Survey on nutritional status and fruit quality of Citron (Citrus medica L.) in southern Italy

Citron (Citrus medica L.) cultivation in the Mediterranean basin occurs in Corsica, Crete and southern Italy, especially in Calabria region. Citron’s cultivation in Calabria is extended on a small area with a relevant local economic importance. From commercial and industrial point of view the most important cultivar is “Liscio di Diamante”. Citron production is totally used for industrial transformation (candied, jams, liquors, syrups and drinks), while oils are utilized in pharmaceutics and cosmetics. Aim of the research was the characterization of citron nutritional status, fruit quality and essential oils in two districts of the cultivated area with different soil and climate characteristics and to evaluate the relationships between nutrients in leaves and qualitative parameters in fruits. Two homogenous districts were identified: (A) Santa Maria del Cedro located at sea level; (B) Buonvicino located at 300 meters on sea level. Forty representative farms were chosen within the districts and studied for three years. For each farm, several sampling campaigns were realised to determine soil physical-chemical characteristics, plant nutritional status and fruit characteristics. Moreover, sixty-eight buffing citron essential oils were analyzed by GC/MS. The most part of soil parameters of two districts were significantly different, in particular in B available phosphorous and exchangeable potassium values were significantly higher than A, characterized by higher values of total lime and pH. Leaf nitrogen values in both districts were higher than the optimal range standard in orange. Plants nutritional status showed relevant differences between the two sub-zones. Zinc, manganese and calcium showed significantly higher values in A. All essential oils were characterized by the presence of limonene, -terpinene and -myrcene as main constituents. -Pinene, -pinene, -thujene, sabinene, -fellandrene, -terpinene, neral, geranial, neril acetate, geranil acetate, -cariofillene e -bisabolene were also identified. Several differences were observed in the comparison of hill and plain samples. Calcium content in leaves was highly correlated with fruit weight. Micronutrient leaf levels influenced some physical fruits parameters.