Obtaination And Studies Of A Few Chinese Cabbage-cabbage Monosomic And Disomic Addition Lines

In order to creating the alien addition lines, the BC₁ and BC₂ plants which come fromcrosses of Chinese cabbage-cabbage sesquidiploid individuals (ACC, 2n=3x=28) backto Chinese cabbage diploid were used as testing materials. Morphologic, cytology andreproductive characters of the BC₁ and BC₂ plants were studied and 2 monosomicaddition lines and 1 disomic addition line were obtained. This study provided theorybasic for creating alien substitution lines and translation lines of Chinese cabbage andcabbage, and helped to carry out Chinese cabbage genetic improvement, explore therelation between A and C genomes, study gene intactions, location and expression. Theresults were as followed:1. The field character of BC₁ and BC₂ plants showed multiplicity and there wassignificant difference among plants. Some characters of BC₁ plants, such as leaf shape,leaf color, leaf surface character, floral organs and so on, were similar to cabbage. Butmajority of BC₂ plants were similar to Chinese cabbage in growth vigour and externalmorphology. Individual plants in BC₁ or BC₂ groups were decrepit and dead quickly atthe reproductive growth time. The reason may be possible that gene normal expressionwas effected due to alien chromosome interruption.2.2 plants with 21 chromosomes were identified from 11 BC₁ plants, and 3 plants having21 chromosomes and 1 plant with 22 chromosomes were identified from 23 BC₂ plantsby taking account of the chromosome number of PMC meiosis anaphaseâ… and anaphaseâ…¡. Comparing with BC₁ group, the plants with 2n≤20 appeared in BC₂ group, the rate ofplants with 2n≥23 fell distinctly, but the rate of plants with 2n=21 or 22 didn't changeobviously. Generally speaking, the number of addition chromosome of BC₁ plants wasmore, whereas that of BC₂ plants decrease gradually.3. PMC meiosis behavior of BC₁ and BC₂ plants showed that: 1) To some plants with 20chromosomes, some phenomena such as chromosome lagging and losing, occurred in theprocess of chromosome paring and separating, which indicated that crossing over andtranslocation of chromosomes between Chinese cabbage and cabbage maybe occuramong these plants. 2) To the plants with 21 chromosomes, PMC meiosis may be classedtwo types. One type was that chromosome configurations at diakinesis were mainlyshowed 10â…¡+â… and the form of chromosome separation at anaphaseâ…¡was 10-10-11-11;Another one type was that chromosome configurations at diakinesis were mainly showed9â…¡+â…¢and variable number chromosomes moved to the poles early or lately during theprogress of chromosome separation. 3) To the plants with 22 chromosomes, chromosomeconfigurations at diakinesis were mainly showed 10â…¡+â… +â… . The random separation of 2 univaients led to complex forms of chromosome separation at anaphase. 4) To the plantswith 2n≥22, there were many formations of chromosome synapsis at diakinesis. Therate of multivalents was increased distinctly, which lead to more chromosomes lag orlose. The separation formation represented multiformity.4. The characters of pollen and leaves stoma, the podding set and seeding set by self werecounted. The results showed that there was significant difference between BC₁ and BC₂plants and Chinese cabbage diploid parent. Significant positive correlation was betweenpollen amount and pollen viability, podding set and seeding set.5. Two monosomic addition lines with cabbage chromosome No. 7(CO-7-1) and No. 9(CO-9-2) identified from BC₁, and one disomic addition line with cabbage chromosomeNo. 7 (CO-7-1D) identified from the CO-7-1 inbred progeny was obtained by karyotypeanalysis.