Document Type : Research Paper - Tropical and Subtropical Fruits

Authors

• Farzad Abdollahi ¹
• Abdolkarim Zarei ²
• Javad Erfani-Moghadam ³
• Mahmood Rostaminia ⁴

¹ Former M.Sc. Student, Department of Horticultural Sciences, Faculty of Agriculture, Ilam University, Ilam, Iran

² Associate Professor, Department of Plant Production and Genetic (Plant Biotechnology), Faculty of Agriculture, Jahrom University, Jahrom, Iran

³ Associate Professor, Department of Horticultural Sciences, Faculty of Agriculture, Ilam University, Ilam, Iran

⁴ Associate Professor, Department of Water and Soil Engineering, Faculty of Agriculture, Ilam University, Ilam, Iran

Abstract

Introduction
Pomegranate (Punica granatum L.) is a fruit-bearing species with a long history of cultivation in the tropical and subtropical regions of the world. Pomegranate production in Iran, as the main pomegranate producer in the world, is faced with different challenges. Fruit cracking is one of the serious disorders in pomegranate that cause significant reduction in the quality of fruit and subsequent economic damages to the pomegranate producers annually. Fruit cracking can be controlled to some extent by appropriate orchard management. Proper orchard fertilization is among the influential cases that can lead to the improvement in the physiological state of trees in favor of reducing the fruit cracking. 
Materials and methods
In this study, the effects of silicon and potassium sulfate spraying were investigated on the fruit cracking and some quantitative and qualitative characteristics of pomegranate fruit. An experiment was conducted to evaluate the combined effects of four levels of silica (0, 100, 300, and 500 ppm) and three levels of potassium sulfate (0, 0.75%, and 1.5%) spraying on the fruit of pomegranate cv. ‘Malase-Saveh’, one of the most important pomegranate varieties of Iran. The treatments were applied three times during the growing season. The experiment was arranged in a factorial experiment based on the completely randomized block design in three replicates. Data analysis was performed using SAS statistical software and the means were compared using Duncan Multiple Range Test (DMRT) at 5% level of significance.
 Results and Discussion
The results indicated that most of the qualitative and quantitative traits were influenced by foliar spraying of these substances. Also, the results indicated that foliar application of silica, potassium sulfate, and their interaction significantly affected the fruit cracking. According to the results, the lowest fruit cracking (2.64%) was obtained by spraying 500 ppm silica and 0.75% potassium sulfate, while the highest fruit cracking (27.87%) was recorded from control plants. The highest fruit weight (204 g) was recorded in the treatment of 1.5% potassium sulfate and the lowest fruit weight (144 g) was recorded from untreated plants. Most of the treatments had a positive effect on fruit and aril weight and increased this character compared to the control. Spraying with 500 ppm silica and 1.5% potassium sulfate resulted in the highest (39.69 g) 100 arils weight, while control plants had the lowest (29.14) 100 arils weight. Silica and potassium sulfate treatment also improve the total soluble solid and titratable acidity in the fruit juice of pomegranate.
 Conclusion
The data obtained from this study could provide valuable insights into the effects of proper fertilization in reducing one of the main pomegranate disorders. Overall, the results indicated that combined spraying of silica (500 ppm) with potassium sulfate (1.5%) is more effective than their individual use and results in the higher fruit yield and quality, as well as a lower cracking disorder. These findings suggest that there are synergistic effects between these compounds. According to the results of this investigation simultaneous application of silica and potassium is suggested as a practical strategy in orchard management practices that could be beneficial for improving qualitative and quantitative attributes of pomegranate fruit.

Keywords

• Aril
• Fruit cracking
• Fruit quality
• Nutrition
• Potassium

Main Subjects

• H: Tropical and Subtropical Fruits