Developing resistant varieties
Dwarf Nathan mutagenesis trial

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In December 2017, 309 plants were planted into the field inoculated with Panama disease tropical race 4. Cavendish and Dwarf Nathan plants which hadn’t been irradiated were also planted as control plants to compare against.

Dwarf Nathan mutagenesis trial at Coastal Plains Research Farm.

Dwarf Nathan overview

Dwarf Nathan is a naturally selected Extra Dwarf Cavendish originally from Israel. It was imported into Australia in the mid 1990s. The variety was included in the most recent Panama disease tropical race 4 (TR4) variety screening trial in the Northern Territory. While it showed relatively high resistance to TR4 in this trial, it did not possess commercially acceptable agronomic characteristics and as a result was selected for mutagenesis. 

Trial progress

Mutagenesis, which is a breeding technique using gamma irradiation to increase changes in tissue cultured plants, has been applied to cultivar Dwarf Nathan. The aim is to find an improved variety which retains its tolerance to the disease and has improved agronomic characteristics. 
The first step in this process was to determine how much gamma irradiation to use on this variety. Too much irradiation can severely damage or kill the plant, and too little may not induce sufficient changes to the plants. 
Experiments, known as dose response trials, have been conducted at the Maroochy Research Station and the sufficient dosage for Dwarf Nathan was determined. 

Dwarf Nathan were irradiated and sent to the Northern Territory, where they were held in the nursery prior to planting.
309 plants were planted into the field (inoculated with TR4) in December 2017. Cavendish and Dwarf Nathan plants which hadn’t been irradiated were also planted as control plants to compare against. 

Example of tissue culture that undergoes gamma irradiation treatment.
Gammacell chamber used to apply gamma irradiation to banana tissue culture.
Mutagenesis trial - irradiated Dwarf Nathan plants showing variation as a result of mutagenesis.
Variety screening trial - Dwarf Nathan plant crop.
Mutagenesis trial - control plants of Dwarf Nathan and Williams.

Check back on this page for progress updates on this trial.

This trial is part of the Fusarium Wilt Tropical Race 4 Research Program (BA14014) which has been funded by Hort Innovation, co-investment from the Queensland Department of Agriculture and Fisheries, and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.