Effect of gelling agents onin vitro tuberization of six potato cultivars

The gelling agent Phytagel™ was compared with Difco Bacto-agar forin vitro tuberization of six potato cultivars (Jaerla, Blanka, Claustar, Kennebec, Désirée, and Baraka). On a culture medium with 6% sucrose but lacking growth regulators, tuberization was higher when Phytagel™ was used rather than Difco Bacto-agar, regardless of the photoperiodic regime used. Chemical analyses of the gelling agents revealed a higher mineral content and organic impurities in Bacto-agar than in Phytagel™, which is therefore recommended for microtuber production. The same gelling agent should be used in all treatments of microtuberization experiments in order to draw meaningful physiological conclusions.