To assess IB development potential from high watercore incidence FEMA Forelle

High levels of watercore were detected in the 2016 season. The objectives were therefore:

• To determine if watercore from FEMA fruit will diminish to acceptable levels during 5 to 12 weeks cold storage.
• To determine if watercore from FEMA fruit will develop into internal browning during 5 to 12 weeks cold storage.
• To determine if carbon dioxide can be used to predict IB development during
• To provide guidance to quality standards should PPECB be faced with similar decisions regarding watercore versus internal breakdown.

To determine if watercore severity influences sorbitol reabsorption by the fruit and IB development

Three populations of FEMA Forelle were identified as high watercore incidence fruit and sourced at CFG. One population came directly from the orchard and was subjected to a standard 600 ppb SmartFresh^SM application at the ExperiCo facilities. The other two populations were already subjected to a commercial SmartFresh^SM application.

Fruit were subjected to 50% CO₂ at ambient for 3 days after sourcing as means of internal browning prediction.

Fruit were evaluated after an immediate shelf life for 7 days and 5, 8 and 12 weeks storage followed by 7 days at 20 °C.

Fruit maturity data indicated that fruit were within FEMA standards regarding flesh firmness and TSS levels.

The CO₂ prediction test did not yield any internal browning development, even after 3 days.

Watercore was detected in low quantities, the highest being 5.3% in one population at time of sourcing. This particular population had lower incidence of watercore after cold storage and shelf life, but increased levels of internal browning after 8 and 12 weeks storage (5.7% and 3.7% respectively). Untreated control fruit had 4.1% watercore incidence after 12 weeks cold storage and 5.3% internal browning after 5 weeks cold storage. This suggests that fruit with watercore may be at a higher risk of exhibiting internal browning the longer the fruit are stored.

Watercore incidence was at such a low level at time of maturity measurements from these orchards historically prone to watercore, that no set conclusion can be drawn if cold storage can cause watercore to disappear, or whether high incidence of watercore increases the risk of internal browning. Internal browning did develop (3.7% – 5.7%) in fruit that had 5.3% watercore incidence at the start of the trial suggesting that this may well be the case. Preliminary results also noted a decrease in watercore with increasing cold storage.

Results need to be validated over a further season. Without a high incidence of watercore, it is difficult to see clear trends and make accurate conclusions