Genotypic differences in sweet cherries are associated with the susceptibility to mechanical damage

- Susceptibility to mechanical damage (pitting) was described for sweet cherry cultivars.
- Structural and rheological properties of the fruit tissue are related to fruit damage.
- External mesocarp cell numbers are positively associated with mechanical damage.
- Large mesocarp cells are related to high values of rheological properties.
- High values of stress and strain are required for less susceptible fruit.

The rheological properties and structure of the flesh tissue at harvest-ripe fruit of the sweet cherry Prunus avium L. cultivars Bing, Lapins, Regina, Santina, Sweetheart and Van were measured using a textural analyzer equipment and described by light microscopy, respectively. The rheological measurements inflicted reproducible levels of mechanical damage (pitting). The structural and rheological properties of the mesocarp and epidermis correlate with their susceptibility to mechanical damage. Epidermal cell width and area of external mesocarp cells were negatively associated with susceptibility to mechanical damage while cell number, quantified in 1 mm2 of external mesocarp, was positively associated. Fruit of Bing and Regina are the least susceptible to mechanical damage among the cultivars under study. The least sensitivity of Regina fruit was associated with its wide epidermal cells and high value of modulus of elasticity, while in Bing with its low number of cells as well as high values of stress and strain at bioyield point. The high susceptibility to mechanical damage of Sweetheart and Lapins fruit was associated with their large number of cells in the external mesocarp tissue and with the lowest values of strain at bioyield point, therefore with the lowest deformation capacity of the tissue.