Preharvest factors influencing superficial scald on 'Abate Fétel' pear: a three-year study with multivariate statistical approach

Although superficial scald (SS) is well characterized in apples, there are only few insights concerning the influence that orchard variability may have on its occurrence on pears. In this study we aimed to understand of the effect of preharvest factors on SS using a multivariate statistical approach. Pears (Pyrus communis L.) cultivar ‘Abate Fétel’ were picked during three consecutive seasons (2018, 2019 and 2020) from 23 commercial orchards in the Emilia Romagna region of Italy. Bioclimatic indices, agronomic management, orchard features and SS incidence were carried out at harvest and periodically postharvest in all producers stored in a regular atmosphere. In 2018 all the producers showed SS at the end of the storage, but in 2019 and 2020 some of them did not, up to 5 months. Nevertheless, in all growing seasons some factors can increase SS occurrence such as physiological and management factors: high yields, abundance of clay in soil, low watering frequency and improper nitrogen management, and use of plant growth regulators such as gibberellins. Other factors can decrease SS such as climate and agronomic factors: late harvest dates, precipitations, calcium and cow manure, presence of anti-hail nets, coastal weather and soil conditions, orchard age and canopy volume in relation with training system and rootstock. Initial preharvest variability is an important factor that modulates physiological plant stress and, subsequently, the SS after cold storage in ‘Abate Fétel’ pears. Multivariate techniques could represent useful tools to identify reliable multi-year pre-harvest variables for SS control in pear fruit different batches.