Selection of KDML105 Calli Tolerance to Glyphosate

Abstract

Calli of KDML105 were selected for glyphosate-tolerance on solidified 0.25% Phytagel^®-solidified MS (Murashige and Skoog, 1962) selection medium (MS salts and vitamins, 1 mgl^-1 kinetin, and 10^-4 M glyphosate) at 25±2 °C, 70±5 μmol m^-2s^-1 photosynthetic photon flux density (PPFD), and 16 hd^-1 photoperiod. Calli fresh weight were decreased in selection medium more than in glyphosate-free medium. The selected calli at 4 and 8 weeks (S₄ and S₈) could be regenerated on the glyphosate-free medium. Plantlets were propagated by tissue culture technique and treated with 0, 10^-5, 5×10^-5 and 10^-4 M glyphosate in vitro. The height of S₄ and S₈ plantlets was decreased with increasing glyphosate concentrations in culture media. The number of tillers and number of roots were increased in culture media supplemented with 10^-5 M glyphosate. The S₈ plantlets could survived on the culture supplemented with 5×10^-5 M glyphosate. Increasing the height of plantlets indicated high survival percentage under glyphosate-stressed condition. Tolerant plants were transferred to pots and treated with 0, 250, 500, 1000 and 2000 mgl^-1 glyphosate. The growth of plants was inhibited and phytotoxicity was observed when treated with high glyphosate concentrations. Increasing glyphosate concentrations resulted in lesser toxicity in S₈ plantlets than in S₄ plantlets.