Creation Of Several Cabbage-Chinese Cabbage Monosomic Alien Addition Lines

In order to creat the alien addition lines,the BC₁ plants derived from the backcross between the cabbage(Brassica oleracea vat.capitata L.)-Chinese cabbage(Brassica compestris L.ssp.pekinensis(Rupr)Olsson)allotriploid(ACC,2n=3x=28)and diploid cabbage are used as studying materials.The embryology,morphology and cytology of BC₁ plants are studied.Three monosomic addition lines and 2 dual monosomic addition lines are obtained from these BC₁ plants.The study provids basic materials for creating alien substitution and translocation lines of cabbage-Chinese cabbage,which would help to carry out the genetic improvement of cabbage,explore the relationship between A and C genomes,and study gene interaction,location and expression.The results are listed as follows:1.A backcross was made from the allotriploid as female parent and diploid cabbage as male parent.The observation on the fertilization and embryo development in the backcross was performed by the technologies of fluorescence microscopy and paraffin slice.The results showed that:(1)Few pollen grains germinated,and most germinated pollen tubes were distorted.The large callose on the surface of stigma papilla prevented pollen tubes from penetrating into the stigma,only a few pollen tubes can reach the micropyle.(2)The globular embryo was started to degenerate and the free endosperm nucleus were disintegrated in 11～13 days alter pollination,and only residual podosperms were observed alter the unfertilized ovule was degenerated.(3)The rate of seed setting for backcross progenies was very low with only 0.011%.2.Three monosomic addition lines and 2 dual monosomic addition lines were obtained from 8 plants of BC₁ by the observation of root tip cell mitosis and karyotypic analysis.BC₁-â‘ and BC₁-⑨were monosomic addition line with 7 chromosome of Chinese cabbage and BC₁-â‘¢was also monosomic addition line with 8 chromosome of Chinese cabbage,BC₁-â‘£was dual monosomic addition line with 4 and 8 chromosomes of Chinese cabbage and BC₁-â‘¥was also dual monosomic addition line with 6 and 9 chromosomes of Chinese cabbage.3.The PMC meiosis behavior of alien addition lines showed that:Monosomic addition lines BC₁-â‘ and BC₁-â‘¢and daul monosomic addition line BC₁-â‘£were further validated.To BC₁-â‘ and BC₁-â‘¢plants,the chromosome configurations at diakinesis were mainly shown 9â…¡+â… and one univalent was out of equatorial plate at metaphaseâ… ,the form of chromosomes separation was 10-9 at anaphaseâ… and 10-9-10-9 at anaphaseâ…¡.To BC₁-â‘£plant,the chromosome configurations at diakinesis were mainly shown 9â…¡+2â… ,the random separation of two univalents led to complex forms of chromosome separation at anaphase.4.The morphologic investigate of alien addition lines and their parents indicated that: there was a great difference in leaf shape,flower bud and petal characteristic between alien addition lines and diploid cabbage,especially for BC₁-â‘¢,which was obviously different from diploid cabbage in leaf shape,head shape and petal characteristic. Furthermore,BC₁-â‘¢was obviously better than BC₁-â‘ ,BC₁-â‘£and diploid cabbage in black spot disease resistance.5.The observation of pollen characteristics of alien addition lines and their parents showed that:there were obviously differences between alien addition lines and diploid cabbage,as well as among different alien addition lines;the correlation between pollen regularity and pollen viability of alien addition lines and their parents was significantly positive.