Segregation of red leaf characters in grapevine rootstock hybrid populations

• Author(s): Boyden, L.; Cousins, Peter;
• Abstract: Grapevine (Vitis spp.) rootstocks can be very similar in appearance to the fruiting varieties grafted on them. Obvious morphological markers that can be used to distinguish rootstock shoots from those of the scion would facilitate grapevine grafting and vineyard establishment and management. A similar strategy is used in peach orchards, where a red leaf character is used to identify rootstocks. We are incorporating obvious morphological markers into grapevine rootstock populations. Grapevines expressing the red leaf factor have bright red leaves in the fall, and young seedlings have reddish shoot tips, stems, and buds. The red leaf factor is considered to be due to a dominant single allele, although its relationship to other anthocyanin regulatory genes in grapevine has not been described. We studied the segregation of red leaf characteristics in four populations, derived from crosses of four grapevine rootstock varieties, none carrying the red leaf factor. The rootstock varieties were the interspecific hybrids Harmony, Freedom, 5A, and 5BB. The sources of the red leaf factor were Alicante Bouschet, a V. vinifera cultivar (parent of three populations) and HN12, a complex interspecific hybrid cultivar (parent of one population). Seedlings were grown in a greenhouse and scored for color at about one month of age. Two hundred eight seedlings were scored overall. In all four populations, segregation of seedlings for presence or absence of red leaf characteristics was consistent with a 1:1 ratio. We conclude that both Alicante Bouschet and HN12 are heterozygous for the red leaf factor. The red leaf factor can be introduced into grapevine rootstock genetic backgrounds and its expression and segregation in those genetic backgrounds is consistent with its behavior in grapevine scion cultivar populations.
• Publication Date: Aug 2003
• Journal: Hortscience