| Summary: | 碩士 === 國立臺灣大學 === 植物學研究所 === 83 === An allotriploid hybrid (genomes PPS) obtained from proto-plast fusion between haploid Nicotiana plumbaginifolia (P, n=10) and haploid N. sylvestris (S, n=12) was backcrossed to monosomic chromosome addition lines. A total of 93 2n=21 plants, each containing a 2n chromosome complement of N. plumbaginifolia and a single chromosome of N. sylvestris, appeared in the BC and BC ge- nerations. The 2n=21 plants could be classified into 13 groups based on morphological characteristics. The N. sylvestris chromosomes in the 2n=21 plants were determinated by RFLP markers and karyotype analysis. Of the 61 RFLP markers ana- lysed, 13 could not detect N. sylvestris DNA bands in the 2n= 21 plants, whereas the remaining 48 markers (including rRNA and NR genes)identified 9 normal and 4 aberrant lines. The N. sylvestris chromosomes in the normal lines were chromosomes 9(sat-1), 10 (sat-2), 11 (sat-3), 12, one of the A group, one of B group, and three of the C group, respectively. The N. sylvestris chromosomes in the aberrant lines could not be identified with certainty, but presumably they were translo- cated or deleted chromosomes. One morphologically distinct 2n=21 plant showed no chromosomal and DNA changes judged by karyotype and RFLP analysis. The rRNA genes in sat-3 chromo- some do not usually express in diploid N. sylvestris, but are active when added to the genetic background of diploid N. plumbaginifolia.
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