Cytogenetic Analysis Of Hybrid Between B. Napus And B. Oleracea

Brassica napus (rapeseed AACC) derived from hybridization between B. rapa and B. oleracea. During the long evolution and domestication, the genomes of rapeseed have became much different from parental species. The interspecific hybridization between rapeseed and B. oleracea is an important strategy to transfer traits and to widen germplasm. In this study, cytogenetics of hybrids from B. napus and B. oleracea was analyzed in order to provide thesis basis to transfer genetic components each other.The results are as follows:1. Compatibility between B. napus and B. oleraceaAmong ten types of wild B. oleracea pollinated to B. napus, five types did not produce hybrid seeds with B. napus, while a few hybrid seeds could be obtained from four cultivar B. oleracea. Exactly, 442 seeds of F1 were obtained when 2,026 flowers of B. napus were pollinated with B. oleracea, resulting that the seed setting rate was 21.8%. No significant differences between wild and cultivar B, oleracea can be found for the compatibility with B. napus.2. Identification of hybrid between B. napus and B. oleraceaThree plants, coden as 197,199 and 201 were identified to be true hybrids by the observation from phenotype, cytology, pollen fertility and SSR marker.3. Cytogenetic analysis of F1 between B. napus and B. oleracea(1) PMCs of F1 were checked at diakinesis with main results shown below:In hybrid 197, the chromosome behavior was (0-1)Ⅴ+(0-1)Ⅳ+(0-1)Ⅲ+(7-11)Ⅱ+(6-10)Ⅰ, and the most common configuration was 9Ⅱ11+10Ⅰ(60.17%). The chromosomes pairing in hybrid 197 was 9.06Ⅰ+9.12Ⅱ+0.10Ⅲ+0.08Ⅳ+0.01Ⅴ. In hybrid 199, the chromosome behavior was (0-1)Ⅳ+(0-1)Ⅲ+(8-10)Ⅱ+(6-10)Ⅰ, while chromosomes pairing in 84.71% PMCs was 9Ⅱ×10Ⅰ. The chromosomes pairing in hybrid 199 was 9.66Ⅰ+9.12Ⅱ+0.01Ⅲ+0.02Ⅳ. However in hybrid 201, the chromosome behivor was (0-2)Ⅳ+(0-4)Ⅲ+(5-14)11+(0-10)Ⅰ. And the most pattern of configuration was 10Ⅱ+8Ⅰ(33.51%) and 9Ⅱ+10Ⅰ(27.32%). The chromosomes pairing in hybrid '201'was 7.48Ⅰ+9.81Ⅱ+0.13Ⅲ+0.07Ⅳ. (2) The chromosomes segregation in hybrid 197 was 13:15 (45.9%),12:16 (22.4%),14:14 (13.39%). For hybrid 199 it was 13:15 (36.81%),12:16 (30.77%),14:14 (15.93%), while it was 13:15 (42.65%),12:16 (21.08%) and 14:14 (23.53%) in hybrid'201'. Highest fitness between theory and observation in all of 3 hybrids is 9:19.(3) In some cases, the phenomena of lagging chromosome and chromosome bridge could be observed at anaphaseⅠand anaphaseⅡin pollen mother cells of F1 hybrid; in the telophase, chromosomes were divided into three or more groups.4. Microspore culture of F1 between B. napus and B. oleraceaOne hundred fifty embryos were gained in hybrid 199 but only 44 individuals can survive in the field. Among 42 plants checked chromosomes, wide variants of chromosome number could be found. For example,9 plants were mixploids, and other 33 plants chromosomes number varied from 15 to 66. Our data suggested that the observation value of the frequency of euploid was higher (7.14%) than thereotical value.Taken together, the major of chromosome behavior in Fl between B. napus and B. oleracea was the pattern of 9Ⅱ+10Ⅰand 10Ⅱ+8Ⅰ, and high frenency of euploid could be found in the progenies of F1 between B. napus and B. oleracea.