Document Type : scientific research article
Authors
1
Ph. D. student in Soil Science, Department in Soil Sciences and Engineering,
2
Department of Soil Sciences and Engineering, College of Agronomy, Sari Agricultural Sciences and Natural Resources.
3
Citrus and Subtropical Fruit Research Center, Horticultural Science Research Institute, Agricultural Research and Education Organization (AREO), Ramsar
4
Dept. of Soil Science and Engineering, Sari Agricultural Sciences and Natural Resources University;
5
Horticultural Science Research Institute, Citrus and Subtropical Fruit Research Center, Agricultural Research and Education Organization (AREO), Ramsar
10.22069/jopp.2025.22948.3203
Abstract
Background and purpose: Calcium is the most required substance in fruit and it can be considered as the most important mineral element that is involved in determining the quality of fruit. One of the ways to improve the quality and firmness of the fruit texture is to feed the leaves of kiwi fruit vines during the fruit growth period. Therefore, this research was conducted in order to investigate the effect of the type of calcium fertilizer source on the quantitative and qualitative characteristics of "Hayward" kiwi fruit at the time of harvest.
Materials and Methods:
materials and methods: Experiment in the form of complete randomized blocks with three sources of calcium supply including calcium chloride, calcium nitrate and calcium silicate and 3 replications and two foliar spraying times. The first time: the beginning of foliar spraying in the fast growth phase of the fruit and in the second time, the beginning of foliar spraying in the slow growth phase of the fruit It was done on kiwi fruit vines. Two weeks after the end of foliar spraying, leaf sampling was done and nitrogen, calcium elements were measured in the leaf. After the amount of soluble solids reached 6.2%, the fruits were harvested and qualitative and quantitative characteristics including fruit weight, fruit skin color, soluble solids (TSS), fruit dry matter percentage, fruit texture firmness, titratable acidity , the amount of vitamin C, total fruit phenol, fruit nitrogen, fruit potassium, fruit calcium and fruit phosphorus were measured.
Results:
The results show the positive effect of foliar spraying of calcium treatments on the increase of calcium and nitrogen in leaves and fruits. Calcium nitrate and calcium chloride treatments led to a 21% increase in fruit weight in the first phase of fruit growth. Foliar spraying has increased the hardness of fruit tissue in calcium chloride and calcium nitrate treatments in the first and second phases of foliar spraying compared to the control treatment. The highest percentage of fruit dry matter was in calcium chloride treatment. Calcium nitrate treatment has increased the titratable acidity of the fruit by 11% compared to the control. The foliar spraying treatments in the first and second phases of foliar spraying had no effect on the amount of dissolved solids. Vitamin C was the highest in the first phase of foliar spraying in calcium chloride treatment and in the first and second phase of foliar spraying in calcium nitrate treatment. Also, foliar spraying increased the amount of phenol in the treatments compared to the control treatment.
Conclusion:
Based on the results of this research, it can be said that foliar spraying of calcium treatments during fast growth and slow fruit growth had a positive effect on the quality characteristics of the fruit, especially firmness. Foliar spraying of calcium chloride treatment had better results on fruit quality characteristics than other treatments. Due to the storage of kiwi fruit in the cold room and due to the importance of the shelf life of the fruit in the cold room, it is recommended to spray calcium chloride during the fruit growing season in the fast and slow growth stages of the fruit.
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