Creation For New-typed Brassica Napus And Studies On The Intersubgenomic Heterosis In Rapeseed

In the present paper, three parts were reported. 1: The genetic diversity of 21 different oilseed rapes was accessed according to the fingerprinting of AFLP and SSR markers. 2: The creation and cytogenetic analysis of the pentaploid hybrids (ArAnBcCcCn). 3: The study and the utilization of new-typed B. napus (ArArCcCc) on intersubgenomic heterosis. The main results were as follows:1 The primer selection was performed on 64 AFLP primer pairs and 27 were amplified well. In all, 1578 bands were amplified from 19 primer pairs with 83.05 bands on an average. 212 bands were amplified from 19 SSR primer pairs with 194 polymorphic bands.2 The cluster map obtained from 1, 2, 3 as far as 19 primer pairs were comparatived with the clustre map obtained from all data from 19 AFLP and 19 SSR, the results showed that 10 SSR and 3 AFLP primer could contruct a reliable cluster map. Correlation detected by 2-way Mantel test showed that the matrix correlation between the 1578 products from 19 AFLP, 212 products from 19 SSR and all data (19 AFLP+19 SSR) were 0.99911 and 0.99762 respectively. The correction between the dendrograms from UPGMA cluster analysis of 19 AFLP and 19 SSR primer combinations were also tested and the matrix correlation was 0.99388. From what have said we deduced that AFLP and SSR were all good molecular markers for assessing the genetic diversity of Brassica species.3 The hybrids were obtained through crosses between B. carinata (BcBcCcCc) and B. rapa (ArAr). Two methods were used for chromosome doubling of the trigenomic hybrids (ArBcCc), and hexaploid (ArArBcBcCcCc) were obtained. When chromosomes in somatic cells of trigenomic diploids was hybridized in situ with the genomic DNA of B. nigra, 16 chromosomes with strong signals could be sharply distinguished from other 38 chromosomes suggesting a close relationship and high homology between the two B genomes, one in B. nigra and the other in B. carinata, respectively. The hexaploid had intermediate phenotype between B. carinata and B. rapa and exhibited strong biomass heterosis compared to undoubted hybrids.4 To generate of pentaploid hybrids (ArAnBcCcCn), hexaploidy plants (ArArBcBcCcCc)with 27 bivalents in PMCs, were used as female parents to pollinate with pollen of four cultivars of B. napus (AnAnCnCn). Plants had been identified to be pentaploid with 46 chromosomes after chromosome numbers being carefully checked with prometaphase and metaphase cells from style tissue and anther wall. Strong signals shown that DNA probe of B. nigra hybridized well with the chromosomes of Bc genome in B. carinata and had the low homology with ArAn/CcCn genome whatever it came from B. carinatalB. rapa or B. napus.5 Chromosome pairing configurations in PMCs of pentaploid could be grouped into 12 classes with the following formula: 2-10 univalents + 16-22 bivalents + 0-3 trivalents + 0-1 quadrivalents. Nineteen or more than 19 bivalents could be observed in about 80% of PMCs, which implicated that 10 chromosomes of An genome and 9 chromosomes of Cn genome from B. napus in the pentaploid could pair each other well with their 10 compatriots of Ar genome from B. rapa and 9 compatriots of Cc genome from B. carinata respectively. Chromosomes orientated outside of equatorial plate and laggards were observed in the meiosis of pentaploid hybrids, GISH results revealed that those chromosomes were belonging to Bc genome.6 The subgenomic of all 38-chromosomed plants were estimated with constitution AFLP and SSR markers. About half genomic composition was replaced by Ar and Cc subgenomes in average in the new-typed B. napus. However, the ratio of substitution varied a lot with individuals, 24.04% and 27.48% of the special bands from B. rapa and B, carinata (Cc) on average and ISG (Ar+Cc) ranged from 11.61% to 83.25% with an average of 48.45%. It seems that the substitution happened in C genome was higher than that of A genome except the combination 1SH. The Bc genome specific bands were appeared in every plant of new-typed B. napus with low freq...