Mapping QTLs for tissue culture response in soybean (Glycine max (L.) Merr.).
ABSTRACT Quantitative trait loci (QTLs) that control the tissue culture response in soybean were detected by using 184 recombinant inbred lines (RILs) derived from two varieties: Kefeng No.1 and Nannong 1138-2. The molecular map consisting of 834 molecular markers using this population covered space 2307.83 cM of the genome throughout 24 linkage groups. The performance of tissue culture in soybean was evaluated by two indices: callus induction frequency (CIF) and somatic embryos initiation frequency (SEIF). They were expressed as the number of explants producing callus/ the number of total explants and the number of explants producing somatic embryos/ the number of total explants, respectively. The RIL lines showed continuous segregation for both indices. With the composite interval mapping (CIM) described in Windows QTL Cartographer Version 2.5, three quantitative trait loci (QTLs) were identified for the frequency of callus induction, on chromosomes B2 and D2, accounting for phenotypic variation from 5.84% to 16.60%; four QTLs on chromosome G were detected for the frequency of somatic embryos initiation and explained the phenotypic variation from 7.79% to 14.16%. The information of new QTLs identified in the present study will contribute to genetic improvement of regeneration traits with marker-assisted selection (MAS) in soybean.
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ABSTRACT: The current study was conducted to identify random amplified polymorphic DNA (RAPD) markers linked to genes controlling somatic embryogenesis in alfalfa. Segregation analyses of the somatic embryogenesis trait and the RAPD markers in an F1 population of 83 plants, derived from a cross between embryogenic A70-34 and non-embryogenic Arrow36 alfalfa plants, identified a polymorphic band that is associated with somatic embryogenesis. Based on the assumptions that somatic embryogenesis in alfalfa is controlled by two dominant genes with complementary effects and that the genotypes of A70-34 and Arrow36 are AAaaBbbb and aaaabbbb, respectively, the segregation data for the marker and the somatic embryogenesis trait in the F1s indicate that the marker is linked to the A locus. The maximum recombination fraction estimated for the linkage between the marker and the gene is 36.3%.Plant Molecular Biology 06/1993; 22(2):269-77. · 3.52 Impact Factor
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ABSTRACT: The mature wheat embryo is arguably one of the best explants for genetic transformation because of its unlimited availability and lack of growth season restriction. However, an efficient regeneration system using mature wheat embryos (Triticum aestivum L.) is still not available. To identify genes related to the tissue culture response (TCR) of wheat, QTLs for callus induction from mature embryos and callus regeneration were mapped using an RIL population derived from the cross of "Wangshuibai" with "Nanda2419" which has a good TCR. By whole genome scanning we identified five, four and four chromosome regions conditioning, respectively, percent embryos forming a callus (PEFC), percent calli regenerating plantlets (PCRP), and number of plantlets per regenerating callus (NPRC). The major QTLs QPefc.nau-2A and QPcrp.nau-2A were mapped to the long arm of chromosome 2A, explaining up to 22.8% and 17.6% of the respective phenotypic variance. Moreover, two major QTLs for NPRC were detected on chromosomes 2D and 5D; these together explained 51.6% of the phenotypic variance. We found that chromosomes 2A, 2D, 5A, 5B and 5D were associated via different intervals with at least two of the three TCR indexes used. Based on this study and other reports, the TCRs of different explant types of wheat may be under the control of shared or tightly linked genes, while different genes or gene combinations may govern the stages from callus induction to plantlet regeneration. The importance of group 2 and 5 chromosomes in controlling the TCRs of Triticeae crops and the likely conservation of the corresponding genes in cereals are discussed.Molecules and Cells 07/2007; 23(3):323-30. · 2.21 Impact Factor
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ABSTRACT: A quantitative trait loci (QTL) analysis for androgenetic capability has been conducted on three different crosses in maize, including very high and nonresponding lines for androgenesis. The doubled haploid lines derived by anther culture from the crosses DH5 x DH7, A188 x DH7, and R6 x DH99 showed a range of 0-70%, 0-40%, and 0-50% androgenetic responding anthers, respectively. The genotypic heritability of means for this trait is close to 0.90 for A188 x DH7 and 0.78 for R6 x DH99. The QTL analysis involved in each population the mapping of more than 100 loci covering a large part of the genome with reasonably spaced markers averaging 12 cM. Different measurements describing the androgenetic process were studied: AC, percentage of responding anthers; ELS, number of androgenetic embryos produced per 100 plated anthers; PLE, number of plantlets regenerated per 100 embryos; PLA, number of plantlets per 100 plated anthers. In each cross, three to four QTLs were found for AC, explaining 30-40% of the phenotypic variation. The QTL detected for PLA was also strong QTL for AC or ELS. This agrees with the observation that these last two traits are good predictors for final plantlet yield. The QTLs found were specific, although the same line DH7 was used in two crosses and DH99 derived from DH5 and DH7 in the third cross. These results suggest that the transfer of the androgenetic capabilities in elite germplasm will still involve a phenotypic evaluation of the androgenetic performances. A backcross-assisted selection based only on the genotype at the QTL is probably possible but only within the crosses used for this QTL analysis.Genome 01/1995; 37(6):970-6. · 1.67 Impact Factor