Effect of three anthocyaninless genes on germination in tomato (Lycopersicon esculentum Mill.) II. Seed germination under stress conditions

Seeds from four pairs of tomato isogenic/near-isogenic lines (IL/NIL) differing for anthocyaninless of Hoffmann (ah), three pairs of IL/NILs differing for anthocyaninwithout (aw) and six pairs of IL/NILs differing for baby lea syndrome (bls) were evaluated for their germination ability under stress conditions: low and high temperature, salt and osmotic stress. Mutant genes affecting anthocyanin biosynthesis enhanced tomato germination capacity under all above mentioned treatments, except for the aw gene under a PEG-6000 treatment. Testa removal accelerated germination under stress conditions, but differences in time to 50% germination between the wild type lines and their ah-, aw- and bls-IL/NILs although diminished, were not eliminated. This revised version was published online in July 2006 with corrections to the Cover Date.     

Anthocyanin mutations improving tomato and pepper tolerance to adverse climatic conditions

The effect of four mutated genes affecting anthocyanin biosynthesis was investigated relative to tomato and pepper germination capacities and early seedlings and plantlets growth. The study was performed on isogenic/near isogenic lines (IL/NIL) differing for genes ah (Hoffmann’s anthocyaninless), aw (anthocyanin without) and bls (babylea syndrome) in tomato and al ₁ (anthocyaninless – 1) in pepper. Germination responses of the IL/NILs showed that genes ah, aw and bls in tomato and al ₁ in pepper enhanced germination abilities under stress conditions regardless of the inherent seed properties that imparted rapid germination. This evaluation was conducted with four very different types of stress: 13 ^°C, 33 ^°C,120 mM NaCl and 15% PEG-6000 water solutions. The four genes exercised no effect on root and hypocotyl elongation under the same stress conditions and their effect on plantlets growth varied depending on the genotype and the treatment. The usefulness of genes ah, aw, blsand al ₁ in breeding tomato and pepper cultivars tolerant to adverse climatic conditions at germination when used as a morphological marker, is discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effects of high oleic acid soybean on seed yield,protein and oil contents,and seed germination revealed by near‐isogeneic lines

Typical soybean oil is composed of palmitic, stearic, oleic, linoleic and linolenic acids. High oleic acid content in soybean seed is a key compositional trait that improves oxidative stability and increases oil functionality and shelf life. Using a marker‐assisted selection method, near‐isogenic lines (NILs) of G00‐3213 for the high oleic trait were developed and yield tested. These NILs have various combinations of FAD2‐1A and FAD2‐1B alleles that were derived from the same backcrossing populations. The results indicated that G00‐3213 NILs with both homozygous mutant FAD2‐1A and FAD2‐1B alleles produced an average of 788 g/kg oleic acid content. The results also demonstrated that possessing these mutant alleles did not cause a yield reduction. Furthermore, seed germination tests across 12 temperatures (12.8–32.0°C) showed that modified seed composition for oleic acid in general did not have a major impact on seed germination. However, there was a possible reduction in seed germination vigour when high oleic seeds are planted in cold soil. The mutant FAD2‐1A and FAD2‐1B alleles did not hinder either seed or plant development.     

小麦抗白粉病近等基因系遗传背景的分子标记检测

利用AFLP分子标记技术,对近年来培育的几套近等基因系的遗传背景进行了检测,发现所检测到的遗传多样性主要集中于供体亲本之间,而近等基因系内部已达到很高的遗传一致性;包含Pm4b的近等基因系、包含Pm2/Pm6的近等基因系与轮回亲本遗传上比较接近,其内部选系之间也达到很高的一致性,是理想的近等基因系;发现Pm21中簇毛     

Fine mapping of a major quantitative trait locus, <Emphasis Type="Italic">qFLL6.2</Emphasis>, controlling flag leaf length and yield traits in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Fine mapping of a quantitative trait locus, qFLL6.2, controlling flag leaf length (FLL) and yield traits in rice was conducted using four sets of near isogenic lines (NILs) that were developed from a common residual heterozygote at F₇ generation of the indica rice cross Zhenshan 97/Milyang 46. Each of the NIL sets consisted of 40 lines that are S₁ progenies of ten maternal homozygotes, ten paternal homozygotes, and 20 heterozygotes differing in a portion of the 1.19-Mb interval RM3414–RM6917 on the short arm of rice chromosome 6. Analysis of phenotypic differences among the three genotypic groups in each NIL set delimited qFLL6.2 to a 62.1-kb region flanked by simple sequence repeat marker RM3414 and sequence-tagged site marker Si2944. This QTL explained 52.73% of the phenotypic variance, and the Zhenshan 97 allele increased FLL by 2.40 cm. Based on data collected from homozygous lines of three of the NIL sets, qFLL6.2 was shown to have major effects on all the three yield traits analyzed, including the number of spikelets per panicle, the number of filled grains per panicle, and grain weight per panicle. A comparison of the different groups revealed that the effect of qFLL6.2 was highly consistent across different genetic backgrounds and environments, providing a good candidate for map-based cloning and investigating the source–sink relationship in rice.     

