Description
The experiment was conducted at Department of Biochemistry, Main Cotton Research Station, Navsari Agricultural University, Surat. Twelve genotypes were selected for screening drought tolerance in first experiment. The seedling was subjected to 10 % PEG-6000 treatment for 48 hour and control was taken without PEG treatment. Two genotypes GSHV-172 and GISV-272 showed highest relative water content (72.31 and 70.36 %) in PEG treatment and 95.70 and 95.80% respectively in control while membrane stability index was found (83.43% and 86.76%) in GSHV-172 and GISV-272 respectively in PEG treated samples, Proline content was found higher in same genotypes. Genotypes GSHV-172 and GISV-272 showed highest chlorophyll stability index compared to other genotypes. So based on biochemical parameters GSHV-172 and GISV-272 found drought tolerant genotypes, rest of genotypes were moderately tolerance to drought susceptible. Total 12 RAPD primers were amplified to generate the 86 fragments and obtained 71 polymorphic bands. The cluster analysis showed the highest similarity 94% was observed between GISV-272 and GSHV-172 while, the lowest similarity 77% was observed between Surat dwarf and GSHV-01/13387. In second experiment, Two drought tolerant cotton genotypes (G1- GSHV-172 and G2- GISV-272) and two drought susceptible cotton genotypes (G3-BC-68-2 and G4- G. Cot. - 10) were selected from first experiment and grown up to 30 days in pots and the plants were subjected to three condition viz. control, drought (no water for 7days) and recovery condition (re-watering) for 7 days. Relative water content and membrane stability index were found higher in drought tolerant genotypes (GSHV-172 and GISV-272) compared to drought susceptible genotype (BC-68-2 and G. Cot.10). In control condition, proline, phenol, free amino acid, peroxidase activity and superoxide dismutase activity were found higher in drought tolerant genotypes compared to drought susceptible genotypes. In drought condition and recovery condition, proline, free amino acid, peroxidase activity and superoxide dismutase activity were found higher in drought tolerant genotype and drought susceptible genotype as compared to control.
