Abstract:
Induced mutation in conjunction with in-vitro culture increases the
effectiveness of mutation induction through handling large populations. It
facilitates in-vitro screening conditions against targeted disease and rapid
multiplication of selected variants. Koilkuttu (silk banana (AAB) which
demands high price in the local market is highly susceptible to fusarium wilt
caused by soil borne pathogen Fusarium oxysporum f.sp. cubense (Foc). In the
present study, in-vitro proliferated shoot tips of Kolikuttu banana variety
‘Agra’ were treated with ethyl methanesulfonate (EMS) aiming to develop
plants resistance/less susceptible to fusarium wilt. The EMS treated shoot tips
were multiplied for subsequent 3 subculture cycles and rooted in-vitro. A total
of 320 numbers of plantlets cultured in ½ strength Murashige and Skoog
(1962) medium were used for the co-cultivation technique. Each culture with a
rooted plantlet was inoculated with a piece of filter paper soaked in a 1x106
spores/ml suspension of the pathogen and incubated at 25±20C temperature,
12/12 day/night photoperiod with 50μmolm-2s-1 light intensity for 4 weeks.
The survived plantlets (2%) were potted in sterilized coir dust:sand (3:1 ratio)
medium and were hardened inside a propagator. After 3 weeks, plantlets were
shifted to a polytunnel. The remaining plants were then subjected to further
screening on a pathogen inoculated soil mixture. From the in-vitro survived
plants, 5 nos. of plants were infected with Foc at later screening stages.
Randomly Amplified Polymorphic DNA (RAPD) was performed for the two
plants survived along with a positive control. According to the dendrogram the
similarity of these 2 plants with the control (untreated Agra) was above
66.67%. Results of the present study confirmed the necessity of further
screening of survived plants in-vitro.
