In vitro selection and genetic improvement of drought tolerance in cano- la (Brassica napus) using biochemical and molecular analyses

Abstract

Callus induction methods and plant regeneration system in six selected canola (Brassica napus) cultivars“Serw-4, Pactol, Sakha-1, Line-99, Line-162 and Line-123 grown under Egyptian environment were investigated for drought stress. Biochemical and molecular characterization were the other goal for this study. Hypocotyl explants (5-7 mm) from sterile canola seedling were cultured on MS media with different concentrations of plant growth regulators. The results of callus induction varied with respect to treatments and genotypes. For B. napus, the use of hypocotyl explants resulted in a higher percentage of callus formation, ranging from 46 to 100% on different media. Moreover, among six tested media, MS6 (MS + 0.1 mg/l NAA + 0.5 mg/l Kin) gave the best results on average of callus induction percentage with 100% of explants producing callus for cv. Serw-4, Pactol, Sakha-1, Line-99 and Lin-123. Meanwhile, Line-162 recorded 94% for callus induction. The lowest responses were noted for MS medium with 0.5 mg/l BAP + 0.5 mg/l Kin (MS5). Sakha-1 was the most responsive in terms of percentage of callus induction, while recorded 100 % on MS1, MS3, MS4 and MS6, 96 % on MS2 and 78 % on MS5. As well as the highest percentage of explants with shoot induction (58.84 %) and the highest number of shoot per explant (7) was recorded for this genotype. Assessment of isozyme banding patterns (esterase and peroxidase) to detect more genetic markers was also another attempt for this study. A total of 94 amplified fragments were generated by five random 10-mer primers, 78 polymorphic bands were detected in RAPD analysis, out of them, 18 were unique bands. These unique bands can be used as a specific marker for drought tolerance in canola.