Evaluation of Freezing Tolerance of Brassica oleraceae purple rosette and Brassica oleraceae white rosette under Controlled Conditions

This study was conducted to determing freezing tolerance of Brassica oleraceae purple rosette(B.p) and Brassica oleraceae white rosette (B.w) at controlled conditions as a factorial complete randomized block design (RCBD) with four replications and 7 freezing temperatures (control, 0, -5, -10, -15, -20, -25, -30 Co). Chlorophyll fluorescence, chlorophyll content (SPAD), proline with cold tolerance were measured. By lowering the temperature chlorophyll fluorescence and chlorophyll content index decreased and on two spices maximal index exposed on control .Maximum proline average in -10o C (212.1 mmol/g) and in -5oC (189.2 mmol/g) exposed on B.p and B.w . Maximal significantly correlation (at the 0.01 level) exposed on chlorophyll content and Fv/Fm with temperature, the lower the temperature increased damages.