Changes in anthocyanin synthesis as an index of maturity in red apple varieties

Changes in the regulation of anthocyanin accumulation may be useful for predicting maturity in Jonathan and other early to mid-season, red apple varieties. While the level of anthocyanin at a particular stage of maturity may be related to environmental factors, the capacity to accumulate anthocyanin is a function of maturity and independent of environmental influence.

Anthocyanin is degraded in immature fruit skin as rapidly as it is formed, giving an equilibrium level that is a function of the light intensity. When light intensity is reduced (by shading), the anthocyanin level falls in immature fruit skin but continues to rise in mature fruit skin. The transition from the immature to mature stages with respect to anthocyanin accumulation occurs rapidly and precedes the normal harvest date by about two to three weeks, suggesting that this attribute might be used in the prediction of maturity in suitable red apple varieties.