STUDIES ON BIO-HARDENING IN TISSUE CULTURE PROPAGATED BANANA PLANTLETS
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Date
2018-07
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University of Horticultural Sciences, Bagalkot
Abstract
Micropropagated plants experience high mortality during laboratory to land
transfer. Inorder to improve growth and reduce mortality at this stage, bio-hardening
holds great promise. Two banana cultivars namely Rajapuri Bale and Ney Poovan
were treated with different combinations of bioagents viz., Azospirillum lipoferum,
Bacillus megaterium, Trichoderma harzianum, Pseudomonas fluorescens and VAM
during primary and secondary hardening. There were eighteen treatment combinations
of which the first nine treatments were imposed to Rajapuri cultivar and the remaining
to Ney Poovan cultivar during primary hardening. The best four treatments of each of
the cultivars from primary hardening were carried forward for secondary hardening
with and without further augmentation.
Among the different bioagent treatments, the best four treatments from
primary hardening in Rajapuri Bale were combinations of A. lipoferum + VAM,
A. lipoferum + B. megaterium, A. lipoferum + T. harzianum and A. lipoferum +
B. megaterium + T. harzianum. Whereas, in Ney Poovan the best treatments were
A. lipoferum + B. megaterium, A. lipoferum + T. harzianum, A. lipoferum +
B. megaterium + T. harzianum and A. lipoferum + B. megaterium + P. fluorescens
(All bioagents were used at 1 g/pla nlets, except VAM 2 g/plantlets). For secondary
hardening, four best treatments were carried forward as such from primary hardening
and the remaining four were further augmented with bioagents during secondary
hardening (2 g each, except VAM 5 g). In addition to the growth parameters, major
nutrient concentration, microbial count and VAM colonization were recorded.
The results of secondary hardening revealed that the combinations of
A. lipoferum 2 g/plantlet + VAM 5 g/plantlet and A. lipoferum 2 g/plantlet +
B. megaterium 2 g/plantlet + T. harzianum 2 g/plantlet in Rajapuri Bale was found to
be the best treatment. Whereas, in Ney Poovan cultivar combination of A. lipoferum
2 g/plantlet + B. megaterium 2 g/plantlet + T. harzianum 2 g/plantlet and A. lipoferum
2 g/plantlet + B. megaterium 2 g/plantlet + P. fluorescens 2 g/plantlet was recorded to
be the best among the treatments in improving the growth and nutrient concentration.
It is evident that the growth and nutrient uptake can be improved in both the cultivars
using A. lipoferum and T. harzianum (1 g each/plantlet) during primary hardening and
further augmentation with A. lipoferum + B. megaterium + T. harzianum
(2 g each/plantlet) during secondary hardening.