ارتباط بین تاریخ تشکیل پسته های زودخندان و تغییر در خصوصیات ظاهری و آلودگی آنها به آفلاتوکسین در سه رقم پسته تجاری ایران (اوحدی، کله قوچی و احمد آقایی)

Early splitting in pistachio is one of the most important contaminant factors which affect on yield in orchard. Knew of the time of pistachio early splitting occurrence in orchard and also their physical & external characteristics in identification and omitting of them are important factors in processing stage. In this research the time of early splitting occurrence in three commercial cultivars of pistachio including "Ohadi", "Kalehgoochi" and "Ahmadaghaei" in two different areas were evaluated. Their physical characteristics such as: Fruit fresh weight with hull, Fruit fresh weight without hull, Fruit dry weight without hull, Percentage of fruit humidity without hull, Fresh weight of hull, Dry weight of hull, Percentage of hull humidity, Length of early splitted fruit, Width of early splitted fruit and Diameter of early splitted fruit were measured. Also, percentage of their contamination to fungus group of Aspergillus flavus and A. niger, percentage of stains on the shell and percentage of insects' infestation were measured. The time of early splitting occurrence in different years, areas and cultivars showed high changes and early splitting in "Kalehghoochi" occurred earlier than others. The highest percentage of early splitting occurred 15 days before harvest time. Percentage of fruit humidity without hull and percentage of hull humidity in early splitted fruits with soft and smooth hull were about 27 and 65, furthermore, in early splitted fruits with semi-dry hull were about 22 and 50 and in early splitted fruits with dry hull were about 14 and 31, respectively. Weight, length, width and diameter of dry nuts in early splitted fruits with soft and smooth hull were higher than early splitted fruits with semi-dry and dry hull. Results indicated that percentage of contamination of early splitted fruits with fresh, semi-dry and dry hulls to Aspergillus fungus reduced and percentage of contaminated fruits hull which their hull splitted during mid- July to end of July were higher than those splitted during mid-August to end of August. There was a direct correlation between time of splitting and percentage of stains on the shell, as in fruits which early splitting occurred earlier, the percentage of stains on the shell were higher. In this research, the relationship between infested fruits to carob moth and increase of contaminated fruits to Aspergillus fungus was observed. The measurement of aflatoxin content revealed that the early splitted fruits with dry hull containing the highest aflatoxin content and showed significant differences in compare to early splitted fruits with soft and smooth hull. The content of aflatoxin was highest in kernel and nil in hull.