Identification of near-isogenic lines: an innovative approach,validated for root and shoot morphological characters in a mapping population of rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Near-isogenic lines (NILs) constitute valuable tools in genetic investigations and plant breeding programs. Conventional methods for developing these are time consuming and tedious. An innovative method for identifying NILs is proposed and validated. The method involves computation of simple correlation coefficients of all possible pairs of genotypes within a mapping population using molecular marker data, and phenotypic characterization of those pairs with very high positive correlation. The pairs having both genomic and phenotypic similarity except for a single trait are considered as NILs. This strategy was tested with a doubled haploid mapping population involving CT9993 and IR62266. This population was saturated with 315 markers and comprised 154 lines. The pairs showing very high correlation coefficients (0.70–0.97) and differing for less than 10% of the markers were considered as Genotypically Closely Related Pairs (GCRPs). Graphical genotyping was employed to visualize the genome of the closely related lines. A total of 39 such pairs were subjected to rigorous evaluation for root and shoot morphological traits in two contrasting moisture regimes. Four GCRPs under well-watered condition and ten GCRPs under low moisture stress condition are statistically significant for a single phenotypic trait and are considered as NILs for their respective traits and would be the valuable materials for genetic studies. Mapped QTLs and candidate genes were employed to explain the probable cause of phenotypic difference in NILs.     

Tagging the juvenile locus in soybean [Glycine max (L.) Merr.] with molecular markers

Soybean cultivars carrying the `long juvenile trait' show a delayed flowering response under short day conditions. The incorporation of this character into genotypes of agronomic interest may allow a broader range of sowing dates and latitudes for a single cultivar adaptation. The objective of this work was to identify molecular markers linked to the juvenile locus in soybean. Experiments were carried out using two pairs of near isogenic lines(NILs) differing in the presence of the long juvenile trait, and RAPD markers. Four hundred primers were first screened to find polymorphism associated with the trait. Additional differences between NILs were sought by digesting the genomic DNA with five restriction enzymes. Polymorphic fragments detected between NILs were tested for linkage to the juvenile locus in the corresponding F₂ segregating populations. Marker bc357-HaeIII was linked (χ²L = 46.316) to the juvenile locus with an estimated recombination frequency of 0.13 ± 0.03in one of the genetic backgrounds studied. The fragment was cloned, sequenced and converted into a SCAR marker. Moreover,bc357-HaeIII was used as RFLP probe. Both, SCAR and RFLP generated markers linked to the juvenile locus in the two genetic backgrounds analysed. Results presented in this work can be utilised for both, the localisation of the gene associated with the character and for tagging the juvenile trait in soybean breeding programs. This revised version was published online in August 2006 with corrections to the Cover Date.     

以性状和分子标记为基础的水稻近等基因系的分离

以珍汕97/明恢63的一个含234个重组自交系的F6：7群体为材料, 通过以性状和分子标记为基础的方法在该群体中分离了每穗实粒数和千粒重这两个性状的近等基因系及对这两个性状有效应的QTL标记位点和两两互作位点的近等基因系。 在重组自交系RIL65和RIL197家系内分别分离了每穗实粒数和千粒重的近等基因系。 在重组自交系RIL54     

Development of near-isogenic lines for a major QTL on 3BL conferring Fusarium crown rot resistance in hexaploid wheat

By essentially fixing the genetic background, near-isogenic lines (NILs) are ideal for studies of the function of specific loci. We report in this paper the development of NILs for a major QTL located on the long arm of chromosome 3B conferring Fusarium crown rot (FCR) resistance in hexaploid wheat. These NILs were generated based on the method of the heterogeneous inbred family analysis. 13 heterozygous lines were initially selected from three segregating populations using a single SSR marker linked with the major FCR QTL. The two isolines for each of the putative NILs obtained showed no obvious morphological differences, but differences among the NIL pairs were large. Significant differences in FCR resistance between the isolines were detected for nine of the 13 putative NIL pairs. The presence of the FCR allele from the resistant parent reduced FCR severity by 29.3–63.9% with an average of 45.2% across these NILs. These NILs will be invaluable in further characterising this major FCR locus, in studying the mechanism of FCR resistance and in investigating possible interactions between FCR resistance and other traits of agronomic importance.     

