Molecular And Cytogenetic Characterizations On Intertribal Hybrids Between Brassica Napus L. And Isatis Indigotica Fort.

Genetic resources of medicinal plants which have been researched and used for long are very rich in China. Medicinal plants contain medicinal components and other agricultural characters, for example the resistance to plant diseases and insect pests, stress tolerance and so on. It has been reported that genetic resources of medicinal plants were transferred into crops such as rice, carrot, grape and oilseed rape by the methods of sexual cross, somatic hybridization and gene engineering, to aim at (1) improving agricultural characters of crop resistance (2) improving quality by transferring medicinal components into crop (3) producing medicinal components of rare plants in crops. Therefore, in this investigation ,the intertribal hybrids between Brassica napus L.(2n=38) and Isatis indigotica Fort. (2n=14) were obtained through sexual cross in order to improve the quality of oilseed rape and analyzed by the methods of genomic in situ hybridization(GISH) and amplified fragment length polymorphism(AFLP). The results were described as follows.Among five F1 hybrid plants between B. napus and I. indigotica, four plants with fewer leaf splits, small flowers and low fertility were mixoploids and one plant was haploid with short plant, small leaves, small flowers and low fertility. In mixoploid plants, somatic cells with 2n=25²9 were most frequent except for a few haploid cells (2n=19) and chromosome doubling cells (2n=50⁶0). Abnormal chromosome behaviors were observed in pollen mother cells (PMCs) from mixoploid BI-1 and haploid, including chromosome bridges, laggard chromosomes, meiotic cycle asynchrony and unequal separation of chromosomes. Somaclonal variations analysis on mixoploid hybrid plant BI-1 showed that percentage of cells with 2n=25, 26 decreased and percentage of cells with 2n=29 ascended.Chromosome segments of I. indigotica were detected in mixoploid plant BI-1 by GISH analysis but their quantity was different in different cells. AFLP analysis showed that 8.79% bands were specific for I. indigotica, 12.38% novel for two parents and lots of deleted in B. napus in the mixoploid. In haploid, 6.99% bands specific for I. indigotica, 17.47% novel ones for two parents and lots of deleted ones in B. napus were also detected.In BCF₁ (F₁×B.napus), half of plants had only one specific chromosome numbers (2n=30～38), others were mixopliods. One plant with 2n=26, which had very few leaf split, small flowers, lanky petals and complete sterility , was obtained from BCF1 between F1...