Relationship between Fruit Maturity at Harvest and Fruit Quality in Peach

Determining the right time for harvesting peaches is of utmost importance to everyone in the fruit growing and distribution chain: growers, distributors and consumers. Peach maturity at harvest affects fruit quality and consequently consumer preference in the market. Fruit size and red skin coloration are the most common indicators of fruit maturity used to decide when to harvest in everyday orchard operations. These attributes can vary from year to year and do not provide fully reliable assessment of maturity especially in newly released cultivars with extensive red skin color. Fruit firmness (FF), soluble solids concentration (SSC) and/or total acidity (TA) are better indicators of fruit maturity. However, their simple and rapid assessment does not provide all necessary information and requires fruit destruction. A new, nondestructive, fruit ripening device, the DA meter, determines fruit ripeness by measuring the chlorophyll (I-AD index) in fruit, where I-AD decrease during the maturation of fruits from 2.0 to a 0.1. This is a promising tool for both practical and scientific applications, since it allows one to monitor on-tree fruit ripening, to establish accurately the optimal harvest time, and to reduce the variability that is present in fruit batches. In this research the DA meter was evaluated over three seasons in 10 peach cultivars grown and marketed in South Carolina for its ability to determine fruit maturity and correlate maturity index to ripening related changes in fruit quality parameters. Data revealed that few cultivars were harvested at the correct maturity. FF was positively correlated with maturity index, while SSC and TA showed no difference between fruit of different maturities. SSC/TA ratio, however, was negatively correlated with the fruit maturity index suggesting better taste of more mature fruit, I-AD <= 0.6, which was valued most by consumers.