Selection And Identification Of Chinese Cabbage-cabbage Alien Addition Lines

Chinese cabbage (Brassica L.ssp. Compestris pekinensis) is one of the most important vegetable crops in China. In recent years, the unicity of breeding materials has become the bottleneck in Chinese cabbage breeding breakthrough. In order to breed the stable disomic alien addition lines, four disomic alien addition lines of Chinese cabbage-cabbage were identified from selfing F1 generations of Chinese cabbage-cabbage monosomic and double monosomic alien addition lines through traditional pressure film, karyotype and SSR analysis. Furthermore, the morphology, cytology and reproductive characteristics of the disomic alien addition lines were studied. It will provide the practical and theoretical basis for creating alien substitution lines and translocation lines of Chinese cabbage-cabbage, and will lay a foundation for studying interactions, mapping and expression of genes and accelerating genetic improvement in Chinese cabbage. The main research results are as follows:1. The plants with 2n=22 were identified from the Chinese cabbage-cabbage double monosomic alien addition lines 1# and 6# and the monosomic alien addition lines 3# ,7# and 9# by accounting the chromosome number in mitosis metaphase, with a proportion of 7.89%, 6.06%, 4.65% and 5.26% respectively. Using karyotypic analysis, four Chinese cabbage-cabbage double monosomic alien addition lines were identified to be introduced the cabbage chromosome 1#, 3#, 7# and 9#, named AC₁d, AC₃d, AC₇d and AC9d respectively.2. The meiosis behavior of Mother Pollen Cell (PMC) in three Chinese cabbage-cabbage double monosomic alien addition lines AC₁d, AC₃d and AC₇d were observed. The results indicated that the chromosome configuration forms at diakinesis in AC₁d, AC₃d and AC₇d were mainly 11II, with a ratio of 90.10%, 60.8%, 71.1% respectively. At metaphaseâ… , chromosomes were arranged in equatorial plate in most of cells, with a few exceptions of two chromosomes distributed out of equatorial plate. At Metaphaseâ… , many chromosome separations were existed, with the form 11-11 mainly. At Metaphaseâ…¡, chromosomes were mainly distributed with 11-11-11-11, with a ratio of 83.50%, 69.9% and 77.6% respectively.3. The pollen amounts, pollen uniformity and pollen viability of plant AC₁d, AC₃d and AC₇d were counted and compared with that of the diploid Chinese cabbage. The results showed that the characters of pollen characteristics in alien addition lines was significantly different from that in diploid Chinese cabbage, however there were no large differences among alien addition lines. The pollen uniformity of diploid Chinese cabbage was not significantly different from the double monosomic alien addition lines 3#, but was significantly different from other alien addition lines.4. The phenotypic analysis indicated that there were no significant differences in field traits such as growth vigor and plant shape between AC₁d and diploid Chinese cabbage in vegetative growth period. The plants of AC₁d, AC₃d,and AC₇d had partial cabbage characteristics such as late bolting, large petal and white flower in reproductive growth period, with different morphological traits and low seeding set.5. SSR primers anchoring linkage groups 03, 02,08 and 06 in cabbage were applied to identify allotriploid hybrids, Chinese cabbage, cabbage, monosomic and disomic alien addition lines. The amplified pattern of Chinese cabbage-cabbage disomic alien addition lines and Chinese cabbage-cabbage monosomic alien addition lines were similar to that of cabbage and allotriploid, but without corresponding bands in Chinese-cabbage. It showed that the introduced chromosome of Chinese cabbage-cabbage disomic alien addition lines AC₁d, AC₃d, AC₇d and AC9d were corresponded with linkage group 03, 02, 08 and 06 in cabbage.