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1.
Increasing sugar content in silage maize stalk improves its forage quality and palatability. The genetic mapping and characterization of quantitative trait loci (QTLs) is considered a valuable tool for trait enhancement, yet little information on QTL for stalk sugar content in maize has been reported. To this end, we investigated QTLs associated with stalk sugar traits including Brix, plant height (PHT), three ear leaves area (TELA), and days to silking (DTS) in two environments using a population of 202 recombinant inbred lines from a cross between YXD053, which has a high stalk sugar content, and Y6-1, which has a low stalk sugar content. A genetic map with 180 SSR and 10 AFLP markers was constructed, which spanned 1,648.6 cM of the maize genome with an average marker distance of 8.68 cM, and QTLs were detected using composite interval mapping. Seven QTLs controlling Brix were mapped on chromosomes 1, 2, 6 and 9 in the combined environments. These QTLs could explain 2.69–13.08 % of the phenotypic variance. One major QTL for Brix on chromosome 2 located between the markers bnlg1909 and umc1635 explained 13.08 % of the phenotypic variance. Y6-1 also contributed QTL allele for increased Brix on chromosome 6. One major QTLs controlling PHT on chromosome 1 and TELA on chromosome 4 were also identified and accounted for 13.68 and 12.49 % of the phenotypic variance, respectively. QTL alleles for increased DTS were located on chromosomes 1 and 5 of YXD053. Significant epistatic effects were identified in four traits, but no significant QTL × environment interactions were observed. The information presented here may be valuable for stalk sugar content improvement via marker-assisted selection in silage maize breeding programs.  相似文献   

2.
Forage sorghum cultivars grown in India are susceptible to various foliar diseases, of which anthracnose, rust, zonate leaf spot, drechslera leaf blight and target leaf spot cause severe damage. We report here the quantitative trait loci (QTLs) conferring resistance to these foliar diseases. QTL analysis was undertaken using 168 F7 recombinant inbred lines (RILs) of a cross between a female parental line 296B (resistant) and a germplasm accession IS18551 (susceptible). RILs and parents were evaluated in replicated field trials in two environments. A total of twelve QTLs for five foliar diseases on three sorghum linkage groups (SBI-03, SBI-04 and SBI-06) were detected, accounting for 6.9–44.9% phenotypic variance. The morphological marker Plant color (Plcor) was associated with most of the QTL across years and locations. The QTL information generated in this study will aid in the transfer of foliar disease resistance into elite susceptible sorghum breeding lines through marker-assisted selection.  相似文献   

3.
To study the salt tolerance genetics of sorghum, 181 recombinant inbred lines (RILs) were used to locate quantitative trait loci (QTLs) underlying salt stress adaptability. Six traits, namely, plant height (PH), stem diameter (SD), total biomass (TB), stem fresh weight (SFW), juice weight (JW) and Brix, were investigated under normal and salt stress conditions in two years. A total of 53 QTLs for the six traits under both conditions and their corresponding salt tolerance index (STI) were detected and phenotypic variation explained (PVE) ranged from 4.16% to 20.42%. Six of the QTLs, qTB6, qSFW9, qJW9, qBrix2, qBrix10 and qSTI-Brix9, were the main effect QTLs controlling salt tolerance and had a PVE more than 10%. qSFW9 and qJW9 colocalized in the same marker interval as SB5069-UGSM18 and had PVEs of 17.70% and 14.20%, respectively, with positive effects from L-Tian. QTL clusters controlling PH, TB, STI-TB, SFW and JW were consistently mapped in the marker interval of Xcup19-SB4177 on chromosome 7. These locations might serve as target sites for marker-assisted selection (MAS) in improving salt tolerance of sorghum.  相似文献   

