چكيده لاتين :
Date bunch fading disorder is one of the most important problems of Iranian date growers in recent years. In order to determine the probable role of air temperature and relative humidity in July to September on disorder incidence and development, a thermometer and hygrometer were set up in a ʹMazaftiʹ date orchard in Jiroft area during 2002-2004. Data were recorded 10 days before disorder appearing to harvesting time. Samples were taken from 20 trees 15-17 years old with 5-6 days interval for determining the rate of real damage percent. Thirty-six parameters of RH and temperature were extracted from the hygrograph and thermograph and simple correlation was done between them and real damage percentage. Based on the results, the disorder was appeared on 20, 29 and 28 July 2002, 2003 and 2004, respectively. The average of real damage percentage was determined 52/66 percents in the mentioned years. In ʹMazafatiʹ cultivar, the disorder was appeared at temperatures above 43 °C and relative humidity below 25% when the fruits were changing from Khalal to Rotab stage. Among 36 meterological parameters, two parameters including Tmax, (Mean of the maximum temperature between 10 AM to 16 PM in each period) and d (Mean of the total hours which relative humidity was between 25%-50%) showed the highest correlation with the real damage percentage. Correlation coefficients for the TmaX] were found 0.50 in 2002, 0.85 in 2003 and 0.69 in 2004 and for d were 0.78 in 2002 , 0.60 in 2003 and 0.59 in 2004, respectively.