Monogenic control of resistance in the tomato to the tobacco flea beetle: Probable repellance by foliage volatiles

Summary In comparisons made under typical summer conditions in the field at Davis, California, the foliage of the anthocyanin-deficient mutant af proved to be much more susceptible to attack by Epitrix hirtipennis (Melsheimer) than that of the isogenic normal line, normal cultivars, or any other tested mutant. Since a relatively uniform level of damage was observed in leaves of various ages that contacted the soil, the interaction is probably of a preference rather than antibiotic nature. A comparison with nine other anthocyaninless mutants proved that anthocyanin deficiency is not responsible for susceptibility. The severe reduction of glandular hairs and consequent lack of foliage aroma—hitherto unsuspected pleiotropic effects of af—probably account for the high susceptibility of this mutant. The evolutionary significance of the distinct foliage aromas characteristic of each tomato species is discussed.     

干旱条件下冬小麦近等基因系水分利用效率及其与气冠温差的关系

鉴定比较供体亲本京411和轮回亲本晋麦47及其34个近等基因系材料之间产量和水分利用效率(WUE),同时测定不同生育期的气冠温差(CTD),分析WUE在这些材料之间的变异范围,筛选WUE与轮回亲本显著差异的材料用于QTL定位,同时探索干旱条件下CTD与产量和WUE的关系及其随生育期进程变化的趋势。利用防雨棚和渗漏池开展模拟干旱试验。结果表明,34个近等基因系及其父母本WUE为1.30~1.92 kg/m~3,其中9个品系WUE显著低于轮回亲本晋麦47,表明WUE为多基因控制的数量性状,而且存在明显的加性效应。CTD与产量和WUE均呈极显著正相关关系。不同的是,随生育期进程推进,CTD与产量的相关性增强,在灌浆期最高,R2达到0.684 9,而与WUE的相关性减弱,R2在拔节-孕穗期最高,达到0.769 8。研究初步表明,CTD可以作为干旱条件下产量和WUE的鉴定指标。     

旗叶蜡质含量不同小麦近等基因系的抗旱性

于2013-2014和2014-2015年度,以多蜡质和少蜡质的4个小麦近等基因系为材料,采用田间旱棚方式控制土壤水分,研究了蜡质含量与小麦抗旱性的关系。结果表明,干旱处理后,多蜡质小麦品系旗叶的蜡质含量平均为15.15 mg g?1,较少蜡质小麦品系(8.43 mg g?1)高79.8%;多蜡质小麦品系旗叶的水势较高,干旱处理后下降幅度明显小于少蜡质小麦品系,水分散失率也显著低于少蜡质品系(P< 0.05);多蜡质小麦品系旗叶的光合速率平均下降7.5%,而少蜡质小麦品系下降9.8%;多蜡质小麦品系旗叶PSII最大光化学效率(Fv/Fm)平均下降幅度为3.4%,少蜡质小麦品系下降幅度达到5.8%;多蜡质小麦品系的籽粒产量高于少蜡质品系,平均高3.7%;多蜡质小麦品系的抗旱指数和干旱敏感指数均显著低于少蜡质小麦品系(P< 0.05)。以上结果表明,蜡质能够提高小麦的抗旱性,旗叶蜡质含量可以作为抗旱小麦品种的选择指标。     

The effects of cis-trans ABA on embryo germination and seed dormancy in wheat

Pre-harvest sprouting of wheat grain can cause economic losses especially in cultivars with low levels of seed dormancy. The aim of this study was to determine genotype differences in embryo sensitivity to germination in response to exogenous (+/–) cis-trans ABA treatments at different concentrations. Six white and four red seed-colored bread wheat genotypes that differed in dormancy were grown in a field near Swift Current, Saskatchewan in 2000 as a randomized complete block design with four replicates. The seed samples from this experiment were germinated in a controlled environment at 20 °C without light. The exogenous ABA treatments were 0 μM – whole seed (control), 0 μM-embryos, 25 μM – embryos and 50 μM – embryos. The ABA experiment was a factorial design with four randomized complete blocks with four ABA treatments in all combinations with the ten genotypes. A weighted (by day) germination index (WGI) was calculated for each genotype in each ABA treatment. Genotypes differed in response to ABA. The genotypes, ABA concentration and genotype by ABA concentration interaction effects were significant (p ≤ 0.05). Excised embryos showed significantly decreased dormancy in most of the experimental genotypes. The addition of exogenous ABA enhanced embryo dormancy of most genotypes. This revised version was published online in August 2006 with corrections to the Cover Date.     