4.
Sweet sorghum (Sorghum bicolor [L.] Moench) is a prospective bioethanol feedstock source. Four high-biomass and sweet sorghum male lines and three grain sorghum female lines were intercrossed using Design II mating. Parents and hybrids were evaluated to (a) identify genetic sources to improve biofuel traits, and (b) determine the inheritance of biofuel and morpho-agronomic traits. Total soluble sugars (TSS) per plant were determined using juice weight (JW) and Brix (°Bx). Plant height (PH), biomass (BM) and stalk diameter (SD) were also measured. Mean hybrid performance for PH, JW, TSS and BM was higher than the male parent means. Three male parents exhibited positive and significant general combining ability (GCA) for at least three traits. Among males, PI185672 showed the highest GCA for PH, °Bx and BM, while No. 08 exhibited the greatest GCA for JW and TSS. Most hybrids exhibited overdominance-driven high-parent heterosis for all traits except SD. Trait broad-sense heritability ranged from 0.71 (BM) to 0.93 (PH). Results revealed that biofuel traits could be substantially improved through breeding, which will contribute to enhanced bioethanol production.  相似文献   

5.
贺亚军  吴道明  傅鹰  钱伟 《作物学报》2018,44(4):533-541
株高是油菜重要的农艺性状之一。以油菜品种Express、SWU07构建的包含261个株系的DH群体和由其构建的包含234个株系的IF2群体为材料, 分析2年环境下株高及其相关性状QTL表明, 在2个群体的各年份环境中总共检测到41个株高及其相关性状QTL, 分布于甘蓝型油菜的13条染色体上, 其中9个与株高相关的QTL, 分布于A02、A09、C01、C02和C06连锁群, 分别揭示了3.85%~13.34%的表型变异, 15个与主花序长度相关的QTL, 分布于A01、A02、A05、A08、A09、C01、C03和C05连锁群, 分别揭示了3.82%~9.52%的表型变异; 11个与第1分枝高度相关的QTL, 分布于A01、A03、A09、C01和C03连锁群, 分别揭示了4.01%~16.54%的表型变异; 4个与分枝区段长相关的QTL, 分布于甘蓝型油菜的A07、A09、C03和C04连锁群, 揭示了4.79%~8.10%的表型变异; 2个与平均节间长相关的QTL, 分布于A07和C05连锁群, 分别揭示了4.29%~6.04%的表型变异。其中5个QTL在不同年份环境或不同群体中被重复检测到。这些QTL为油菜株高的遗传改良提供了有用的信息。  相似文献   

6.
The objective of this study was to identify quantitative trait loci (QTLs) controlling 100‐seed weight in soybean using 188 recombinant inbred lines (RIL) derived from a cross of PI 483463 and ‘Hutcheson’. The parents and RILs were grown for 4 years (2010–2013), and mature, dry seeds were used for 100‐seed weight measurement. The variance components of genotype (a), environment (e) and a × e interactions for seed weight were highly significant. The QTL analysis identified 14 QTLs explaining 3.83–12.23% of the total phenotypic variation. One of the QTLs, qSW17‐2, was found to be the stable QTL, being identified in all the environments with high phenotypic variation as compared to the other QTLs. Of the 14 QTLs, 10 QTLs showed colocalization with the seed weight QTLs identified in earlier reports, and four QTLs, qSW5‐1, qSW14‐1, qSW15‐1 and qSW15‐2, found to be the novel QTLs. A two‐dimensional genome scan revealed 11 pairs of epistatic QTLs across 11 chromosomes. The QTLs identified in this study may be useful in genetic improvement of soybean seed weight.  相似文献   

7.
Fiber yield and yield components – including lint index (LI), seed index (SI), lint yield (LY), seed cotton yield (SCY) and number of seeds per boll (NSPB) – were investigated on the farm of Huazhong Agricultural University in a population of 69 F2 individuals and corresponding F2:3 families derived from a cross between high-fiber-yield Gossypium hirsutum CV Handan 208 and a low-fiber-yield Gossypium barbadense CV Pima 90. On the basis of the genetic map constructed previously from the same population by Lin et al. (Plant Breed., 2005), quantitative trait locus (QTL) analysis was performed with the software QTL Cartographer V2.0 using composite interval mapping method (LOD ≥ 3.0). A total of 21 QTLs were identified, which were located in 15 linkage groups. The number of QTLs per trait ranged from one to seven. Of these QTLs detected, one affecting LI explained 24.3% of phenotypic variation (PV), five influencing SI explained 16.15–39.21% of PV, seven controlling LY explained 13.01–28.35% of PV, and two controlling SCY explained 22.76 and 39.97% of PV, respectively. Simultaneously, the detected six QTLs for NSPB were located on five linkage groups, which individually explained 28.01–38.32% of the total phenotypic variation. The results would give breeders further insight into the genetic basis of fiber yield.  相似文献   

