Chemically Induced Mutants of Brassica oleracea var. botrytis Maintained Stable Resistance to Drought and Salt Stress after Regeneration and Micropropagation

Abstract

Investigation was made to confirm the stability of drought and salt stress tolerance in cauliflower (Brassica oleracea var.botrytis) mutants after regeneration and micropropagation. The N-nitroso-N-ethyleurea (NEU) and N-nitroso-N-methylurea (NMU) induced mutants of cauliflower were created and screened for drought and salt stress tolerance. The highly tolerant mutants were selected, regenerated by tissue culture techniques, screened again for drought and salt tolerance under in-vitro and in-vivo conditions, correlated the response of in-vitro and in-vivo plants within a clone. Free proline levels in clones were correlated with stress tolerance. Results confirmed the persistence of mutations in clones with enhanced resistance levels to stresses over control plants. The regenerated in-vitro and in-vivo plants within a clone showed a positive significant correlation for drought (R2 = 0.663) and salt (R2 = 0.647) resistance that confirms the stability of mutation in clones after generations. Proline showed a positive and significant correlation with drought (R2 = 0.524) and salt (R2 = 0.786) tolerance. Conclusively, drought and salt resistance can be successfully enhanced in cauliflower by chemical mutagenesis. Further molecular analysis is recommended to study these mutants.