[Show abstract][Hide abstract] ABSTRACT: Production of mutants with altered phenotypes is a powerful approach for determining the biological functions of genes in an organism. In this study, a high high-grain-weight mutant line M8008 was identified from a library of mutants of the common wheat cultivar YN15 treated with ethylmethane sulfonate (EMS). F2 and F2:3 generations produced from crosses of M8008 × YN15 (MY) and M8008 × SJZ54 (MS) were used for genetic analysis. There were significant differences between M8008 and YN15 in plant height (PH), spike length (SL), fertile spikelet number per spike (FSS), grain width (GW), grain length (GL), GL/GW ratio (GLW), and thousand-grain weight (TGW). Most simple correlation coefficients were significant for the investigated traits, suggesting that the correlative mutations occurred in M8008. Approximately 21% of simple sequence repeat (SSR) markers showed polymorphisms between M8008 and YN15, indicating that EMS can induce a large number of mutated loci. Twelve quantitative trait loci (QTLs) forming QTL clusters (one in MY and two in MS) were detected. The QTL clusters coinciding with (MY population) or near (MS population) the marker wmc41 were associated mainly with grain-size traits, among which the M8008 locus led to decreases in GW, factor form density (FFD), and TGW and to increases in GLW. The cluster in the wmc25 − barc168 interval in the MS population was associated with yield traits, for which the M8008 locus led to decreased PH, spike number per plant (SN), and SL.
[Show abstract][Hide abstract] ABSTRACT: Aims
Potassium (K) is one of the most important mineral nutrients limiting plant growth in agricultural systems. This study investigated the effects of low-K treatments and detected quantitative trait loci (QTLs) for K efficiency traits at the seedling and adult stages of wheat.
Eleven seedling traits under a hydroponic culture trial with five K treatments and nine adult traits in a pot trial and a field trial with three K treatments were investigated using a set of wheat recombinant inbred lines (RILs).
Values of most of the seedling and adult traits decreased with decreasing K supply, but the K-use efficiency and ratio of dry weight between seedling roots and shoots (RSDW) increased. A total of 87 QTLs for seedling traits in the hydroponic culture trial and 51 and 29 QTLs for adult traits in the pot and field trials, respectively, were detected. We also identified 15 relatively high-frequency QTLs (RHF-QTLs) which can be detected in over half of the treatments and 21 QTL clusters which is defined as the co-location of QTLs for more than two traits.
K efficiency traits and the related QTLs of wheat were greatly affected by K treatments. Several relatively stable QTLs and important QTL clusters may be potential targets for marker-assisted selection for wheat nutrient efficiency.
Plant and Soil 12/2013; 373(1-2). DOI:10.1007/s11104-013-1844-4 · 2.95 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Glutamine synthetase (GS) is a key enzyme in the formation of the amino acid glutamine during N assimilation. The characterization of GS genes and the development of functional markers are important for marker-assisted selection (MAS) in wheat breeding programs. In the present study, the full-length genomic DNA (gDNA) sequence of TaGS1a was obtained from 60 wheat varieties. TaGS1a comprises 3415 bp and has eleven exons and ten introns. Nine single nucleotide polymorphisms (SNPs) and two insertions and deletions of DNA segments (InDels) were detected in introns, resulting two haplotypes: Hap 1 and Hap 2. A cleaved amplified polymorphic sequence (CAPS) marker was developed to distinguish the two haplotypes. The TaGS1a-CAPS marker was located on chromosome 6D using Chinese Spring nullisomic-tetrasomic lines, and mapped at 2.5 cM from the SSR marker barc1121b in a RIL population. The completely corresponding results between quantitative trait locus (QTL) analysis and association analysis suggested that the TaGS1a gene had functions for grain size traits, including thousand grain weight (TGW), grain width (GW), grain height (GH), GL/GW ratio (GLW), factor form density (FFD), grain area (GA) and grain volume (GV) during maturity stage, and for the ratio of root/shoot for dry weight and nitrogen, phosphorus, potassium contents (RSDW, RSNC, RSPC and RSKC) during seedling stage.
Field Crops Research 12/2013; 154:119-125. DOI:10.1016/j.fcr.2013.07.012 · 2.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The uptake and utilization of nitrogen (N) by plants are affected by the different forms of N in the soil. In this study, eight morphological traits at the seedling stage were investigated using a set of recombinant inbred lines (RILs). Three hydroponic culture experiments were conducted using three different NO3−/NH4+ ratios (T1 at 50/50 %, T2 at 100/0 % and T3 at 0/100 %). The investigated traits in T2 and T1 were significantly higher than T3 in all three experiments, indicating that NO3− promoted or NH4+ suppressed the production of biomass. Comparing T1 with T2, NO3− significantly increased the values of root fresh weight (RFW), total fresh weight (TFW) and root dry weight (RDW) and significantly decreased shoot dry weight (SDW). A total of 147 quantitative trait loci (QTLs) for the eight traits were detected on 18 chromosomes (except 2A, 3D and 4D). Among them, 16 QTLs (QRfw-1A, QRfw-1D, QSfw-1D, QSfw-2B.1, QTfw-1A, QTfw-1D, QRsfw-2B, QRsfw-3B.1, QRdw-1A.1, QRdw-1A.2, QSdw-6B.1, QSdw-7A.1, QTdw-1A.1, QRsdw-1A.1, QRsdw-5A.1 and QRsdw-7A.1) were detected in more than three of the nine treatment–experiments, and most of the 16 QTLs made large contributions of approximately 15 %. Surprisingly, QRsfw-4A.1 and QRsfw-4A.2 explained as much as 47.9 and 55.5 % of the phenotypic variation, respectively. Thirteen important QTL clusters (C1-C13) with more than four QTLs and involving 66 QTLs (44.9 %) were mapped on chromosomes 1A, 1D, 2B, 2D, 4A, 4B, 5B, 5D, 6B, 7A and 7B.
