An instrument for measuring kiwifruit size

Abstract

An instrument designed for easy field measurements of kiwifruit volume or weight is described. Volume (or weight) calculated from a single length measurement has a resolution of ± 1 cm³ (g) permitting individual fruit growth to be monitored on a weekly basis. The assumption that the density of kiwifruit is 1 gm/cm³ is shown to be a very good approximation. Variations in fruit shape cause the average error in a single measurement to be 8%. Data collected are displayed with resolutions of 1 cm³ (g) for operator verification and are transferable to a portable personal computer to simplify data storage and analysis and to minimise handling errors. With this arrangement, a single operator can measure over 2 500 fruit in 4 h. The use of fruit growth information for assessing orchard practices such as irrigation management and for the early prediction of harvest fruit size in relation to target yield is discussed.

Keywords:

• fruit volume
• fruit weight
• fruit size distribution
• yield prediction
• irrigation management
• Actinidia deliciosa
• kiwifruit