Evaluation of sugarcane (<i>Saccharum officinarum</i> L.) somaclonal variants tolerance to salinity in vitro and in vivo cultures

Abstract

Tissue culture technique was used to obtain salt tolerant variants from embryogenic calli of sugarcane (Saccharum sp. Var. CP48-103) that were cultured on a selective medium containing different levels of NaCl (0, 33, 66, 99 and 132 mM). A total of four plants which regenerated from the tolerant calli were selected but the best in vigor were grown in in vitro and hydroponic systems under salinity stress (with the previous levels) as compared to source variety. With increasing supply of NaCl in both systems, root growth was more adversely affected than shoot growth. Chlorophyll contents showed a decreasing trend and dry matter yield of plants reduced but in a slow rate in tolerant somaclone than source variety. The tissues analysis showed that at high salt concentration, Cl^- and Na⁺ content in shoot and root increased. With rising salt concentration from 0 to 132 mM, content of Cl^- in shoot and root of tolerant variant changed and was lower than the parent. In conclusion, this variant probably had lowest genetic ratio of shoot: root chloride due to minimum transport of Cl^- from the root to shoot. Also this variant had high content of Ca²⁺ in shoot and high K⁺/Na⁺ ratio at all salinity levels. Thus, it probably has genetic potential to avoid harmful ions accumulation.

Key words: Sugarcane, salinity, somaclonal variation, in vivo, in vitro.