Document Type : Full Paper
Former Graduate Student, Faculty of Agriculture, University of Guilan, Iran
Assistant Professor, Faculty of Agriculture, University of Guilan, Iran
Professor, Faculty of Agriculture, University of Guilan, Iran
Leaf analysis is a general method of estimating the fertilizer needs in fruit trees, but there exists a limited correlation between it and fruit quality. Throughout the present study, fruits were harvested 10 weeks following full bloom and at the commercial maturity (6.2 brix) stages from thirteen different commercial kiwifruit orchards that had been fertilized with different fertilizers, the experiment being carried out in the east of Guilan province. Following harvest, such mineral elements as nitrogen, potassium, phosphorus, calcium and magnesium, dry matter and as well fruit tissue firmness(just in second harvest) were assessed. For an evaluation of the storage life, mature fruits were transferred to cold storage of 0 ºC temperature and 90-95% relative humidity, with fruit tissue firmness being evaluated after 105 days past of storage. Results showed significant correlations between fruit tissue firmness (at harvest) and potassium content in fruitlets and between fruit firmness and calcium, nitrogen, as well as dry matter content in mature fruits. There was a significant correlation observed between fruit firmness at the end of storage time and potassium as well as nitrogen content in fruitlets, and also between calcium, nitrogen contents and dry matter in mature fruits. Fruits with higher firmness at harvest time had maintained a higher firmness at the end of their storage period. Also, according to cluster analysis, the kiwifruit orchards were divided into two main groups. It could finally be concluded that the postharvest behavior of kiwifruits can be evaluated through a determination of the mineral compositions of fruitlets and of the mature fruits.