`Bing' sweet cherry is the most widely planted cultivar grown in the Western US because of widespread market acceptance. High prices are associated with early maturing `Bings' so growers are inclined to plant in early maturing growing regions. High numbers of less marketable, abnormally shaped (deep sutures, spurs, doubles) fruit tend to be produced in these regions. It is thought that abnormal fruit development is associated with high summer temperatures. Dataloggers equipped with thermocouples were located in 7 California cherry growing regions. Thermocouples were positioned throughout tree canopies, monitoring flower bud temperatures for 2 seasons from May to October. A Richard's function was used to describe the relation of average daily temperature (July, August, September to the percentage of fruit with deep suture. Correlation coefficients (R2) of 0.85 and higher were found, with increases in average daily temperatures above 22C associated with the formation of abnormal fruit shapes. Heat lamps were used to increase spur temperatures 5-7C above ambient during the July through September period, High percentages of abnormal flowers were produced in the season after 2 July, but not after 21 August heating, Strategies to lower high summer canopy temperatures helped to reduce abnormal fruit shapes.
If the inline PDF is not rendering correctly, you can download the PDF file here.