Vigor — hybrids between Vitis rotundifolia Michx. and Vitis vinifera L.

First-generation (F1) interspecific hybrids between V. vinifera and V. rotundifolia typically possess high growth vigor, inherited from the V. rotundifolia parent. However, subsequent generations obtained through backcrossing often display insufficient growth vigor, necessitating rigorous selection in the breeding process.

The evaluation of this trait in these hybrids is based on a comparison with the performance of parent forms or standard V. vinifera cultivars. A significant feature is the inheritance of biological properties from V. rotundifolia, such as rooting difficulties in cuttings, which indirectly affect the overall growth vigor and the success of propagating hybrid plants.