5 BB Kober or 5 BB Teleki is a V. berlandieri x V. riparia hybrid used as a rootstock. A vigorous rootstock, 5 BB is said to be the least reliable of the berlandieri x riparia hybrids, its quantity over quality aspect not always ideal, especially in cooler regions. In Bordeaux 5 BB was well suited to the compact, clay soils of the right bank in the 1960s during supply shortages of its V. berlandieri x V. riparia soul mate, SO4. It has good resistance to nematodes.
Dr Richard Smart in the Oxford Companion to Wine 4th edition ed. Jancis Robinson MW and Julia Harding MW (Oxford University Press, 2015, p.627.