Effect of indole-3-acetic acid and kinetin on tuberisation parameters of different cultivars and transgenic lines of potato in vitro

The effect of indole-3-acetic acid or kinetin on the weight and number of m icrotubers formed was studied on single node cuttings of seven different po tato (Solanum tuberosum L.) cultivars as well as transgenic lines harbourin g rolB or rolC genes under control of the patatin class I (B33) promoter. P lants were cultivated in vitro in the dark on solidified MS medium containi ng 1 to 8% sucrose with or without phytohormones. Most of the nontransforme d potato cultivars and transgenic lines responded to hormone application by an increase in tuber yield. Auxin and cytokinin acted differently: IAA inc reased predominantly the tuber size while kinetin increased the number of t ubers. RolC transformants displayed an altered response to sucrose and espe cially to auxin. The degree of phytohormone effect on tuberisation paramete rs depended on sucrose content of the medium and potato genotype.