Granulation is a common maturity related physiological disorder of Navel and Valencia oranges of increasing importance in Chile. In order to stablish the effects of harvest date on orange fruit granulation during on tree storage, a study was carried out during two seasons ( 1997 and 1998), in four orchards in two growing areas in the Central Zone of Chile. In 1997, fruit was picked in each orchard from September to December and in 1998 was picked monthly from early August to late November.
In both seasons, three of the four orchards were affected by granulation at harvest. The incidence and severity of granulation in the orchards increased throughout the season. For Lane Late in 1997 season, the incidence of the disorder increased from 12% in early October to 75% in December. For Navelate, granulation was only present in one of the orchards, increasing from 38% in October to nearly 74% in November. In 1998 season, the disorder in Lane Late reached nearly 89% in November.
At harvest, a sustained increase in granulation was observed at the stem end, equatorial zone and stylar end of the fruit as the season progressed. In Lane Late, the incidence was higher at the stem end than the equatorial or stylar end. In Navelate the disorder was more evenly distributed from the stem-end through the stylar end of the fruit.