Identification and validation of a major QTL for salt tolerance in soybean

To identify quantitative trait loci (QTLs) conditioning salt tolerance in soybean (Glycine max (L.) Merr.), two recombinant inbred line (RIL) populations derived from crosses of FT-Abyara × C01 and Jin dou No. 6 × 0197 were used in this study. The FT-Abyara × C01 population consisted of 96 F₇ RILs, and the Jin dou No. 6 × 0197 population included 81 F₆ RILs. The salt tolerant parents FT-Abyara and Jin dou No. 6 were originally from Brazil and China, respectively. The QTL analysis identified a major salt-tolerant QTL in molecular linkage group N, which accounted for 44.0 and 47.1% of the total variation for salt tolerance, in the two populations. In the FT-Abyara × C01 population, three RILs were found to be heterozygous around the detected QTL region. By selfing the three residual heterozygous lines, three sets of near isogenic lines (NILs) for salt tolerance were developed. An evaluation of salt tolerance of the NILs revealed that all the lines with FT-Abyara chromosome segment at the QTL region showed significantly higher salt tolerance than the lines without the FT-Abyara chromosome segment. Results of the NILs validated the salt tolerance QTL detected in the RIL populations.     

Inheritance and linkage relationships of isoenzymes in two interspecific cherry progenies

Two interspecific cherry progenies, Prunus avium ‘Napoleon’ × P. incisa E621 and ‘Napoleon’ × P. nipponica F1292, were analysed with polyacrylamide gel electrophoresis for 19 enzyme systems: alanine aminopeptidase (AAP), aldolase (ALD), alkaline phosphatase (AKP), arginine aminopeptidase (ARA), catechol oxidase (CO), diaphorase (DIA), endopeptidase (ENP), esterase (EST), formate dehydrogenase (FDH), fructose-bisphosphatase (FBP), β-galactosidase (GAL), glucose-6-phosphate dehydrogenase (G6PDH), β-glucosidase (GLU), glutamate dehydrogenase (GDH), glyceraldehyde-3-phosphate dehydrogenase (G3PDH), hexokinase (HEX), peroxidase (PRX), phosphorylase (PHO) and triose-phosphate isomerase (TPI). Activity for GAL was identical with GLU, and CO with PRX. In addition, activity for AKP was identical with some regions detected previously as acid phosphatase; and most of the PRX activity was identical with regions detected previously as superoxide dismutase. In all, 16 new segregating loci were identified, Ara-1, Dia-2, Est-1, Est-2, -6, -7 and -9, Glu-1 to -4, Hex-1, Pho-1 and -2, and Prx-8 and -9, together with 10 polymorphic putative loci. Analysis of cosegregations of the segregating loci with each other, and with loci established previously, resulted in 19 more loci being added to the cherry linkage map. Fifteen of these were new, and four had been described previously, but were hitherto unlinked. The additional linkages are: Ara-1– Dia-2– Mdh-2–Est-2; Glu-3/Prx-8–Glu-1/-2/-4–Prx-1/-9; Pgd-2–Pho-1/-2; Idh-2–Est-7–Est-6; (Amy-2)–Est-1–(Adh-4/-6); and (Acp-1/-2/-3)–Hex-1–(Gpi-2). (The bracketed loci had been mapped already). Several cherry linkages resemble linkages reported in apple. Analysis of 14 cultivars of P. avium for the same enzyme systems revealed polymorphism for just four of the 15 loci, and for an additional putative locus that was monomorphic in the interspecific material. This lack of isoenzyme polymorphism among cherry cultivars reduces the utility of these markers for linkage analysis and mapping in progenies of P. avium. This revised version was published online in July 2006 with corrections to the Cover Date.     

Quantitative trait loci controlling rice seed germination under salt stress

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, F_2:9), 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.     

