Effects of foliar applied zinc in the form of ZnSO₄ and Zn-amino acid complexes on pistachio nut yield and quality

Abstract

Despite the importance of Zn nutrition, little information is available on the effectiveness of foliar Zn application, in general, and Zn-amino acid complexes in particular on pistachio nut yield and quality. Response of pistachio (Pistachio vera L. cv. Akbari) to foliar application of zinc (Zn) in the form of mineral (ZnSO₄) and complexed with methionine (ZnMet), lysine (ZnLys), and lysine plus methionine (ZnLysMet) was investigated. Lysine alone treatment was used to distinguish the effects of accompanying Lys. A control treatment with no amino acids and Zn was also used. The critical deficiency concentration of Zn in the leaf to achieve the highest 100-kernel mass was 37.6 mg kg⁻¹. Foliar application of Zn significantly increased leaf Zn concentration in comparison with control. In both years, foliar supply of Zn in the form of complexed with amino acids resulted in a significant increase of total nut yield, fresh mass of 100-nut, and spilled nuts. A significant decrease in the empty nuts was also observed by Zn application. The effectiveness of ZnMet in improving yield and quality attributes of pistachio was in general, higher than the other Zn sources.

Keywords:

• amino acid
• lysine
• methionine
• Pistachio vera
• zinc

Additional information

Funding

The investigation was financially supported by Iranian Knowledge-based Company of Zist Fanavaran Novin Qom.