Abstract: 11e leaf color mutant found in the gynoecious line 9110G carl be inherited stably and diferent from the other mutants reported before，I11e cotyledon．first and second true leaf is golden at first． The chlorophyll content is about 60％ of the normal line．With the growth ofthe mutant．the color of the leaf turn into green slowly and was same to the normal plants．By observing the phenotype of F1、F2、BC，testing the content of chlorophyll and analyzing genetic regulation．we carl concluded that the mutant is nucleolus inheritance and is controlled by one pair of recessive gene．and green color is incomplete donrfinance to yellow color． e yellow color is due to the decreasing ofthe chlorophyl1． le mutant is a gooa material to research on photosynthetic system and gene position。And the mutant is also a useful marker to identify purity of F1 hybrids．

Key words: Cucumber, Leaf color mutant, Chlorophyll, Genetic