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Xiao L.,Qinghai Academy of Agricultrual and Forestry science | Zhao H.,Qinghai Academy of Agricultrual and Forestry science | Zhao Z.,Qinghai Academy of Agricultrual and Forestry science | Du D.,Qinghai Academy of Agricultrual and Forestry science | And 4 more authors.
Molecular Breeding | Year: 2013

Most of the germplasm resources in Brassica juncea produce silique with only two locules, whereas a few varieties can produce silique with three or four locules. The increase in locule number in B. juncea has been shown to cause an increase in the number of seeds per silique, resulting in an increase in the yield per plant. Thus, the development of high-locule-number varieties may be an effective way of improving the yield of B. juncea. Duoshi, a B. juncea landrace originating from the Qinghai-Tibetan plateau, produces silique with 3-4 locules. Genetic analysis has shown that the high-locule-number trait in Duoshi is determined by two recessive genes, tentatively designated as Bjln1 and Bjln2. For fine mapping of the Bjln1 gene, a BC3 population was developed from the cross between Duoshi (multilocular parent) and Xinjie (bilocular parent). Using a combination of amplified fragment length polymorphism (AFLP) and bulked segregant analysis, only two AFLP markers linked to Bjln1 were identified. Preliminary linkage analysis showed that the two AFLP markers were located on the same side of Bjln1. Blast analysis revealed that the sequences of the two AFLP markers had homologues on Scaffold000019 at the bottom of B. rapa A7. Using the results of linkage analysis and BlastN searches, simple sequence repeat (SSR) markers were subsequently developed based on the sequence information from B. rapa A7. Seven SSR markers were eventually identified, of which ln 8 was co-segregated with Bjln1. ln 7 and ln 9, the closest flanking markers, were mapped at 2.0 and 0.4 cM distant from the Bjln1 gene, respectively. The SSR markers were cloned, sequenced and mapped on A7 of B. rapa (corresponding to J7 in the A genome of B. juncea). The two closest flanking markers, ln 7 and ln 9, were mapped within a 208-kb genomic region on B. rapa A7, in which the Bjln1 gene might be included. The present study may facilitate cloning of the Bjln1 gene as well as the selection process for developing multilocular varieties in B. juncea by marker-assisted selection and genetic engineering. © 2013 Springer Science+Business Media Dordrecht.

Xu J.F.,Zhejiang University | Long Y.,Huazhong Agricultural University | Wu J.G.,Zhejiang iversity | Xu H.M.,Zhejiang University | And 4 more authors.
Euphytica | Year: 2015

Glucosinolate and erucic acid are important plant compounds in rapeseed believed to have numerous functions in rapeseed-environment interactions. However, little is known about the QTL information related to the two different genetic systems including the embryo nuclear chromosomes and maternal plant nuclear chromosomes for glucosinolate content (GSLC) and erucic acid content (EAC) in rapeseed. Differences in QTL distribution between these two genetic systems, which control the performance of GSLC and EAC across different environmental conditions, were analyzed in the present study. A set of 202 DH populations derived from an elite hybrid cross of ‘Tapidor’ × ‘Ningyou7’ and their two backcross populations BC1F1 1 (DHs × Tapidor) and BC1F1 2 (DHs × Ningyou7) generated in two years were used as experimental materials for the study. A total of nine loci for GSLC and three loci for EAC with significant embryo additive main effects, embryo dominant main effects and/or maternal additive main effects, explaining 83.8 and 89.7 %, respectively, of their phenotypic variation, were identified. Although QTL × environment interaction effects were also detected in the present experiment, they played a minimum role in influencing the phenotypic variation. It was noted that qEAC-7-1 for EAC mapped on linkage group A7 was detected as the major QTL and could explain 68.32 % of the phenotypic variation for this trait. These results could be useful for the molecular maker-assisted breeding of GSLC and EAC quality traits based on the influence of two genetic systems. © 2015, Springer Science+Business Media Dordrecht.

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