Mapping Quantitative Trait Loci Influencing Cucumber Carpopodium Length Using Simple Sequence Repeat Markers Mapping Quantitative Trait Loci Influencing Cucumber Carpopodium Length Using Simple Sequence Repeat Markers Roles of Sucrose-metabolizing Enzymes in Sugar Accumulation in Leaves and Carpopodiums of Ziziphus jujuba Mill.cv.Lingwuchangzao