The trial block of the top 20 selections has been nurse-suckered and prepared for rating the susceptibility of the variants to yellow Sigatoka in the coming months.
Later this year, the plan is to establish two on-farm trials (with around 50 plants of each selection per site) to evaluate how these variants grow on a larger scale under commercial farming practices. In the process, larger volumes of fruit will become available to fine-tune the harvesting criteria and post-harvesting handling requirements, ensuring optimal fruit quality and eating experience for the consumer.
We also plan to screen the remainder of the top five variants in the Northern Territory to confirm they have retained their TR4 resistance. Variants 544 and 144 have already been screened in a plant crop, where they were rated as being resistant and highly resistant respectively to TR4 – see Australian Bananas Issue 65, August 2022, pp.18-19.
The banana freckle outbreak in the NT has contributed to delays for continuing this necessary trial work, which is now part of the project BA21002: ‘New varieties for Australian banana growers’.
Goldfinger (FHIA-01) which was bred by the Honduran Foundation for Agricultural Research (FHIA) is a non-Cavendish dessert banana variety that is highly resistant to Panama disease tropical race 4.
Variety evaluation work previously conducted at South Johnstone has shown the agronomic performance of Goldfinger rates relatively well when compared to Williams. Average bunch weight of plant crop was heavier for Goldfinger at 34.3 kg compared to Williams 30.5 kg. However, the variety had a longer cycling time at 14.4 months from planting to harvest, compared to 12.4 months for Williams. Although it is a reasonably productive variety, improvements are sought in fruit quality characteristics.
Mutagenesis was the technique used to induce change to Goldfinger tissue culture material with the aim of improving fruit quality characteristics, whilst maintaining high resistance to TR4.
Mutagenesis, which is a breeding technique using gamma irradiation to promote changes in tissue cultured plants, has been applied to the cultivar Goldfinger. The aim is to develop an improved variety which retains its tolerance to the disease and has improved fruit quality 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 Goldfinger was determined.
This project has made selections from the original 630 irradiated Goldfinger plants based on agronomic and post-harvest characteristics. Further taste-testing identified five variants to include in a large-scale consumer and sensory evaluation. Click on the menu below for more information on the screening process.
630 irradiated Goldfinger plants were sent to South Johnstone Research Station, in two batches during June and August 2017 where they were held in the glasshouse prior to planting. Click here for more information.
Following the selection of the top 20 variants from the original 631 plants, sucker and bit material from the original trial was planted in September and October 2019. Click here for more information.
Plants of the top 20 selections were nurse-suckered in December 2020 and the first bunches began emerging in June 2021. Agronomic data has been collected from all variants, but only fruit from the top five performers was sent down for consumer and sensory evaluation at DAF’s Coopers Plains facility in Brisbane. Variants 144, 211, 521, 544 and 903 were the top five tasting selections chosen to be further assessed in the larger consumer surveys. Click here for more information.