Genetic homogeneity and high shoot proliferation in banana (Musa acuminata Colla) by altering medium thiamine level and sugar type

To enhance the multiplication rate in Musa acuminata Colla (banana; 'Grand Nain') organogenesis, higher amounts of thiamine along with different sugar types and concentrations were evaluated at the proliferation phase. Thiamine at 1, 10, 50, 100, and 200 mg L-1 was compared with 0.1 mg L-1 thiamine found in conventional Murashige and Skoog (MS) medium. Maximum proliferation of banana was induced with 100 mg L-1 thiamine. Additionally, 15, 30, and 45 g L-1 sucrose, glucose, fructose, and sorbitol combined with regular and optimal levels of thiamine were tested. Glucose at 30 g L-1 most improved shoot proliferation alone and enhanced shoot proliferation further, when combined with 100 mg L-1 thiamine, followed by sucrose and fructose, whereas sorbitol completely inhibited growth and caused tissue browning. All evaluated vegetative traits were significantly affected by sugar type and concentration, and thiamine levels, unlike the photosynthetic pigments. Moreover, genetic stability of the plants recovered from the enhanced protocol was confirmed by inter-simple sequence repeats (ISSR) and randomly amplified polymorphic DNA (RAPD) analysis. A total of 230 bands generated by both marker types were monomorphic for the randomly selected regenerated plants, compared with their mother plant. Thus, the proliferation medium supplemented with 30 g L-1 glucose and 100 mg L-1 thiamine could be recommended for banana organogenesis. Results herein are of great importance and helpful in enhancing the commercial in vitro propagation protocols of banana, without the need of increasing the number of subcultures, which can cause somaclonal variation.