Dissertation > Agricultural Sciences > Crop > Economic crops > Oil crops > Rapeseed ( Brassica )

Identification of Cyto-and Molecular Genetics of Multisomic Addition Line "Nj08-063" in Brassica Napus and Its Agronomical Traits

Author QiYuJie
Tutor QiCunKou
School Nanjing Agricultural College
Course Crop Genetics and Breeding
Keywords Brassica napus Multisomic addition line Cytology PCR Genomic in situ hybridization/GISH Southern blotting
CLC S565.4
Type Master's thesis
Year 2011
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Distant hybridization is an important approach for crop genetic improvements. Brassica carinata is characterized by several desirable agronomic characteristics, such as yellow seed-coat color, reducing pod shattering and tolerant to drought stress. Therefore transfer these positive traits to B. napus by distant hybridization is becoming more and more important on rapeseed breeding. The progenies of "Nj08-063", which derived from an inter-specific cross of Brassica napus and B. carinata, were studied by cytological genetic observation, GISH and Southern blot, in order to learn about the structure and composition of the genome and the relationship with the agronomical traits. The new germplasm created in this study could be used in rapeseed breeding and some other researches. Main results are as follows:1. Morphology and agronomic traits in the progenies of "Nj08-063":Morphology variations in progenies of "Nj08-063" were observed,72.73% plants were shorter than their parents; some of them had low fertility and resulting no or little seeds. The seed-coat color of the progenies of "Nj08-063" were various, include yellow, brown and black, and the erucic acid content in this population were ranged from 0.47% to 40.16%.2. The results of cytological genetic observation:The chromosome number in the populations of "Nj08-063" and progenies ranged from 2n=34 to 44 and 2n=34 to 41, and the average numbers were 37.66±2.56 and 37.68±2.36, respectively. The base chromosome configuration were (0-4)Ⅰ+(16-23)Ⅱ+(0-2)Ⅲand (0-8)Ⅰ+(14-24)Ⅱ+(0-4)111+(0-1)IV at the meiotic metaphaseⅠ. Abnormal chromosome behaviors such as univalent (21.83%) chromosome bridges(1.45%), lagging chromosomes(4.84%), meiotic cycle asynchrony (0.39%). chromosome unequal distribution at meiosis stage were often observed in the populations of Nj08-063. The Studying on the number chromosomes in "Nj08-063" showed that "Nj08-063" had more than 38 chromosomes, and were confirmed as multisomic addition line.3. GISH and Southern blot analyses:The results of GISH show that no bright signals were covered with B. nigra probe on the chromosomes of the progenies of "Nj08-063" Southern blot showed that the signal appeared on B. carinata and B. nigra, and no signal appeared on the B. napus and the progenies of "Nj08-063". These results indicated that no B genome specific sequence which localized in the centromeric region of each B genome chromosome was detected in the progenies of "Nj08-063".The results of above showed that the progenies of "Nj08-063" with some traits, such as agronomic traits, yellow-seeded and the higher levels of erucic acids, from B. carinata "dodolla’. Study on GISH and molecule identification in progenies of "Nj08-063" shows that there may be not have the entire B-genome in the progenies of the "Nj08-063". The progenies of "Nj08-063" had more than 38 chromosomes, suggested that the extra chromosome beyond the normal B. napus derived from the duplication of the genome of A and/or C. Further studies are needed to be done to confirm the result.

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