[Show abstract][Hide abstract] ABSTRACT: Nutrient use efficiency (NuUE), comprising nutrient uptake and utilization efficiency, is regarded as one of the most important factors for wheat yield. In the present study, six morphological, nine nutrient content and nine nutrient utilization efficiency traits were investigated at the seedling stage using a set of recombinant inbred lines (RILs), under hydroponic culture of 12 treatments including single nutrient levels and two- and three-nutrient combinations treatments of N, P and K. For the 12 designed treatments, a total of 380 quantitative trait loci (QTLs) on 20 chromosomes for the 24 traits were detected. Of these, 87, 149 and 144 QTLs for morphological, nutrient content and nutrient utilization efficiency traits were found, respectively. Using the data of the average value (AV) across 12 treatments, 70 QTLs were detected for 23 traits. Most QTLs were located in new marker regions. Twenty-six important QTL clusters were mapped on 13 chromosomes, 1A, 1B, 1D, 2B, 3A, 3B, 4A, 4B, 5D, 6A, 6B, 7A and 7B. Of these, ten clusters involved 147 QTLs (38.7%) for investigated traits, indicating that these 10 loci were more important for the NuUE of N, P and K. We found evidence for cooperative uptake and utilization (CUU) of N, P and K in the early growth period at both the phenotype and QTL level. The correlation coefficients (r) between nutrient content and nutrient utilization efficiency traits for N, P and K were almost all significantly positive correlations. A total of 32 cooperative CUU loci (L1-L32) were found, which included 190 out of the 293 QTLs (64.8%) for the nutrient uptake and utilization efficiency traits, indicating that the CUU-QTLs were common for N, P and K. The CUU-QTLs in L3, L7, L16 and L28 were relatively stable. The CUU-QTLs may explain the CUU phenotype at the QTL level.
[Show abstract][Hide abstract] ABSTRACT: DArT and SSR markers were used to saturate and improve a previous genetic map of RILs derived from the cross Chuan35050 × Shannong483. The new map comprised 719 loci, 561 of which were located on specific chromosomes, giving a total map length of 4008.4 cM; the rest 158 loci were mapped to the most likely intervals. The average chromosome length was 190.9 cM and the marker density was 7.15 cM per marker interval. Among the 719 loci, the majority of marker loci were DArTs (361); the rest included 170 SSRs, 100 EST-SSRs, and 88 other molecular and biochemical loci. QTL mapping for fatty acid content in wheat grain was conducted in this study. Forty QTLs were detected in different environments, with single QTL explaining 3.6-58.1% of the phenotypic variations. These QTLs were distributed on 16 chromosomes. Twenty-two QTLs showed positive additive effects, with Chuan35050 increasing the QTL effects, whereas 18 QTLs were negative with increasing effects from Shannong483. Six sets of co-located QTLs for different traits occurred on chromosomes 1B, 1D, 2D, 5D, and 6B.
[Show abstract][Hide abstract] ABSTRACT: Quality traits in wheat (Triticum aestivum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050×Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99–40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.
[Show abstract][Hide abstract] ABSTRACT: Quantitative trait locus (QTL) analysis of kernel shape and weight in common wheat was conducted using a set of 131 recombinant
inbred lines (RIL) derived from ‘Chuan 35050’×‘Shannong 483’. The RIL and their two parental genotypes were evaluated for
kernel length (KL), kernel width (KW), thousand-kernel weight (TKW), and test weight (TW) in four different environments.
Twenty QTL were located on 12 chromosomes, 1A, 1B, 1D, 2A, 2B, 3B, 4A, 4B, 5D, 6A, 6B, and 7B, with single QTL in different
environments explaining 5.9–26.4% of the phenotypic variation. Six, three, four, and seven QTL were detected for KL, KW, TKW,
and TW, respectively. The additive effects for 17 QTL were positive with Chuan 35050 increasing the QTL effects, whereas the
remaining three QTL were negative with Shannong 483 increasing the effects. Eight QTL (40%) were detected in two or more environments.
Two QTL clusters relating to KW, TKW, and TW were located on chromosomes 2A and 5D, and the co-located QTL on chromosome 6A
involved a QTL for KW found in two environments and a QTL for TKW detected in four environments.