8.
Salt tolerance of rice (Oryza sativa L.) at the seed germination stage is one of the major determinants for the stable stand establishment in salinity soil. One population of recombinant inbred lines (RILs, F2:9), derived from a cross between a japonica rice landrace tolerant to salt stress and a sensitive indica rice variety, was used to determine the germination traits including imbibition rate and germination percentage under control (water) and salt stress (100 mM NaCl) for 10 days at 30 °C. The multiple interval mapping (MIM) were applied to conduct QTL for the traits. The results showed that seed germination was a quantitative trait controlled by several genes, and strongly affected by salt stress. A total of 16 QTLs were detected in this study, and each QTL could explain 4.6–43.7% of the total phenotypic variance. The expression of these QTLs might be developmentally regulated and growth stage-specific. In addition, only one digenic interaction was detected under salt stress, showing small effect on germination percentage with R2 2.7%. Among sixteen QTLs detected in this study, four were major QTLs with R2 > 30%, and some novel alleles of salt tolerance genes in rice. The results demonstrated that the japonica rice Jiucaiqing is a good source of gene(s) for salt tolerance and the major or minor QTLs identified could be used to improve the salt tolerance by marker-assisted selection (MAS) in rice.  相似文献   

9.
Drought tolerance was investigated in ‘C306’, one of the most drought tolerant wheat cultivars bred in India in the 1960’s. An intervarietal mapping population of recombinant inbred lines of the cross ‘C306’ × ‘HUW206’ was evaluated for drought tolerance components, namely potential quantum efficiency of photosystem (PS) II (Fv/Fm), chlorophyll content (Chl), flag leaf temperature (Lt), and grain yield per plant (Gyp) under stress. Three independent experiments were conducted under well-watered and water-stressed conditions in greenhouses and growth chambers at Kansas State University (USA). Five hundred and sixty microsatellite markers covering the entire genome were screened for polymorphism between the parents. A QTL (QLt.ksu-1D) for Lt (low flag leaf temperature under stress) on the short arm of chromosome 1D between markers Xbarc271 and Xgwm337 at LOD 3.5 explained 37% of the phenotypic variation. A QTL for Fv/Fm (QF v /F m .ksu-3B) and Chl (QChl.ksu-3B) controlling quantum efficiency of PS II and chlorophyll content under stress were co-localized on chromosome 3B in the marker interval Xbarc68–Xbarc101 and explained 35–40% of the phenotypic variation for each trait. A QTL (QGyp.ksu-4A) for Gyp on chromosome 4A at a LOD value of 3.2 explained 16.3% of the phenotypic variation. Inconsistent QTLs were observed for Fv/Fm on chromosomes 3A, 6A, 2B, 4B, and 4D; for Chl on 3A, 6A, 2B and 4B; and for Lt on 1A, 3A 6A, 3B and 5B. The identified QTLs give a first glimpse of the genetics of drought tolerance in C306 and need to be validated in field experiments using the marker-phenotype linkages reported here.  相似文献   

10.
This study was conducted to identify quantitative trait loci (QTLs) for drought tolerance in sorghum (Sorghum bicolor (L.) Moench) by association mapping using a simple sequence repeat (SSR)-marker-based diversity research set. Genotypic data for 98 SSR marker loci on ten chromosomes were used for the association analysis. The experiment was conducted under control (well-watered) and drought stress conditions, and the phenotypic values of 23 morphological traits were recorded. Drought tolerance was assessed by using a leaf drying score as a parameter of the tolerance/susceptibility: scores were assigned on a scale from 1 (most tolerant) to 9 (most susceptible). Under the control conditions, 17 QTLs associated with 12 traits were identified on chromosomes 1, 2, 4, 8, 9, and 10, with ?Log10 (P) ranging from 2.5 to 7.6 and explaining 9.5–57.5 % of the total phenotypic variance for the traits. Under the drought stress conditions, nine QTLs associated with 8 traits were identified on chromosomes 1, 2, 3, and 10 that explained 9–61.2 % of the total phenotypic variance for the traits, with ?Log10 (P) ranging from 2.5 to 3.5. QTLs for some traits were detected only under the drought stress condition, suggesting that these traits are important in drought tolerance. These QTLs could be used to further dissect the genetic and physiological basis of drought tolerance in sorghum.  相似文献   

