MSc

Tissue culture banana plants have become an integral part of commercial
banana production. Banana micropropagation is hampered by high unit cost of
production, poor multiplication and low survival rates during acclimatization. To
make a commercial micropropagation unit viable, cost of production of plantlets
should be brought to minimum.
The
investigations
on
‘Low
cost
alternatives
in
commercial
micropropagation of banana’ was hence taken up at Centre for Plant
Biotechnology and Molecular Biology, College of Horticulture from 2016-2018.
The aim of the investigations was to reduce the cost of production in commercial
micropropagation of banana. Studies were conducted in different cultivars like
Attunendran (AAB), Nedunendran (AAB), Chengalikodan (AAB), Poovan
(AAB), Njalipoovan (AB) and Grand Naine (AAA) which were commercially
produced at CPBMB in the micropropagation unit. Established cultures of six
cultivars in the 5th subculture cycle received from the commercial
micropropagation of
unit
CPBMB
were
utilized
for
the
study.
The
micropropagation protocols optimized for the six different cultivars at CPBMB
were followed for production of plantlets. The clonal fidelity analysis
standardized using specific ISSR marker at CPBMB was used to analyse the
clonal fidelity of regenerants from S7 to S11 stage.
Sucrose was substituted with common sugar @ 30gL-1
in MS
multiplication and rooting media and shoot proliferation, rooting and root
characters in different cultivars were studied. Common sugar was found equally
good to sucrose and it did not influence shoot proliferation in different banana
cultivars. Common sugar was also found equally good to sucrose in the rooting
media recording 100 per cent rooting in all the six cultivars studied. Substitution
of sucrose with common sugar had no significant influence in the days taken for
root initials to appear. For number of primary roots produced, there was no
significant difference in all the cultivars in the two media except Attunendran in
which medium with common sugar produced more number of primary roots
(8.41) than sucrose (6.75). Root length was higher in MS rooting medium with
common sugar in cultivars like Chengalikodan, Njalipoovan and Grand Naine.
Medium with common sugar produced more number of secondary roots in
cultivar Chengalikodan while medium with sucrose produced more number of
secondary roots in cultivars like Attunendran and Njalipoovan.
When fifty per cent of agar was substituted with other solidifying agents
like sago or isabgol, there was good solidification of MS medium. There was no
significant variation in shoot proliferation in different cultivars when half of agar
was substituted with isabgol or sago in the MS multiplication medium. Fifty per
cent substitution of agar with isabgol or sago was found equally good to agar
(100%) in rooting medium. Hundred per cent rooting was observed in the three
different media combinations in all the cultivars. Substitution of 50 per cent agar
with isabgol or sago showed no significant difference in days taken for root
initials to appear, number of primary roots, number of secondary roots and root
length in cultivars like Attunendran, Njalipoovan and Grand Naine. There was no
difference in survival of plantlets in treatments with different low cost additives.
When low cost carbon source and gelling materials were used instead of standard
additives, there was 87 per cent reduction in media cost.
Clonal fidelity was analysed using specific ISSR marker optimized at
CPBMB as reported by Rajitha et al.
(2015). Polymorphic amplicons were
observed as subculture progressed from S9 – S11 in cultivars like Nedunendran,
Attunendran and Grand Naine. In Chengalikodan, up to 10th subculture passage no
polymorphic bands were observed. In cultivars like Poovan and Njalipoovan
which exhibited low multiplication rate, no polymorphic bands were observed in
regenerants up to S11 stage.
For highly multiplying cultivars like Attunendran, Nedunendran and
Grand Naine subculturing for multiplication up to 8th subculture stage is
recommended. In Chengalikodan, subculturing for multiplication can be advanced
up to 9th subculture passage and in Poovan and Njalipoovan multiplication can be
advanced up to 10th subculture passage in the protocol standardized at CPBMB.
However, the commercial feasibility of the findings and working out the
economics of production is possible only by large scale adoption of media
components and subculture pattern in commercial micropropagation protocol.