Biohardening of Tissue Cultured Banana Plantlets of cv. Ney Poovan for the Management of Fusarium wilt of Banana with Bacillus amyloliquefaciens (VB7) Triggers Defence Gene Products and Growth Promotion

Fusarium wilt of banana is the most devastating disease caused by Fusarium oxysporum f.sp. cubense (Foc). In order to combat the early onset of Fusarium wilt disease, an experiment was carried out on biohardening of tissue cultured plantlets. Six bacterial endophytes were observed to inhibit the growth of Foc in vitro. Among the six bacterial endophytes, Bacillus amyloliquefaciens (VB7) inhibited mycelial growth of Foc to an extent of 70.58% over control. Further, these bacterial endophytes were used for biohardening of the tissue cultured banana plantlets cv. Ney Poovan (AB) during primary and secondary hardening stages. Among the bacterial endophytes, B. amyloliquefaciens was found to significantly enhance plant height, leaf production, root numbers and root length compared to untreated control. Activity of defense enzymes were also enhanced and such increase in activity was observed to be to an extent of 93.67% in peroxidase, 92.39% polyphenol oxidase, 97.60% phenylalanine ammonia lyase and 26.23% in β-1, 3-glucanase defence enzymes in plants biohardened with B. amyloliquefaciens (VB7) over untreated control after inoculation of Foc. Tissue cultured plants of Ney Poovan biohardened with B. amyloliquefaciens (VB7), B. paraconglomeratum (YEB PT2) and S. maltophilia (YEB RH2) were completely free from wilt incidence symptoms upto planting stage when challenged with Foc inoculum under pot culture conditions. As among these three endophytes, B. amyloliquefaciens (VB7) also influenced favourable growth promotion, it can serve as a potential biocontrol agent for management of Fusarium wilt of banana.

Shelf Life Extension of Banana (Musa spp.) using Hexanal Formulation as a Post-harvest Dip

Postharvest dipping of fruits in hexanal formulation extends the shelf life by inhibiting enzyme phospholipase D (PLD) activity. To enhance the postharvest shelf-life and quality of different banana cultivars viz., Grand Naine (AAA), Ney Poovan (AB), Poovan (AAB) and Rasthali (AAB) were treated with different concentration of hexanal formulations (1% and 2% Enhanced fresh formulation (EFF)) and stored at atmospheric storage condition. The results indicate that the quality characteristics of 2% EFF treated fruits of Grand Naine (AAA), Poovan (AAB) and Rasthali (AAB) were low TSS, total sugars, reducing sugars and acidity indicating the perpetuation in quality of fruits during storage life besides extended shelf life of fruits. Banana fruits treated with hexanal, irrespective of cultivars experienced a significant delay in weight loss and higher firmness as compared to respective control. The high-resolution imaging had clearly shown that the application of hexanal delayed the ripening process by the structural integrity of cells on skin and fruit pulp. The PLD enzyme activity, respiration and ethylene evolution rates (more than 10%) were markedly reduced over control due to hexanal treatment. Our results revealed that the application of hexanal formulation as postharvest dip treatment in different banana cultivars significantly enhanced shelf life over control besides continuance of quality during the storage period.