On-tree maturity control of peach cultivars: Comparison between destructive and nondestructive harvest indices

Abstract

Optimal harvest maturity is required for flavorful peach. The supply chain often errs on the side of immature fruit with subsequent consumer dissatisfaction. Maturity indices used to determine harvest date of peach include nondestructive assessments of size and background color, and destructive measurements of flesh color, firmness and soluble solids content (SSC) . More recently an index related to the absorbance of chlorophyll (IAD) can be nondestructively assessed with a DA-meter. This application is particularly useful in red-skinned cultivars in which background color changes from green to yellow are not perceptible to the naked eye. The objective and nondestructive IAD was compared with objective and destructive assessments of firmness and SSC, as indices to make harvest decisions on peach orchards. Seven peach and five nectarine cultivars [Prunus persica (L.) Batsch] were studied. Fruits were assessed with a DA-meter and the resulting IAD values were related to firmness and SSC in several consecutive samplings during the maturity period for each cultivar. Pooling all sampling dates for each cultivar, significant positive linear regressions were observed between IAD and firmness, with coefficients of determination 0.11<R2<0.65. However, in each cultivar the linear regression parameters between IAD and firmness are different and changed in sequential samplings required for maturity control and in successive harvests. No significant relationship was observed between IAD and SSC in any cultivar. In conclusion, the DA-meter cannot replace firmness and SSC measurements during on-tree maturity control, which remain essential for sensory quality management in the supply chain. .