Vascular flow of water induces side cracking in sweet cherry (Prunus avium L.)

This study has shown that rain induced cracking in sweet cherries occurs in two broad categories induced by different modes of water entry into the fruit. A rapid influx of water into the fruit via the vascular system was observed following natural rainfall. In field trials over three seasons application of excess (above routine irrigation) water to the root-zone, without wetting the canopy, induced large, deep cracks in the side of the fruit. Application of water at a similar rate to the canopy, but excluded from the roots by plastic mulch, resulted in a significant increase in small circular or semi-circular cuticular cracks localised around the stem and apex of the fruit, but did not increase the incidence of large side cracks. In a separate trial removing leaves prior to a natural rainfall event resulted in a significant decrease in side cracks and a significant increase in cuticular cracks around the apex compared with an untreated control. Retaining the leaves, but tying them back to expose fruit resulted in significantly lower levels of side cracks, and higher levels of cuticular cracks. The results from these trials suggest different water uptake mechanisms for the development of side cracks and cuticular cracks