SOMACLONAL VARIATION FOR RESISTANCE TO VERTICILLIUM-DAHLIAE IN POTATO(SOLANUM-TUBEROSUM L) PLANTS EGENERATED FROM CALLUS

Plant tissue culture is recognized as an important tool to generate us eful genetic variability for crop improvement. Regenerated plants from callus induced from stem explants of Solanum tuberosum cv Desiree wer e assessed by in vitro selection, for resistance to Verticillium dahli ae. This fungus is the causal agent of Verticillium wilt, a serious va scular wilt disease both in crops and wild species. The rate of in vit ro multiplication by single node cuttings was used as a parameter of s creening in two selection cycles with different concentrations of V da hliae filtrate. One resistant clone was selected and then evaluated by inoculation in the growth chamber. Induced damage, and morphological traits (dry weight, leaf area and tuber production) were estimated. Th e selected clone was comparable to the resistant control, cv Kondor. T he results suggest that genetic variation induced in tissue culture co uld be utilized to generate disease resistance.