In vitro SCREENING OF CACTUS [Opuntia ficus- indica (L.) Mill.] GENOTYPES FOR SALT TOLERANCE

Abstracts

Aim: The experiment was carried to study the performance of cactus genotypes for salt tolerance under in vitroconditions.

Study Design: The experiments were laid out in completely randomized (CRD) with three replications.

Place and Duration of Study: Mekelle Agricultural Research Center, Ethiopia during 2013/2014.

Methodology: Six genotypes namely Suluhna, Gerao, Lemats Beles, Keyih Beles, Limo and Shenkor were used for this study. Callus was initiated in MS medium 4 mg/l Dichlorophenyl Acetic Acid( 2,4- D ) + 0.5 mg/l 6- Benzyl Adenine (BA) and different concentration of Sodium chloride (NaCl) 0 mM, 50 mM, 100 mM, 150 mM and  200 mM were added to the medium to create salt stress.

Results: Data analysis revealed that all the genotypes and treatments and their interaction effect were significantly different from each other. The grown genotypes at different level of salinity showed significant variation on days required for callus induction.  Among the six genotypes plated at MS medium supplemented with 0 mM NaCl and 50 M NaCl, Suluhna was significantly superior for callus induction with 100% and 66.7%, respectively followed by Gerao (91.7%), Lemats Beles (91.7%). At MS medium supplemented with 50 mM NaCl, the highest callus fresh weight was recorded in Suluhna genotype 4.91 g and the least was in genotype Shenkor 3.52 g. When the callus for these genotypes were transferred to regeneration media in the same level of NaCl stress at 50 mM, the highest level of  shoot regeneration was observed in Suluhna ( 41.6%) followed by Gerao and Keyih Beles (33.3%). A decreasing pattern in number of shoot of the cactus genotypes were observed with increasing salinity levels, at MS medium supplemented with 50 mM NaCl from spineless genotype, Suluhna had also showed higher shoot number (7.0) and the lowest was recorded at Limo (3.0). Shoot number was adversely affected at 100 mM NaCl. In the proliferation culture media, shoot length was significantly affected by the NaCl treatments. The rooting parameters decreased significantly from 50mM NaCl and no rooting occurred when explants were grown with 100 mM NaCl.

Conclusion: All in vitro growing cactus genotypes were found to be sensitive in NaCl above 50 mM NaCl. This in vitroscreening technique with different concentration of NaCl stress could also be used as a good screening technique for salt tolerances rather than the field screening because of efficient cell line development and requires less time, space and labour.

Keywords :Callus induction; regeneration; sodium chloride.

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Posted July 7, 2018 06:30