world’s changing climate is placing great pressure on the resources for sustainable viticulture in warm/hot wine growing regions. Many vineyards and wineries base their businesses on European grape varieties traditionally grown in regions with abundant water resources. It is therefore necessary for these wine regions to investigate grape varieties that are indigenous to hot climates. The eastern Mediterranean island of Cyprus is one such place with 12 indigenous grape varieties that grow well in a hot climate without irrigation.