Study on leaf mineral nutrient and its effect on fruit quality of Gonggan (Citrus reticulata Blanco var. gonggan).

Gonggan was a superexcellent local variety of Citrus reticulata Blanco in Guangdong province,south China.An analysis of mineral contents in leaves of Gonggan from different orchards was carried out for determining the status of leaf mineral nutrition and its relationship with the traits for fruit quality.The results indicated that the contents of various mineral elements in the leaves collected from different orchards exhibit significant difference with the coefficients of variation between 0.20-0.49,in which the contents of Mn,P,Mg,and Zn show a greater variation.The integrated evaluation with the 'synthetic reasonableness and satisfaction index (SRSI)' suggested that the soluble solid matter content(SSMC),juice ratio(JR),acid content (AC),seed number(SB),fruit shape index(FSI) and special flavor(SF) would be the most important traits for improving quality of Gonggan fruits.Significant correlations(P0.05) were observed between the N content of leaf and soluble solid content(0.642*),Mg and special flavor (0.607*),Mg and juice ratio(0.719**),as well as Mn and fruit shape index(-0.673*).The results indicated that the nutrition of elements N,Mg,Mn in leaves affected significantly the fruit quality of Gonggan in the different orchards.