Study On Distant Cross Generations F1 And F2 By Distant Hybridization Between Tobacco And Medicinal Plants

This current investigation is to breed tobacco germplam with medicinal value by distant hybridization between (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 two new hybrid lines of tobacco with medicinal value .which were approved by a series of analysis such as offspring variants and their genetics,choroplast content.The optimal technology for tobacco distant hybridization 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 colour and shape,axillary bud growth and resistance.Choroplast content analysis and photosynthesis analysis, transferring 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.In addition, differdnt hybrid lines have different improvement in chloroplast content,accompanied with photosynthesis,and yield has increased in the hybrid progenies.Chromosome analysis indicated that chromosome disappear heterozygous state,that is to say,the euploid and aneuploid exit in the same cell in these genetically hybrid bred by distant hybridization between tobacco and medicinal plants.The morophology has displayed differences in the offsprings with their parents.The data of esterase isoenzyme analysis indicated these hybrid integrated some loci derived from the medicinal plant genomes and had a new characteristic of gene expression.In a word, the hybridization results is successful and they are new types of tobacco germplasm with potential in tobacco and industry.