Determination of sodium chloride stress tolerance of some rapeseed (Brassica napus L.) cultivars under in vitro conditions

This research was carried out at the Tissue Culture Laboratory of Erzurum Eastern Anatolia Agricultural Research Institute according to the "Split – Split Plot Design in Randomized Blocks" with three replications. Shoot tip, hypocotyl and cotyledon explants of Elvis and Californium canola (Brassica napus L.) genotypes were used in the study. In addition to control media (T0: 0.0 mM NaCI) , 5 different NaCl concentrations (T1: 25mM, T2: 50 mM, T3: 75 mM, T4: 100 mM, T5: 150 mM) were added to MS media to culture explants. Explants were incubated under long-day photoperiod conditions (16 h light, 8 h dark) for 6 weeks. At the end of the 6th weeks, following observations were taken: days to the first shoot appearence; plantlet survival rate; the length of shoots, roots and nodes; the number of shoots, roots and nodes; diameter of leaves; fresh and dry weight of plantlets. As a result of the study, it was seen that Elvis genotype had much more significant better plantlet characteristics compared to Californium cultivar. Shoot tip and cotyledon explants gave better results compared to hypocotyl explants. The best shoot regeneration from media was obtained in salt combination media containing 50 mM NaCl, control media and media containing 25 mM NaCl salt. The Californium variety (9.19 days) started to shoot earlier than Elvis variety (9.56 days), but the Elvis variety (23.74 mm) gave longer plantlet (Californium, 22.37 mm). Shoot lengths of 33.11 mm, 24.69 mm and 11.36 mm were determined in the shoot, cotyledon and hypocotyl explants, respectively. The longest plantlets among the medias; control media (36.33 mM), followed by 25 mM NaCI (33.56 mM) and 50 mM NaCl (31.56 mM) salt media. As a result of the study, it can be concluded that Elvis genotype, shoot tip and cotyldeon explants determined better shoot development up to 50 mM NaCl concentration, however increased salt concentration resulted a significant decrease on plantlet growth characteristics in examined genotypes and explants. Key words: Brassica napus L., tissue culture, in vitro, NaCl stress , growth response.