Abstract: In this experiment, 12 self-line materials of two main cultivars in Cucurbita were crossed. There were 72 reciprocal cross combinations. The compatibility difference between reciprocal crosses and different materials, and the features of hybrid progenies were studied. The results showed that C. pepo L. was only suitable to be female parent and C. maxima D. was only suitable to be male parent in carrying out interspecific hybridization between C.pepo L. and C. maxima D. The variability of crossing compatibility was indicated by differences in percentages of setting, embryo fruit rate and embryo rate. The hybrid infertility were related to their cross compatibility. The possibility of improving C. pepo L. by crossing with C. maxima D. was also discussed in the paper．

Key words: Cucurbita maxima D., interspecific hybridization, compatibility