Cultivation of hazelnut tree trained with double vertical spindle shape

A five-year (2011-2016) study was performed to evaluate the maximum yield obtainable per unit area in two orchards of 'Tonda Gentile delle Langhe' located in Daruvar, Croatia. The trees in the first orchard were planted at 5×4 m distance and trained as vase shape. Trees in the second orchard were planted at 3×0.7 m distance and trained as double vertical spindle on the support which consisted of piles, horizontal crossbars and wires. Yield was determined each year of both orchards. The results showed that plants trained with double vertical spindle gave a lower yield 
tree^-1 but a significantly higher yield in total due to the narrow planting distances and the larger number of trees in a unit area. Nut and kernel weights and the number of blanks were similar in both training systems. The double vertical spindle training system requires a higher starting investment in new orchards but shows great potential due to the higher and earlier yield.