The Effects of Deficit Irrigation on the Early Splitting of Pistachio Nuts and Aflatoxin Contamination

Background: The cracking of pistachio nuts is the major source of mold contamination as well as pests and aflatoxins.Materials and methods: The effects of deficit irrigation on pistachio-nut cracking were evaluated at two irrigation intervals(۲۵ days and ۴۵ days) and five omissions of the irrigation time. The frequencies of hull early splitting and cracking weredetermined in nuts.Results: All and all, long irrigation intervals and deficit irrigation since late April until early June were critical andincreased the early splitting rate (up to ۹۰%) in comparison with regular irrigation. The highest frequencies of the earlysplitting of pistachios were observed due to the drought stress at early June ranging from ۷.۷ percent to ۹.۶ percent. Deficitirrigation in July increased the rate of pistachio hull cracking significantly. The averages of the hull early splitting andcracking formation were by ۳۷ percent and ۱۸.۵ percent higher in ۴۵ days of irrigation intervals compared with ۲۵ days,respectively. The contents of B۱ and B۲ aflatoxins in hull early splitting and cracking were ۲۲۳.۴ µg.kg-۱ and ۲۵.۴۷ µg.kg-۱,respectively. In hull cracking fruits, aflatoxin B۱ and B۲ were ۱۱۱.۰۶ µg.kg-۱ and ۹.۷۱ µg.kg-۱, respectively.Conclusion: In general, to reduce the risks of aflatoxins in pistachio nuts, it is critical to manage irrigation in April andJune.

Keywords:

Aflatoxin , Aspergillus , Mycotoxins , Pistachio health