Development of best practice pre-and post-harvest protocols for production of Calypso mango - phase 2 (MG06005)

This is a final research report from Hort Innovation’s historical archives. Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.

What was it all about?

Calypso™ was a new mango variety bred in Queensland and began being commercialised in Australia with production established in the Northern Territory, Western Australia, Queensland and New South Wales. The objective of the project was to establish best production and postharvest protocols for Calypso™ across diverse environments using a “paddock to plate” supply chain focus to sustainably deliver a consistent high quality product to Australian and international consumers. Some agronomic and postharvest issues were addressed in an earlier R&D project (FR02049) on Calypso™ and were reported elsewhere.

Manipulation of flowering to improve the reliability of cropping and to advance fruit maturity was studied along with the impact of pruning on external fruit colour and yield. In orchards near Darwin, autumn-applied trunk scoring and Ethrel advanced fruit maturity, increased yield and significantly increased grower returns. Post wet season internal pruning of mature trees significantly increased the percentage of red blush on fruit without reducing crop yield. The length of the harvest window was defined during the 2008/09 season and found to be about two weeks in Darwin and Katherine, and three weeks for Bundaberg. This was shorter than expected and may have been influenced by season.

Further research was carried out to confirm fruit maturity to optimise ripe fruit flavour and standards set using flesh dry matter (14 per cent), average flesh colour (7) and heat accumulation units (1640 degree days). Near infrared spectroscopy (NIRS) was developed for rapid, non-destructive measurement of fruit maturity on the tree and became an important commercial tool to determine when to harvest.

Fruit ripening protocols were previously developed, but commercial recommendations were required to ensure fruit was dispatched to the retail stores at the correct ripeness stage. Dispatched when the fruit had just reached full yellow colour allowed fruit to arrive on the shelf with good flavour, and allowed adequate shelf life. A skin colour chart had been developed to assist the ripeners.

Further studies were carried out to minimise damage to the fruit skin through the harvesting and postharvest processes. The performance of harvest aids responsible for harvesting the bulk of Calypso™ crop were evaluated and recommendations to reduce skin damage made to the appropriate companies. Impact damaged during transport and packing were assessed and recommendations made to minimise the effect on fruit. Several alternatives for postharvest fruit disease control were evaluated and recommendations made for improvements included changes to temperature protocols that delivered the required specification to fruit to prevent postharvest rots. Retail fruit quality was monitored at store level, resulting in changes to the supply chain into the Northern Territory that delivered a significant improvement in on-shelf product quality.

Postharvest cool storage, controlled atmosphere (CA) storage and the use of SmartFreshSM as tools to prolong transportation life and optimise fruit quality were investigated. In addition, modified atmosphere (MA) created by a semi-permeable film and skin coatings were researched for possible beneficial effects on postharvest fruit quality. Protocols were developed for postharvest storage regimes, with 12°C giving the best result. There were add-on benefits from CA but little value from MA or skin coatings. Protocols were developed for vapour heat treatment to meet the access requirements for the Japanese market. These were lodged with Biosecurity Australia. Irradiation was investigated as a disinfestation procedure, but further research was required to develop a commercially acceptable result.

The R&D program had made a significant contribution to the commercialisation of Calypso™ mango in Australia. Since the start of the commercialisation of Calypso™, annual production had grown to approximately 4,500 tonnes and was expected to reach 25,000 tonnes by the time orchards mature. Results from agronomic and postharvest research have been disseminated through meetings, newsletters and field days and have been readily implemented by all Calypso™ stakeholders. Future R&D needed to focus on external fruit quality issues, fruit disinfestation (irradiation) for market access and market (domestic and export) development.