What was it all about?

Australia has the world’s largest custard apple breeding program. The aim of this project was to accelerate industry development by identifying improved varieties and rootstocks, better crop management techniques, increased reliability of production, maintenance of minor use permits and extension activities.

This project supported an intensive breeding program focussed on the development of high yielding red skin varieties with excellent taste quality, destined for markets in Asia.

Varieties were grown and rated on a number of factors including tree shape, yield, fruit quality, and skin colour, as well as resistance to chilling injury and fruit rots. Researchers tested a number of pesticides for effectiveness on major pests, looked into hydrocooling of harvested fruit, and the effects of vertical and open V trellising methods.

Key findings included…

• A highly reliable clonal propagation technique was developed, which will greatly improve on the current system which produces genetic variation between trees
• Two new selections from the breeding program were released to industry for commercial testing
• High quality red-skinned selections were released for on-farm testing
• Elite selections were taste tested and compared with the industry standard KJ Pinks, revealing new flavours
• In a comparison of different rootstock species and varieties, moderately vigorous rootstocks produced higher yields
• Improved recommendations on how to manage trees on these various systems were incorporated into a tree training manual
• Minor use permits were obtained from APVMA for selected fungicides and pesticides, providing effective pest and disease management options for growers
• It is expected that high yielding trellis and mechanically pruned hedge row systems will be increasingly adopted.

The findings from the research were incorporated into a new version of grower manuals, and the team arranged field days and farm walks in the major custard apple growing regions.

This significant body of work produced a combination of new varieties, clonal rootstocks and training systems that will lead to greater profitability and reliability of custard apple production.