Comparison of Yield, Nut Quality and Growth Habit Among the ‘Forde', ‘Gillet', ‘Sexton' and ‘Tulare' Persian Walnut (Juglans regia L.) Cultivars

A field trial was established to evaluate the performance of the ‘Forde’, ‘Gillet’ and ‘Sexton’ Persian walnut cultivars that were released by the University of California, Davis Walnut Improvement Program in 2004 due, in part, to their low susceptibility to walnut blight caused by Xanthomonas campestris pv. juglandis. Paradox hybrid seedling rootstock was planted at a spacing of 5.8 x 5.8m in an offset configuration on a Hanford Sandy Loam soil in March 2004 at a site located in Modesto, California. The trees were grafted by a professional crew in April of the same year to Forde, Gillet, Sexton and Tulare. The ‘Tulare’ cultivar was included in the trial as a standard variety comparison. Harvest data taken in 2008, 2009 and 2010 indicates that in each year there was no significant difference between the yield of Gillet and Tulare. In all years Gillet and Tulare yielded significantly more than Forde. Sexton yield was comparable to that of Forde, but the data was not included in the analysis due to poor field establishment. Nut quality and value varied by attribute and year.