و بهبود كيفيت ميوه هاي سيب در شهرستان نقده )K/CA( برهمكنش پتاسيم و كلسيم بر تغييرات نسبت پتاسيم به كلسيم

The Interactive Effects of Potassium and Calcium on the K/Ca and Quality of Apple Fruits (In Naghadeh)

Potassium and calcium are two important nutrients determining fruit quality. In order to study of KICa 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 = T,+ micronutrients, T3= T2+MOP (based on soil test), T4 = T3+ 4 times 0.5% CaC12 spray, T5= T3+ 8 times 0.5%CaC12 spray, T6= T2+MOP (50% above soil test), T7 -T6+ 4 times 0.5%CaCl2 spray, T8 =T6+ 8 times 0.5%CaCI2 spray, T9=T2+ K2SO4 (50% above soil test)+8 times 0.5% CaC12 spray. The results showed that foliar applications of CaC12 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 CaC12 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 CaC12 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 CaC12 (beginning 3 to 4 weeks after full bloom) is recommended.