The Studies Of Tobacco Germplasm By Distant Hybridization Between Tobacco And Medicinal Plants

Based our previous studies, this current investigation is to breed novel tobacco germplam with medicinal value by distant hybridization between tobacco (Nicotiana tabacum L.) and medicinal plants such as Coimum bailicm L. and Petilia frutoscenal Britt . we developed an optimal strategy for tobacco distant hybridization and three new hybid lines of tobacco with medicinal value, which were approved by a series of analysis such as offspring variants and their genetics , chloroplast content . The optimal technology for tobacco distant hybidization included using the grafted tobacco plants as female, repeated pollination by pollen from medicinal plants and establishing an environmental condition with lower temperature and higher moisture for crossing. Combined use of these techniques could effectively overcome hybridization incompatibility. The hybrid progenies were backcrossed with tobacco as a recurrent parent, which could greatly improve the hybrid sterility. The hybrid generated a lot of different variants. which exhibited a higher similarity with tobacco plants in the main agronomic traits while they also showed the characteristics of medicinal plants in the traits such as leaf color and shape, axillary bud growth and resistance. Chemical analysis of the leaf , chloroplast content analysis and photosynthesis analysis displayed that the genetically hybrid contained the medicinal components which exit in the medicinal plants used as male parents, but not in the tobacco plants used as female parents. Compared with the commercial tobacco varieties, these new hybrid have a middle or less nicotine and lower level of total sugar in their leaves. In addition, different hybrid lines have different improvement in chloroplast content, accompanyed with photosynthesis. Chromosome analysis indicatted that chromosome disappear heterozygous state, that is to say, the euploid and aneuploid exit the same cell in these genetically hybid bred by distant hybridization between tobacco and medicinal plants. The data of esterase isoenzyme, CAT analysis, stoma density analysis and glandular hair density analysis indicated that these hybid integrated some loci derived from the medicinal plant genomes and had a new characteristic of gene expression. In conclusion, these genetically hybrid bred by distant hybridization between tobacco and medicinal plants have some new different transpiration and special aroma. Assessment analysis and concotion analysis revealed that in these genetically hybid bred by distant hybridization between tobacco and medicinal plants had special aroma. Leaf color by concotion was declined to fale characteristics and different hybrid had different raise in production. They are new types of tobacco germplasm with potential in tobacco breeding and industry.