Effects of different bud loads and irrigations applied at different leaf water potential levels on Kalecik Karası grape variety

Abstract

The effects of two irrigation practices (RDI-I and RDI-II) and two bud load treatments on the yield and quality of the Kalecik Karası red wine grape variety were studied. The midday leaf water potential thresholds were used for irrigation timing, and those values were set as -10 bars until flowering, -13 bars between the berry set-veraison and the veraison-ripening periods, and -12 bars after harvest for both irrigation treatments. Water volumes applied in the irrigations of the RDI-I plots were 50% and 75% of the cumulative evaporation from a class A pan between the berry set-veraison and veraison-ripening growth stages, respectively, while those portions for the RDI-II treatment were vice versa. The effects of control (K) and two-fold increased bud loads (2K) based on mean pruning weight on the grape yield and quality were also investigated. Irrigation and higher bud load treatments considerably increased grape yield in both years of the study. The highest and lowest grape yields were obtained in the RDI-II and the nonirrigated treatments, respectively. The increase in grape yield of irrigated vines in relation to nonirrigated ones was 53.3% in the first year and 54.3% in the second year. With doubling the bud load, the achieved increases in grape yield were 37.8% and 45.1% compared to the traditional bud loads in the first and the second year, respectively. The bud load effect was more apparent for the irrigated vines compared to the rain-fed cultivation. Cluster weight was also higher for the irrigated vines. These increases can most probably be related to improved canopy development under irrigation application. The leaf stomatal conductance was higher as a consequence of the higher soil water contents in both irrigated treatments. The improved gas exchange due to the stomatal openings led to a higher leaf area index as well as an increase in grape yield of the irrigated plants. Our findings reveal that the grape yield of the Kalecik Karası grape variety can be increased with irrigation and higher bud load applications. It is also worth noting that a limited irrigation application may help to maintain a better berry quality compared to the traditional rain-fed grape cultivation.

Influence of supplementation of vineyard soil with organic substances on nutritional status, yield and quality of ‘Black Magic’ grape (<i>Vitis vinifera L.</i>) and soil microbiological and biochemical characteristics

“…Irrigation was carried out when the average LWP value decreased to -1.2 MPa. When calculating the irrigation amount, 50 % of the evaporation values measured from the Class-A Evaporation Pan (METOS Inc., Mersin, Turkey) between irrigations was taken into account (Tangolar et al, 2015).…”