No abstract

Paternal inheritance of mitochondrial DNA (mtDNA) of Cucumis hystrix Chakr. was revealed in the interspecific crosses of cucumber (C. sativus L.) x C. hystrix. The mtDNA was analyzed by RFLP analysis of a PCR amplified nad4 exon1 and nad4 exon2 region of the female parent C. sativus, male parent C. hystrix and the hybrids. All the hybrids showed the identical restriction pattern of C. hystrix. This indicated the paternal inheritance of mtDNA. A similar experiment with chloroplast DNA (cpDNA) was performed by RFLP analysis of a PCR amplified rbcL-ORF106 region. The results showed the identical restriction pattern of the female parent C. sativus in the same hybrids. This indicated the maternal inheritance of cpDNA. Paternal transmission of the mitochondrial genome of C. hystrix was newly discovered in the Cucumis hybrids.

To produce doubled haploid homozygous male-sterile line of eggplant with the cytoplasm of Solanum grandifolium, anther culture of the male-fertile (MF) BC 5 in the S. grandifolium induced CMS system was done. Anthers were cultured in an embryo induction medium and were heated to 35℃ for 3 d in the dark and then transferred to 25℃ under a 16 h photoperiod. After 20 d the anthers were transferred to a germination medium. The presence of pollen in the anther, number of chromosomes in the root tip cells, size of the stomatal guard cells and pollen fertility of the regenerated plants were investigated. The frequency of embryo formation in the MF line was 1.02%. From the embryos, one regenerated plant showed pollen non-formation type male sterility. Root tip chromosome number and stomatal guard cell size confirmed that the regenerated male-sterile plant is a microspore originated doubled haploid through spontaneous chromosome doubling. The present study demonstrates the first successful production of a doubled haploid homozygous male-sterile line in a CMS system of eggplant with the cytoplasm of S. grandifolium. Therefore, this material could be a useful breeding material for eggplant and improve the speed of conventional breeding.