Article ID: OKD-009
The growth and berry quality of ‘Ruby Roman’ (Vitis labruscana) grapevines grafted on two species of rootstock, ‘Kober 5BB’ [‘5BB(2×)’] (V. berlandieri × V. riparia, a semi-dwarf rootstock) and ‘Hybrid Franc’ [‘HF(2×)’] (V. rupestris × V. vinifera, a vigorous rootstock), and their colchicine-induced autotetraploids [‘5BB(4×)’ and ‘HF(4×)’] were investigated through 2 years of pot cultivation followed by 2 years of ground cultivation. During the nursery stage, the survival rate and root and shoot growth of the grafted cuttings in the two diploid rootstocks were obviously greater than in their corresponding tetraploids. During subsequent cultivation in pots and in the ground, the grapevines grafted on ‘5BB(4×)’ had less shoot growth (weight and length), shorter internode length, and in some cases smaller stem diameter than those grafted on ‘5BB(2×)’. However, in contrast with ‘5BB’, there was no significant difference in total vine growth between ‘HF(2×)’ and ‘HF(4×)’ during pot cultivation, and the total shoot length and weight in the ‘HF(4×)’ grapevine was greater than in ‘HF(2×)’ during ground cultivation in 2014. After 2 years of pot cultivation, the root growth of the ‘HF’ (diploid and tetraploid) rootstocks was more vigorous than that of the ‘5BB’ (diploid and tetraploid) rootstocks. In addition, the proportions of the thin roots (diameters <1 mm) in the two diploid rootstocks [‘5BB(2×)’ and ‘HF(2×)’] were greater than those in the two tetraploid rootstocks [‘5BB(4×)’ and ‘HF(4×)’]. In contrast, the proportions of the thick roots (diameters 1–2 mm, 2–5 mm, and >5 mm) in the two diploid rootstocks were less than those in the two tetraploid rootstocks. Furthermore, the berries of ‘Ruby Roman’ harvested from the grapevines grafted on ‘5BB(4×)’ exhibited a much deeper skin coloration than those harvested from the other grapevines.