11.
Disease resistance is a sought-after trait in plant breeding programmes. One strategy to make resistance more durable is to increase the number of resistance genes, thereby increasing the number of pathotypes withstood. One of the most important diseases on roses is powdery mildew (PM) (Podosphaera pannosa). Recent studies show that pathotypes of PM and different types of resistances in roses exist. The results of this study aim to contribute to PM resistance in roses by the development of pathotype-specific markers on a genetic map. A diploid rose population (90 genotypes) derived from a cross between Rosa wichurana and Rosa ‘Yesterday’ was used to construct a genetic linkage map encompassing 20 AFLP primer combinations, 43 SSR, and 2 morphological markers. By applying the F1 pseudo test cross population strategy, two parental linkage maps were constructed (parent ‘Yesterday’ 536 cM; parent R. wichurana 526 cM). Both parental maps consisted of seven linkage groups with an average length of 70 cM (Kosambi) corresponding to the seven haploid rose chromosomes. These new maps were used to identify QTLs controlling disease resistance. The offspring population was screened for resistance to two PM pathotypes, R–E and R–P. QTLs for controlling pathotype-specific disease resistance were mapped by applying Kruskal–Wallis rank-sum tests and simple interval mapping. With two pathotypes analysed, nine QTL loci were detected on linkage groups 2, 3, 5 and 6, explaining 15–73% of the phenotypic variance for pathotype-specific disease response. The genetic maps developed here will be useful for future rose breeding, pathotype-specific resistance research and development of a consensus map for roses.  相似文献   

12.
Chromium contamination in soil has become a severe threat to crop production and food safety. The experiment was conducted using a rice DH population to detect the QTLs associated with Cr tolerance. Seventeen putative QTLs associated with growth traits included three additive loci and fourteen epistatic loci. These loci were distributed on 11 rice chromosomes, and their contribution to the phenotypic variation ranged from 2.44 to 10.08%. Two QTLs located at the similar genetic region on chromosome ten were associated with shoot Cr concentration and translocation from roots to shoots, respectively; and they accounted for 11.65 and 11.22% of the phenotypic variation. In addition, six QTLs related to Zn concentration and translocation was found on chromosomes 1, 2, 4, 5, 7 and 12. Meanwhile epistatic effect existed in the two additive QTLs of qRZC1 and qRZC7. Most of QTLs controlling Zn concentration had small genotypic variance and qSRZ4 related to Zn translocation showed growth condition-dependent expression.  相似文献   

13.
Mapping QTLs in breeding for drought tolerance in maize (Zea mays L.)   总被引：13，自引：0，他引：13  
Summary Grain yield in the maize (Zea mays L) plant is sensitive to drought in the period three weeks either side of flowering. Maize is well-adapted to the use of restriction fragment length polymorphisms (RFLPs) to identify a tight linkage between gene(s) controlling the quantitative trait and a molecular marker. We have determined the chromosomal locations of quantitative trait loci (QTLs) affecting grain yield under drought, anthesis-silking interval, and number of ears per plant. The F3 families derived from the cross SD34(tolerant) × SD35 (intolerant) were evaluated for these traits in a two replicated experiment. RFLP analysis of the maize genome included non-radioactive DNA-DNA hybridization detection using chemiluminescence. To identify QTLs underlying tolerance to drought, the mean phenotypic performances of F3 families were compared based on genotypic classification at each of 70 RFLP marker loci. The genetic linkage map assembled from these markers was in good agreement with previously published maps. The phenotypic correlations between yield and other traits were highly significant. In the combined analyses, genomic regions significantly affecting tolerance to drought were found on chromosomes 1,3,5,6, and 8. For yield, a total of 50% of the phenotypic variance could be explained by five putative QTLs. Different types of gene action were found for the putative QTLs for the three traits.  相似文献   

