EARLY PERFORMANCE OF THREE WALNUT CULTIVARS IN TWO TRAINING SYSTEMS
In 1994 all cv. 'Serr' trees were completely trained in both systems, and even 100% of ‘goblet’ trained trees were ready at the fourth growing season. 'Hartley' proved to be easier to train in central leader than in ‘goblet’ and ‘Vina’ showed the opposite behavior.
The higher vigor of 'Serr' gave a larger cumulative weight of wood cut by pruning (1990–1994). Last year the amount of annual cut wood was low in 'Serr' as a consequence of its earlier training. We spent three h/ha more training in central leader than in ‘goblet’.
Trees had a higher production and reached it earlier in ‘goblet’ than in central leader. This is clearly true in 'Serr'; this cultivar, till 1994, produced nearly double in ‘goblet’ than in central leader. Yield per trunk unit (cumulated nut production/cm2=cumulative efficiency), at seven years, is the same in 'Vina' as in 'Serr' but in 'Hartley' is less than 10% of the others. Results showed that cumulative efficiency depends on the training system. So far, ‘goblet’ has been the best.