Production of Triploid Grape Rootstocks by Embryo Culture and Their Growth Characteristics

Abstract

Embryo culture was utilized to obtain progenies from crosses between three diploid, female rootstock cultivars, 'Millardet et de Grasset 101-14' ['101-14' (2x), Vitis riparia Michx × V. rupestris Scheele], 'Millardet et de Grasset 41B' ['41B' (2x), V. berlandieri Planch. × V. vinifera L.] and 'Kober 5BB' ['5BB' (2x), V. berlandieri × V. riparia] and a tetraploid male rootstock cultivar 'Teleki 5C', ['5C' (4x), V. berlandieri × V. riparia]. Most of the embryos derived from these three cross combinations had globular and abnormal- or obscure-shapes. Four, three and two triploids were obtained from the embryos derived from '101-14' (2x) × '5C' (4x), '41B' (2x) × '5C' (4x) and '5BB' (2x) × '5C' (4x), respectively. The growth characteristics of a triploid derived from '5BB' (2x) × '5C' (4x), called E-1 (3x) were compared with '5BB' (2x) and its tetraploid ['5BB' (4x)] in the acclimating stage. Shoot and root growths and leaf morphology of E-1 (3x) were intermediate between those of '5BB' (2x) and '5BB' (4x). The growth of 'Kyoho' (V. × labruscana Bailey) grapevines micrografted onto '5BB' (2x), E-1 (3x) and '5BB' (4x) were also compared in the acclimating stage. The growth of scion shoot and root was the largest on '5BB' (2x), intermediate on E-1 (3x) and the smallest '5BB' (4x). In the aseptic co-culture of root segments and phylloxera (Daktulosphaira vitifoliae Fitch), E-1 (3x) and '5BB' (4x) was found to be highly resistant to the insect.