14.
Grain size is a main component of rice appearance quality. In this study, we performed the SSR mapping of quantitative trait loci (QTLs) controlling grain size (grain length and breadth) and shape (length/breadth ratio) using an F2 population of a cross between two Iranian cultivars, Domsephid and Gerdeh, comprising of 192 individuals. A linkage map with 88 markers was constructed, which covered 1367.9 cM of the rice genome with an average distance of 18 cM between markers. Interval mapping procedure was used to identify the QTLs controlling three grain traits, and QTLs detected were further confirmed using composite interval mapping. A total of 11 intervals carrying 18 QTLs for three traits were identifed, that included five QTLs for grain length, seven QTLs for grain breadth, and six QTLs for grain shape. A major QTL for grain length was detected on chromosome 3, that explained 19.3% of the phenotypic variation. Two major QTLs for grain breadth were mapped on chromosomes 3 and 8, which explained 34.1% and 20% of the phenotypic variation, respectively. Another two major QTLs were identified for grain shape on chromosomes 3 and 8, which accounted for 27.1% and 20.5% of the phenotypic variance, respectively. The two QTLs that were mapped for grain shape coincided with the major QTLs detected for grain length and grain breadth. Intrestingly, gs2 QTL specific to grain shape was detected on chromosome 2 that explained 15% of the phenotypic variation.  相似文献   

15.
The indica variety Dular has a high level of resistance to rice stripe virus (RSV). We performed quantitative trait locus (QTL) analysis for RSV resistance using 226 F2 clonal lines at the seedling stage derived from a cross between the susceptible japonica variety Balilla and the resistant indica variety Dular with two evaluation criteria, infection rate (IR) and disease rating index (DRI). The experiments were performed in both 2004 and 2005. Based on IR, three putative QTLs were detected and had consistent locations in the 2 years, one QTL was detected in the RM7324–RM3586 interval on chromosome 3. The other two QTLs were linked and located in the RM287–RM209 and RM209–RM21 intervals on the long arm of chromosome 11, and accounted for 87.8–57.8% of the total phenotypic variation in both years. Based on DRI, three putative QTLs were also detected and had consistent locations in both years. One of them was located in the RM1124–SSR20 interval on the short arm of chromosome 11, while the other two linked QTLs had the same chromosomal locations on chromosome 11 as those detected by IR, and accounted for 55.7–42.9% of total phenotypic variation in both years. In comparison to the mapping results from previous studies, one of the two linked QTLs had a chromosomal location that was similar to Stv-b i , an important RSV resistance gene, while the other appeared to be a newly reported one.  相似文献   

16.
Sorghum is one of the most important cereal crops; it is used to produce feed, sugar, and biofuel. To investigate genetic tradeoffs between grain and stem sugar production, we evaluated plant height, Brix (the percentage of soluble solids in stalk juice), 100-grain weight and flowering time over 3 years in a recombinant inbred line (RIL) population consisting of 189 individuals derived from a cross between the sweet sorghum cultivar ‘Rio’ and grain sorghum ‘BTx623’. We constructed a genetic linkage map (total length, 1418.71 cM; average distance between markers, 11.26 cM), which consisted of 118 simple sequence repeat (SSR) and 8 insertion-deletion (INDEL) markers. A total of 14 QTLs were detected on chromosomes 1, 3, 6, 7, and 9, which included 6 QTLs for plant height; 4 for Brix; and 2 QTLs for each 100-grain weight and flowering time. Eight QTLs were detected at least in 2 years. These results will be useful for future QTL fine mapping and gene mining for these traits, and useful for the improvement of sorghum through molecular marker-assisted selection.  相似文献   

17.
研究盐胁迫、干旱胁迫下甘蓝型油菜的发芽率,寻找与发芽率相关联的分子标记,可为油菜逆境胁迫下种子萌发的分子标记辅助育种提供理论依据。本研究以甘蓝型黄籽油菜GH06和甘蓝型黑籽油菜P174为亲本,通过单粒传法(single seed descent, SSD)连续自交9代构建重组自交系群体。采用16 g L–1的NaCl溶液进行盐胁迫,20% (W/W)的PEG-6000溶液模拟干旱胁迫,处理重组自交系种子并统计其发芽率。实验室构建的SNP遗传图谱,包含2795个SNP多态性标记位点,总长1832.9 cM,相邻标记间平均距离为0.66 cM,利用该图谱并采用复合区间作图法(CIM)分析两种胁迫条件下第3天、第4天及累计4 d后发芽率的QTL。共检测到19个QTL,分布于A01、A03、A06、A07、A09和C06染色体上。其中,11个盐胁迫相关的QTL可解释的变异为4.9%~10.9%,8个干旱胁迫相关的QTL可解释的变异为3.8%~6.9%;并且在A03和A09染色体上,盐胁迫和干旱胁迫下检测到的QTL有相近区段。研究结果表明油菜种子发芽率属于典型的数量性状,受环境影响较大;且随着胁迫时间的延长,油菜种子启动了不同的基因来响应环境胁迫。  相似文献   

