SUCCESSFUL INTERSPECIFIC HYBRIDIZATION BETWEEN CUCUMIS-SATIVUS L. ANDC. C-HYSTRIX CHAKR

Interspecific F-1 hybrids were obtained from a cross between Cucumis s ativus L. (2n = 2x = 14) and C. hystrix Chakr. (2n = 2x = 24). Control led crossing resulted in fruit containing embryos which were excised a nd rescued on a Murashige and Skoog solid medium. A total of 59 vigoro us plants were obtained from a fruit containing 159 embryos (37.3% reg eneration rate). Hybrid plants were morphologically uniform. The multi ple branching habit, densely brown hairs (especially on corolla and pi stil), orange-yellow coIlora, and ovate fruit of F-1 hybrid plants wer e similar to that of the C. hystrix paternal parent. While appearance of the first pistillate flower was more similar to that of C. sativus maternal parent than to C. hystrix, staminate flower appearance was mi d-parent in occurence. The diameter and internode length of stem, shap e and size of leaves and flowers were intermediate when compared to th e parents. An elongated green, trilobate style/stigma which was not ap parent in either parent was observed in staminate flowers of F-1 plant s. Similarly, the style/stigma of pistillate flower of F-1 plants were longger when compared to their parents. The brown pubescence observed on pistillate flowers of the F-1 and C. hystrix was not observed on t he C. sativus parent. The somatic chromosome number of F-1 plants was 19. Two morphologically distinct groups of chromosomes were observed i n the F-1 hybrid; 7 relatively large chromosomes characteristic of C. sativus, and 12 smaller chromosomes characteristic of C. hystrix. Anal ysis of malate dehydrogenase isozyme banding patterns provided additio nal confirmation of hybridity. Reciprocal crossing of F-1 plants to ei ther parent and self-crossing indicated that the hybrids were male and female sterile.