Pedigree diagram of ‘Chandler’ and other walnut cultivars released by the UC Davis walnut breeding program. The values in parentheses after cultivar names represent coefficients of parentage (COP) of a cultivar with ‘Chandler’. If COP is 0, the variety has no lineage relationship with ‘Chandler’. The pairwise COPs were calculated based on the definitions in and. The cultivars in bold font are parents or ancestors of ‘Chandler’. The percentages of heterozygous loci are in square brackets behind some cultivars.