Narrow-sense heritabilities along the first decile of the daily relative extractable water (D1rew), for European larch (a, c) and Japanese larch (b, d), for the traits: ring width (a, b) and ring mean density (c, d). Narrow-sense heritabilities along the first decile of the daily relative extractable water (D1rew), for European larch (a, c) and Japanese larch (b, d), for the traits: ring width (a, b) and ring mean density (c, d). These heritabilities were computed from the variance parameters estimated with the multivariate, order 1 random regressions. Black line: narrow-sense heritability in pure species crosses; and gray line: narrow-sense heritability in hybridization (i.e., proportion of hybrid phenotypic variance that is due to the additive inheritance from each parental side). Dashed lines: 95% credible intervals. Alexandre Marchal et al. G3 2018;9:21-32 ©2019 by Genetics Society of America