Characterization and identification of cold tolerant near-isogenic lines in rice

To exploit the genetic mechanism of cold tolerance in rice, cold tolerant near-isogenic lines (NILs) were developed by backcrossing Kunmingxiaobaigu (KMXBG), reported to be the most cold-tolerant variety at the booting stage, as donor, with the cold sensitive Japanese commercial japonica variety, Towada. Comparisons of cold tolerance-related traits between five BC₆F₅ NILs and recurrent parent Towada under cold treatment and normal temperatures at the booting stage showed that the differences between the NILs and Towada were significant only for spikelet fertility-related traits. Analyses of cold tolerance in the NILs at the budding (germination), seedling and booting stages indicated both correlated effects and differences. Lines 1913-4 and 1916-1 showed strong and stable tolerance at all three stages. Whole genome marker screening showed that the proportion of genetic background recovery was more than 98%. Seventeen markers from KMXBG were introgressed in two or more NILs, and cold tolerance genes were possibly present in these marker regions. The NILs should be excellent materials for both rice improvement and map-based cloning of cold tolerance QTLs.     

大豆[Glycine max（L.）]成熟期近等基因系导入片段分析

选择243个多态性SSR标记, 分析轮回亲本Harosoy及23个携带大豆4个不同成熟期基因的近等基因系(near isogenic line, NIL), 共检测出导入片段266个, 平均每个NIL有导入片段11.6个。其中由携带E1基因的NIL检测出导入片段150个, 主要集中在第6号染色体;由携带E2、e3和E5基因的NIL各检测出导入片段55个、49个和73个, 分别集中在第20号、第12号和第20号染色体, 根据NIL的SSR分析结果聚类,具有相同熟期基因的NILs趋向聚在一起。通过对导入片段进行分析, 推测E1基因与第6号染色体的satt643~sat_312区间及第11号染色体的sat_095位点相关, E2和E5基因与第20号染色体的satt587~satt496区间相关, e3与第12号染色体的satt317~satt181区间相关。结果表明, 利用近等基因系不仅验证了已知E1基因所在的染色体区间, 发现了一个新的标记位点与E1相关, 还鉴定出与E2、e3和E5基因相关的标记, 明确了轮回亲本中成熟期基因所在导入片段大小及其位置, 为成熟期基因的精细定位和克隆提供了信息。     

Genetic analysis of low-temperature tolerance during germination in tomato, Lycopersicon esculentum Mill.

The genetic basis of low-temperature tolerance during germination of tomato seed was investigated using two approaches. First, a cold-tolerant (PI 120256) and a cold-sensitive tomato cultivar (UCT5) and their reciprocal F₂, F₃ and BC₁ progeny (total of 10 generations) were evaluated for germination at a low (11 ± 0.5°C) and a high (control) temperature 20 ±0.5° C) Weighted least-square regression analysis indicated that in the low-temperature treatment most of the variation resulted from additive genetic effects, and dominance and epistatic interactions were nonsignificant. Partitioning of the total genetic variance into those attributable to the effects of embryo, endosperm, testa and the cytoplasm indicated that additive effects of endosperm and embryo could individually account for 80% and 77% of the total variance, respectively. In the control treatment, greater than 60% of the variation could be explained by individual additive effects of endosperm or embryo and ? 27% of the variation could be explained by embryo dominance effects. Across generations, there was a positive correlation (r = 0.78, P < 0.01) between germination in the control and low-temperature treatments and there were no significant genotype × temperature interactions. The results indicate the presence of similar or identical genes with predominantly additive effects on germination under both low and high temperatures. In the second approach, the effectiveness of directional phenotypic selection to improve tomato cold tolerance during germination was evaluated by selecting (in an F₂ population of the same cross) the fastest germinating seeds under low temperature and comparing the germination of the selected F₃ progeny with germination of an unselected F₃ population. The results indicated that selection was highly effective and significantly improved germination performance of the progeny; a realized heritability of 0.74 was obtained for low-temperature tolerance during germination. It is concluded that in these tomato lines germination under low temperature is genetically controlled, with additivity being the major genetic component, and thus the trait can be improved by phenotypic selection.     

Effect of the gene for double pod in chickpea on yield, yield components and stability of yield

Five pairs of near isogenic lines (NILs) for the gene for single vs. double pod were used to study the effect of this character on yield and its components (seeds per plant, yield per plant and seed weight). The NILs were sown in 2 years at five locations in ihe first year and four locations in the second. Combined analysis of variance was applied to t he data and no significant differences between isolines were found, but there were significant genotype– location interaction effects for yield and seeds per plant. For both characters the double–podded lines were more stable than the single–podded lines. Although there were significant differences between the five genotypes lor yield per planl and seed weight, the differentes between single– and double–podded lines were almost nil. The results indicate that the double–pod gene has a positive effect on the stability of yield and is not linked to any other gene responsible Tor seed size in chickpea