Heritability of adventitious rooting of grapevine dormant canes

One of the most important viticultural characteristics of a grapevine rootstock is the ability to form roots on dormant lignified canes (rootstrike). North American species of Vitis are the primary source of germplasm for grapevine rootstocks and vary widely in their rate of rootstrike. Breeders have hybridized grape species in order to introgress traits to produce commercial rootstocks. A combination of 26 parents consisting of improved and wild accessions of Vitis spp. was used to generate 27 families. The percentage of rootstrike of dormant canes was observed over several years for 552 individuals. A logistic generalized linear mixed model (GLMM) method was used to estimate the narrow sense heritability (h²) of rootstrike. Heritability was found to be moderate (h² = 0. 307 ± 0. 050). The model also estimated breeding values of all parents and progeny. A GLMM method can be used to estimate breeding values of germplasm to identify individuals with commercially acceptable rates of rootstrike with a defined probability of transmitting this trait to progeny. This is useful for the introgression of traits into potentially new commercial rootstocks. The pattern of normal distribution of rooting indicates that it is possible to identify individuals with good rootstrike from Vitis species that are generally considered to have low rootstrike. Selection of individuals with a higher breeding value will increase the efficiency of rootstock breeding.