In vitro mutation studies in native varieties of banana

Banana is the second largest fruit crop and fourth most important commodity at global level next to rice, wheat and dairy products. Banana cultivation is limited by Fusarium wilt, sigatoka and nematodes. Conventional breeding methods have been of limited success due to parthenocarpy, polyploidy and sterility. Studies on in vitro mutagenesis in Banana were therefore, carried out at Department of Crop Improvement and Biotechnology, KRCCH, Arabhavi, during the year 20122013. Three native varieties of banana were used for the experiment, namely Rajapuri bale, Yelakki bale, Nanjangudu rasbale (all AAB genomic group). The shoot tips were used as explant for establishing aseptic cultures. Aseptic multiple bud cultures were irradiated with different doses of gamma rays (25,35,45,55 and 65 Gy) using ⁶⁰Co source at BARC, Mumbai. Among the different doses of gamma irradiation maximum survival and regeneration was recorded at 25Gy (53.33%; 45.00%) as compared to un-irradiated control (94.66%; 91.66%, respectively). There was reduction in culture growth with increase in doses of irradiation. Growth was better at lower doses of gamma irradiation as compared to higher doses. The putative mutants viz., dwarf mutants at 55 and 65 Gy, mini dwarf mutant at 65 Gy and chlorophyll mutants at 35,45,55 and 65 Gy were observed after hardening. These mutants are further being field evaluated to identify and select mutants showing desirable traits.