Document Type : Research Paper

Abstract

Potassium and calcium are two important nutrients determining fruit quality. In order to study of K/Ca ratio of fruits in firmness and storage shelf-life of fruits, an experiment carried out in RCBD on Golden delicious apple with 9 treatment in 5 replication in Naghadeh in 2001. The experimental treatments including: T₁= control, T₂ = T₁+ micronutrients, T₃= T₂+MOP (based on soil test), T₄ = T₃+ 4 times 0.5% CaCl₂ spray, T₅= T₃+ 8 times 0.5%CaCl₂ spray, T₆= T₂+MOP (50% above soil test), T₇ =T₆+ 4 times 0.5%CaCl₂ spray, T₈ =T₆+ 8 times 0.5%CaCl₂ spray, T₉=T₂+ K₂SO₄ (50% above soil test)+8 times 0.5% CaCl₂ spray.
The results showed that foliar applications of CaCl₂ solutions increased fruit firmness compared with fruits receiving high rates of potassium but no calcium. The greatest firmness was obtained with 8 times application of CaCl₂ solution. Treatment 6, which involved the application of potassium at 1.5 times the soil test but no foliar application of calcium chloride, resulted in the lowest firmness. There were no significant differences among the treatments with regard to pH, TA and TSS; However the fruit calcium contents were significantly different in treatments..
Fruits K/Ca ratio was 44 in control and increased about 58 in T₆. But in T₈ with optimal consumption of fertilizer and eight times CaCl₂ 0.5% spray, this ratio reduced to 20. The treatments did not   affected on fruit firmness in 90 days after storage significantly. Therefore, in order to increase the calcium of fruits and to improve the fruit firmness
8 biweekly foliar applications of CaCl₂ (beginning 3 to 4 weeks after full bloom) is recommended.

Keywords

• calcium chloride
• Fruit Firmness
• Golden Delicious
• potassium chloride
• Potassium/Calcium Ratia
• Potassium sulfate
• storage life

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