HYBRID AND SELFED SEEDLING PROGENIES OF VITIS HYBRID 'ROGER'S RED' GRAPE SEGREGATE FOR TENDRIL DISTRIBUTION

Abstract

Grapevines of most species and cultivars produce lateral meristems (tendrils and inflorescences) on at least two successive nodes in three. Lateral meristems complicate rootstock cutting production, since tendrils are removed from rootstock cuttings prior to propagation and since tendrils clinging to wires, canes, or other tendrils make collecting cuttings more time consuming and expensive. To develop improved grapevine rootstocks with reduced lateral meristems, an elite nematode resistant rootstock selection ((Vitis berlandieri × V. riparia) × V. biformis) was crossed with ?Roger?s Red? (Vitis hybrid), and ?Roger?s Red? was also self-pollinated. Seedlings from controlled pollinations were grown in a greenhouse and trained up a stake. Starting at the first node in alternate phyllotaxy (that is, a node with a lateral meristem) and continuing for twelve nodes, the presence or absence of lateral meristems was observed and the type of lateral meristem was reported. There were 141 cross-pollinated seedlings. There were 83 seedlings from ?Roger?s Red? self-pollination. The expected pattern of lateral meristem distribution was wild type: two successive lateral meristem bearing nodes, followed by a single lateral meristem-free node. However, 43 of 83 seedlings from ?Roger?s Red? self-pollination showed two or more successive lateral meristem-free nodes (flanked by lateral meristem-bearing nodes), and 12 of these 43 showed at least two sets of two successive lateral meristem-free nodes. One self-pollinated seedling showed three successive lateral meristem-free nodes in the alternate phyllotaxy. In contrast, in the hybrid population only 33 of 141 seedlings showed the non-wild type pattern of two successive lateral meristem-free nodes, and only 6 of these 33 showed at least two sets of two successive lateral meristem-free nodes. Tendril distribution is under genetic control and the production of extra tendril-free nodes was segregating in these populations. Dominant alleles at two genes are required for the mutant phenotype. A genetic model and the gene names Successive Tendril free Node-1 and Successive Tendril free Node-2 are proposed.