Effects of Gelling Agents and Antioxidant Treatments on In Vitro Potato Micro-Tuberization and on Common Scab Development Using Virus-Indexed Plantlets

摘要

A VIRUS- FREE (free from PVA, PVM, PVS, PVX, PVY and PLRV) plantlets of potato cv. "Alpha", "Diamant" and "Spunta" were obtained by tissue culture technique and further used throughout this study. A significant improve in the micro-tuberization of thetested potato cutivars "Alpha", "Diamant" and "Spunta" was obtained when corn starch was used instead of the gelling agent agar in the tissue culture media. Potato cv, "Spunta" gave the best growth characters in vitro, i.e, number of micro-tubers (1.26micro-tubers/ plantlet),fresh weight as well as dry weight of micro-tubers(106.51 and 17.89 mg/plantlet). Amendment corn starch medium with ascorbic acid (AA) caused significant increase in the micro-tuberization while these characters were significantlydecreased in the medium supplemented with salicylic acid (SA). Micro-tubers variously responded to Streptomyces scabies the causal agent of potato common scab, infection depending on potato cultivars. The micro-tubers of potato cv." Spunta" showed the highest susceptibility followed by "Diamant". Complete inhibition of S. scabies growth (colony number and size of colony mm)was expressed when cultured on the growth medium amended with 1.0, 5.0 or 10.0 mM SA and when SA combined with CaCl_2 at rate 1.0 mM CaCl_2 with 1.0, 5.0 or 10.0 mM SA, but AA alone or with CaCl_2 decreased the growth of S. scabies.