Preconditioning and Fruit Maturity Interactions On Soft Scald and Soggy Breakdown of ‘Honeycrisp' Apples

‘Honeycrisp’ apples were harvested at starch indices of 2 to 4 and 5 to 7 from two orchards in 2008 and 2009.  Fruit were harvested on two different dates to get fruit at different stages of maturity in 2008.  In 2009, ethephon was applied to trees to get fruit at two different stages of maturity on the same date.  Fruit were preconditioned at 16 to 22 ºC for 7 days and then put in cold storage at 1 ºC with unconditioned fruit until Dec. 2008 or Jan. 2009.  With the early stage of maturity in 2008, preconditioning did not reduce soft scald incidence (SSI) which was 22% in fruit from Orchard 1 and 2% from Orchard 2.  SSI in fruit from Orchard 1 with the later fruit maturity was 35% and this was reduced to 1% by preconditioning.  SSI remained low in fruit from Orchard 2 with the later maturity. In 2008, soggy breakdown incidence (SBI) was 2% in the unconditioned fruit and was increased to 16% by preconditioning with fruit at the earlier stage of maturity with both orchards.  With later maturity, SBI was similarly increased by preconditioning in fruit from Orchard 2, but not with Orchard 1 which had very low incidence, <1%.  In 2009, very little soft scald or soggy breakdown, <2%, occurred with either stage of maturity in unconditioned fruit.  SSI and SBI were increased to 8% and 5% respectively, by preconditioning fruit at the earlier stage of maturity, but not the later stage and only in fruit from Orchard 1.  SSI and SBI in fruit from Orchard 2 was unaffected by preconditioning.  In some cases, preconditioning ‘Honeycrisp’ apples at an early stage of maturity increased incidence of soft scald and soggy breakdown.