Abstract: The percentage of fruit set and seed set in the crosses between amphidiploid (Cucumis × hytivus Chen and Kirkbride, 2n = 38) , and south and north ecotype cucumber cultigens (C. sativus L. , 2n =14) , and genetic variation in these progenies were investigated. The percentage of fruit set in all crosses was high (83% - 100% ). The ratio of fruitwith embryo was 60% - 67% in the crosses between C. × hytivus and cucumber cultigens. Each fruit had about 10 - 20 embryos, which could survive and develop into plantlets through embryo rescue. The chromosome number of these plantlets was 26, as allotriploid. When cucumber cultigens crossed with amphidiploid C. ×hytivus, three fruits were obtained. One fruit had about 180 embryos 80% of which could survive through embryo rescue, and the chromosome numberwas 26. Others produced 60 seeds ( as HH1 population) and 15 ones with 14 hromosomes similar to that of cucumber cultigens, respectively. Few fruits with embryos or seeds were obtained in the crosses between allotriploid and cucumber cultigens. HH1 population was selected to investigate the genetic variation from morphology and molecular markers. Four plants showed the original parent C. hystrix traits such as black spines on fruit, while six plants had multiple branchng habits and unique morphological characteristics such as orange skin of fruit. Nineteen SSR primer pairs produced 63 alleles in HH1 and 24 alleles (38.1% ) were segregated, and seven of them might come from C. hystrix. From 400 arbitrary primers screened, twenty-four produced varied primed sites and among the 186 primed sites 31.7% were segregated. The results suggested that the genes of C. hystrix could be introduced into cucumber through interspecific hybridization and introgression.

Key words: Cucumber, C. ×hytivus, SSR, RAPD, Introgressive hybridization, Genetic variation