四季柚一年四季均能开花结果 ,但其经济产量主要由一次果和二次果构成。四季柚二次果结果母枝为当年春梢 ,盛花期 6月中旬 ,果实成熟期为次年2～ 3月。为开发利用四季柚二次果晚熟特性 ,遂于1996～ 1999年进行了本观察。1　材料与方法　　以苍南县马站镇中魁村、桥新村和马站供 Four grapefruit can blossom all year round, but its economic output is mainly composed of primary and secondary fruit. Four fruit grapefruit secondary fruiting branches when the spring shoots, full flowering in mid-June, the fruit maturity for the second year from February to March. In order to develop and utilize the secondary fruit of Siji grapefruit late-maturing characteristics, then in 1996 to 1999 for the observation. 1 Materials and Methods Cangnan County horse standing in the village, bridge village and horse station for