First ratoon results - agronomic evaluation trial (October 2020)
By Katie Robertson & Jeff Daniells, Queensland Department of Primary Industries
Trends observed in the plant crop (see here) continued in the first ratoon. Williams outproduced the TR4 resistant Cavendish varieties. All the Lady Finger selections performed well compared to the standard Lady Finger, with either improved plant or bunch characteristics and no yield reduction.
Productivity declined in the short statured TR4 resistant Cavendish Asia Pacific #1, while GCTCV 106 continued to perform comparably to Williams.
The yield reduction measured in the plant crop of the TR4 resistant Cavendish variety Asia Pacific #1 (AP#1) was further amplified by the end of the first ratoon. AP#1 yielded 33% less than Williams over the 2 crops (29.3 versus 44.1 kg/year). This was due to their longer cycle time and a lower average bunch weight (26.7 versus 37.9 kg). AP#1 pseudostem height only increased by 8% between the plant crop and first ratoon (2.2 to 2.4 m), remaining significantly shorter than the other Cavendish varieties. Most other TR4 resistant Cavendish selections from Taiwan are taller than Williams. Finger length also remained shorter, with only 17% of AP#1 fruit falling into the premium size grade (22 – 26cm), compared to 56% for Williams. The GCTCV 106 selection – which originated from a vigorous plant identified in the previous 2018 South Johnstone variety evaluation (BA16001) – again performed comparably to Williams with regards to cycle time and yield (see table). Unfortunately, this variety has not demonstrated TR4 resistance in the Coastal Plains (Northern Territory) screening trials (see here for more).
There were no yield differences among the six Lady Finger varieties, with some selections displaying reduced pseudostem heights and better bunch conformation.
All Lady Finger selections, except Pendulous Lady Finger (PLF), remained significantly shorter in stature than standard Lady Finger in the first ratoon (11 – 30% shorter). In the plant crop, PLF had yielded 19% more than Lady Finger per 12-months, but by the end of the first ratoon the yields compared over the 2 crops was not different. The standard Lady Finger experienced a 33% increase in bunch weight between the plant crop and first ratoon, going from 12.2 to 18.5 kg, while PLF only had 15% heavier bunches in the first ratoon (17.7 to 20.9 kg). The fruit in PLF bunches took longer to fill (22.3 weeks) than standard Lady Finger (17.1 weeks), and had issues with premature ripening, likely influenced by the timing of bunch emergence and the environmental conditions during fruit filling. Nonetheless, the PLF plants lived up to their name and continued to produce bunches with a more desirable conformation. The four other Lady Finger varieties did not yield significantly differently to the industry standard.
The novel hybrids from CIRAD continued to perform poorly in the first ratoon, in terms of bunch size and pseudostem height.
In the plant crop, 40% of the CIRAD hybrid 918 plants had snapped before harvest despite being similar height to Williams. The incidence of pseudostem snapping in this variety rose to 87% in the first ratoon, meaning there were not enough data plants to include in the analysis. The remaining three CIRAD hybrids had bunch weights 25 – 64% lower than Williams per 12-months for the 2 crops, and CIRAD 925 and X17 were taller by 10 and 17%, respectively. X17 has demonstrated a high level of resistance to TR4 in the NT (see here for more).
Where to next?
The trial block was nurse suckered at the beginning of the year to manage the cropping cycle, and the varieties were rated for yellow Sigatoka over the wet season. These results will be reported on later in the year.
More information
This research has been funded as part of a project funded by Hort Innovation, using the banana research and development levy, co-investment from the Queensland Department of Primary Industries and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.
