EVALUATION OF HIGH YIELDING CANOLA TYPE BRASSICA GENOTYPES/MUTANTS FOR DROUGHT TOLERANCE USING PHYSIOLOGICAL INDICES AS SCREENING TOOL

An experiment was conducted to assess the effect of various water regimes on growth and yield of canola genotypes/mutants using physiological indices as screening tool, in the year 2007-08. Three canola type genotypes viz., Con-III, Hyola-42 and Shiralee (Check) and two mutants of Rainbow viz., Rainbow-1 (R-75/1) and Rainbow-2 (R-100/6) (including Rainbow-Parent) were selected for the study. The mutants of Rainbow were developed by the Brassica Group of NIA, Tandojam. The experiment comprised of four water regimes i.e., W-1 (300 mm), three irrigation of 100 mm each at flowering, siliquae formation and at maturity stage; W-2 (200 mm), two irrigations of 100 mm each at flowering and siliquae formation stage; W-3 (100 mm), single irrigation of 100 mm at flowering stage and W-0 (no irrigation) except soaking one. Relative water contents (RWC), Osmotic potential (OP) and potassium contents were generally decreased whereas total greenness (Spad value) and proline contents increased under various water regimes as compared to control. The present study showed that the genotype Con-III and the mutant Rainbow-2 (R-100/6) were relatively tolerant to drought stress as compared to all other genotypes/mutants.