18.
This study aimed at developing, characterizing and evaluating two maize phenotypic‐selected introgression libraries for a collection of dominant plant height (PHT)‐increasing alleles by introgressing donor chromosome segments (DCS) from Germplasm Enhancement of Maize (GEM) accessions into elite inbred lines: PHB47 and PHZ51. Different backcross generations (BC1‐BC4) were developed and the tallest 23 phenotype‐selected introgression families (PIFs) from each introgression library (PHB47 or PHZ51) were selected for single nucleotide polymorphism genotyping to localize DCS underlying PHT. The result shows that most PIFs carrying DCS were significantly (α = 0.01) taller than the respective recurrent parent. In addition, they contained larger donor genome proportions than expected in the absence of selection or random mating across all BC generations. The DCS were distributed over the whole genome, indicating a complex genetic nature underlying PHT. We conclude that our PIFs are enriched for favourable PHT‐increasing alleles. These two libraries offer opportunities for future PHT gene isolation and allele characterization and for breeding purposes, such as novel cultivars for biofuel production.  相似文献   

19.
Water shortage and heterogeneity in precipitation constitute the essential limiting factors for agricultural production in the Mediterranean basin. To understand the complex inheritance of tolerance to drought stress in Medicago truncatula, quantitative trait loci (QTLs) analysis was performed using a set of recombinant inbred lines (RILs) derived from a cross between the susceptible line Jemalong A17 and the tolerant line F83005.5. We conducted two experiments where the RILs and parental lines were grown in 0 mM and 75 mM of mannitol (D-) in tubes and in control and 33% of the field capacity (FC) in pots. In both experiments, line and line by water treatment interaction were significant. QTLs analysis showed that several putative genomic regions are involved in the variation of measured traits under the two water treatments in tubes and pots. A total of 21 QTLs on 8 linkage groups were detected for the measured traits in both experiments, 11 of them were in tubes conditions. Eight of these 11 QTLs were identified in control treatment and three in mannitol. While the number of QTLs identified in tubes under control conditions was more than under mannitol conditions, the highest number of QTLs was detected in water-stressed conditions in pots. The percentage of phenotypic variance explained by a single QTL (R 2) ranges from 11.7 to 26.3% in tubes and from 11.2 to 18.4% in pots depending on the trait, with 6 QTLs in each condition explaining <15% of the phenotypic variance. The number of common QTLs under two water treatments was one for length of stems (LS), number of internodes (NIN) and aerial dry weight (ADW) in tubes, and zero for NIN and one for LS and leaf area (LA) in pots. However, a few overlapping QTLs were found in tubes and pots on linkage groups 5 and 7 for LS and NIN.  相似文献   

20.
定位棉花种子性状的基因对揭示棉花种子性状的遗传规律,以及明确棉花种子、产量、纤维品质等性状间的遗传关系具有重要意义。以(渝棉1号×T586) F2:7重组近交系群体构建的遗传连锁图谱,在鉴定270个家系3个环境种子物理性状的基础上,利用MQM作图方法,共检测到34个种子物理性状QTL,包括9个种子重(qSW)、5个短绒重(qFW)、3个短绒率(qFP)、8个种仁重(qKW)、6个种子壳重(qHW)和3个种仁率(qKP)QTL,它们可解释4.6%~80.1%的性状表型变异。9个QTL在2个或3个环境中被检测到,其中包括第12染色体显性光子位点的短绒重与短绒率QTL,以及另外7个微效应QTL。34个QTL分布于15条染色体,其中A染色体组20个,D染色体组14个。有12个染色体区段分布有2个或2个以上的QTL,而且同一染色体区域同一亲本所具有的不同性状QTL的方向大多数与性状表型相关系数的正负一致。  相似文献   

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