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Zhang K.,Southwest University | Zhang K.,Sweet Potato Engineering and Technology Research Center | Wu Z.-D.,Southwest University | Li Y.-H.,Southwest University | And 13 more authors.
Journal of Integrative Agriculture | Year: 2014

To determine the genetic diversity and population structure of sweet potato accessions cultivated in China, and to establish the genetic relationships among their germplasm types, a representative collection of 240 accessions was analyzed using inter-simple sequence repeat (ISSR) markers. The mean genetic similarity coefficient, Nei's gene diversity, and shared allele distance of tested sweet potato accessions were 0.7302, 0.3167 and 0.2698, respectively. The 240 accessions could be divided into six subgroups and five subpopulations based on neighbor-joining (NJ) clustering and STRUCTURE results, and obvious genetic relationships among the tested sweet potato accessions were identified. The marker-based NJ clustering and population structure showed no distinct assignment pattern corresponding to flesh color or geographical ecotype of the tested sweet potato germplasm. Analysis of molecular variance (AMOVA) revealed small but significant difference between white and orange-fleshed sweet potato accessions. Small but significant difference were also observed among sweet potato accessions from the Southern summer-autumn sweet potato region, the Yellow River Basin spring and summer sweet potato region and the Yangtze River Basin summer sweet potato region. This study demonstrates that genetic diversity in the tested sweet potato germplasm collection in China is lower than that in some reported sweet potato germplasm collections from other regions. Pedigree investigations suggest that more diverse Chinese sweet potato varieties should be formed by broadening the selection scope of breeding parents and incorporating the introduced varieties into future breeding programs. © 2014 Chinese Academy of Agricultural Sciences.

Liu X.,China West Normal University | Liu X.,Key Laboratory of Southwest China Wildlife Resources Conservation Ministry of Education | He S.,Nanchong Institute of Agricultural science | Zheng Z.,Nanchong Institute of Agricultural science | And 2 more authors.
African Journal of Biotechnology | Year: 2010

Grain rate (GR) is a very important trait in maize (Zea mays L.) breeding program related to yield. To realize its genetic basis, a recombinant inbred line (RIL) population and different nitrogen (N) regimes were used to map the quantitative trait loci (QTLs) for GR in maize. As a result, two QTLs were identified under high N regime and could explain a total of 14.84% of phenotypic variance. Due to additive effect, the QTL on chromosome 6 could decrease 0.029 of GR, while the QTL on chromosome 9 could increase 0.0203 of GR. Under low N regime, one QTL was mapped on chromosome 6 and could account for 9.52% of phenotypic variance, and owning to additive effect, the QTL could make GR decrease by 0.0234. The result in comparison with previous studies showed that the three QTLs in this present study were new quantitative loci associated with GR in maize. These results were beneficial for understanding the genetic basis of GR in maize. © 2010 Academic Journals.

Liu X.H.,China West Normal University | He S.L.,Nanchong Institute of Agricultural science | Zheng Z.P.,Nanchong Institute of Agricultural science | Tan Z.B.,Beijing IPE Bio technology Co. | And 2 more authors.
Genetics and Molecular Research | Year: 2011

Kernel number per ear (KNE) is one of the most important yield-related agronomic traits in maize (Zea mays). To clarify its genetic basis, we made a quantitative trait locus (QTL) analysis of KNE in a recombinant inbred line population derived from lines Mo17 and Huangzao4, under two nitrogen (N) regimes. Seven QTLs, on chromosomes 4, 6 and 9, were mapped under the high N regime, which explained phenotypic variation ranging from 5.03 to 15.49%. Under the low N regime, three QTLs were located on chromosomes 6 and 9, which accounted for phenotypic variation ranging from 8.54 to 12.21%. These QTLs had different mapping intervals to their nearest markers, ranging from 0 to 16.5 cM. According to the chromosome positions and genetic effects of these QTLs, only seven QTLs for KNE were identified in our experiment, out of which three were found under both N regimes, on chromosomes 6 (one) and 9 (two); the other four were mapped only under the high N regime, on chromosomes 4 (three) and 6 (one). This information could be useful for developing marker-assisted selection in maize-breeding projects. © FUNPEC-RP www.funpecrp.com.br.

Wu X.,Sichuan Agricultural University | Wu X.,Nanchong Institute of Agricultural science | Liu Y.,Sichuan Agricultural University | Liu Y.,Nanchong Institute of Agricultural science | And 12 more authors.
African Journal of Biotechnology | Year: 2011

A growth system was developed where N was the only growth-limiting factor. Whole-genome transcription profiling of leaf tissues were analyzed using the Affymetrix GeneChip. 129 clones showed significant change and 83 clones were classed accurately. Most induced clones were largely involved in various metabolism processes including physiological process, organelle regulation of biological process, nutrient reservoir activity, transcription regulator activity and multicellular organismal process. Putative high affinity nitrate transporter (nrt2.1) showed significant up-regulation under the severe low chronic nitrogen stress condition. Analysis of genes expression revealed several previously unidentified genes, including beta-D-glucosidase precursor gene (glu2), and Cyc3 cyclin3 gene. It suggests that under the said condition, nrt2.1 plays the most important role in N absorption and most of the other genes induced expression to enable the maize to have normal growth. A better understanding of the complex regulatory network for plant N responses among these genes will help and lead to improve N use efficiency. © 2011 Academic Journals.

Liu X.-H.,China West Normal University | Zheng Z.-P.,Nanchong Institute of Agricultural science | Tan Z.-B.,Beijing IPE Bio technology Co. | Li Z.,Nanchong Institute of Agricultural science | He C.,Nanchong Institute of Agricultural science
African Journal of Biotechnology | Year: 2010

100-kernel weight (KW) is one of the most important agronomic traits in maize (Zea mays L.), related to yield. To realize its genetic basis, in this study, a recombinant inbred line (RIL) population derived from the cross between Mo17 and Huangzao4 was used for quantitative trait locus (QTL) mapping for KW under high and low nitrogen (N) regimes. As a result, five QTLs were identified on chromosomes 3, 4, 7 and 9, of which three were detected under both N environments, while the other two QTLs were respectively detected under high and low N regimes. These QTLs could explain phenotypic variance from 4.47 to 14.47%. Due to additive effects, the three QTLs from Mo17, including two on chromosome 3 and one on chromosome 4, could increase KW from 0.64 to 1.01 g, while the other two from Huangzao4 on chromosomes 7 and 9 could decrease KW from 0.62 to 1.07 g. These results are beneficial for understanding the genetic basis of KW and developing the markers linked with KW for marker-assisted selection breeding in maize. © 2010 Academic Journals.

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