GWAS for resistance against black point caused by Bipolaris sorokiniana in wheat

Black point is a severe wheat grain disease caused by complex pathogens, of which Bipolaris sorokiniana is dominant. Analysis of effective resistance genes/quantitative trait loci (QTL) is an essential prerequisite for breeding by marker-assisted selection (MAS). In this study, we aimed to identify the loci resistant to black point caused by B. sorokiniana in 10 wheat genotypes by performing a genome-wide association study with an incomplete diallel cross population. Twenty-three major marker-trait associations (MTAs) resistance to B. sorokiniana black point were identified, which could explain more than 11% of the phenotypic variations. They were located on 1B, 1D, 2B (2), 2D, 3A (2), 3B (2), 3D, 4A, 5A (2), 5B (2), 6B (3), 6D, 7A (2), and 7D (2), respectively. The average number of major MTAs in the 10 resistant lines was 20.2, whereas that in the susceptible lines was 9.8. All the major MTAs in the parents were detected in the F₁ hybrids. Three PCR markers were developed for detecting two MTAs using two recombinant inbred line populations. These PCR markers linked to black point resistance and accessions with a larger number of resistance alleles can be used to improve wheat resistance by QTLs pyramiding via MAS.     

啤酒大麦新品种新啤4号的选育及栽培要点

1选育经过 新啤4号是新疆农科院奇台麦类试验站1994年采用日本引进品种红日啤麦作母本,耶费欧作父本,经系统选择,2000年成为稳定品系,2001年进行产量鉴定,2002至2003年在本站进行品系比较试验,两年平均6 190.5/hm 2,比对照法瓦维特增产9.7%,2004至2007年在不同生态区进行生产示范,2006至2007年参加自治区啤酒大麦区域试验,2007年同时参加了自治区生产试验.     

不同地区红茶特异性香气成分比较研究

采用固相微萃取（HS-SPME）结合气质联用（GC-MS）技术,对比分析了中国及印度、斯里兰卡等不同地区7类红茶的香气组成及特异性香气成分.检测出149种挥发性香气物质,分析表明中国红茶香气化合物以醇类、醛类为主导,印度及斯里兰卡红茶中酯类、烯烃类相对含量明显较高.主成分分析能将不同地区红茶明显分为三类：1.安徽祁红、福建金骏眉表现出以香叶醇为主体的玫瑰花香;2.云南滇红、广东英德红表现出以芳樟醇为主的花果香、甜香;3.印度、斯里兰卡红茶体现以水杨酸甲酯为主的似薄荷冬青香气.品种特性、环境气候及加工工艺对香气特征有影响,不同地区红茶香气特异性风格明显.     

Identification of a phytoplasma associated with pomegranate little leaf disease in Iran

During 2012–2014 surveys for the presence of phytoplasma diseases in Fars province (Iran), pomegranate little leaf symptoms were observed in several orchards in Khafr and Neyriz areas. Samples collected from symptomatic plants positively reacted in nested PCR assays using P1/P7 followed by R16F2n/R16R2 primer pairs producing the expected 1,250 bp DNA fragments. Real and virtual RFLP analysis showed that the sequences of phytoplasma strains from Khafr and Neyriz (KPLL and NPLL strains, respectively) were identical to each other and belong to 16SrII phytoplasma group, subgroup D. Phylogenetic analysis of the R16F2n⁄R16R2 DNA region confirmed that KPLL and NPLL phytoplasmas were enclosed in the same clade as other 16SrII-D subgroup phytoplasmas. This is the first reported occurrence of a 16SrII phytoplasma infecting pomegranate trees.     

Measurement of genetic and environmental variation in barley (Hordeum vulgare) grain hardness

In this study, we assessed a broad range of barley breeding lines and commercial varieties by three hardness methods (two particle size methods and one crush resistance method (SKCS—Single-Kernel Characterization System), grown at multiple sites to see if there was variation in barley hardness and if that variation was genetic or environmentally controlled. We also developed near-infrared reflectance (NIR) calibrations for these three hardness methods to ascertain if NIR technology was suitable for rapid screening of breeding lines or specific populations. In addition, we used this data to identify genetic regions that may be associated with hardness. There were significant (p<0.05) genetic effects for the three hardness methods. There were also environmental effects, possibly linked to the effect of protein on hardness, i.e. increasing protein resulted in harder grain. Heritability values were calculated at >85% for all methods. The NIR calibrations, with R² values of >90%, had Standard Error of Prediction values of 0.90, 72 and 4.0, respectively, for the three hardness methods. These equations were used to predict hardness values of a mapping population which resulted in genetic markers being identified on all chromosomes but chromosomes 2H, 3H, 5H, 6H and 7H had markers with significant LOD scores. The two regions on 5H were on the distal end of both the long and short arms. The region that showed significant LOD score was on the long arm. However, the region on the short arm associated with the hardness (hordoindoline) genes did not have significant LOD scores. The results indicate that barley hardness is influenced by both genotype and environment and that the trait is heritable, which would allow breeders to develop very hard or soft varieties if required. In addition, NIR was shown to be a reliable tool for screening for hardness. While the data set used in this study has a relatively low variation in hardness, the tools developed could be applied to breeding populations that have large variation in barley grain hardness.     

QTLs for malting flavour component associated with pre-harvest sprouting susceptibility in barley (Hordeum vulgare L.)

Lipoxygenase (LOX) is a key factor affecting quality of beer in terms of foam stability and flavour. Low LOX content is a desirable trait for malting quality. A doubled haploid (DH) population was made from a cross of Australian malting barley Stirling and Canadian malting barley Harrington and mapped with 513 molecular markers. The 120 DH lines with their parents were planted in field trials and the harvested grains were micro-malted for analysis of LOX content in two consecutive years. LOX content was controlled by both genetic effects and environment conditions. Three QTLs were consistently detected. One QTL flanked by the markers E6216 and SCssr03907 at the telomere region of chromosome 5HL contributed 39% of genetic variation in LOX content. The second QTL close to the centromere region of chromosome 5H accounted for 17% of genetic variation. A minor QTL on chromosome 2H explained 6% of genetic variation but was significant in both years. The Australian variety Stirling contributed to higher LOX content for the three QTLs. The two QTLs mapped at chromosome 5H for LOX content coincided with the QTLs for seed dormancy/pre-harvest sprouting from the same population. The pre-harvest sprouting susceptible alleles were associated with low LOX content, which indicated that the low LOX QTL from the Canadian malting barleys are only useful in the barley growing areas where the pre-harvest sprouting risk is low. New genetic sources for low LOX should be exploited in different germplasm with different mechanisms.     

The identification of a barley haze active protein that influences beer haze stability: The genetic basis of a barley malt haze active protein

In bright beers, the formation of haze is a serious quality problem, which places limitations on the storage life of the product. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) immunoblot analysis using an antiserum that was raised against a silica eluate (SE) protein fraction (obtained from silica gel, used for the colloidal stabilisation of beer), detected a range of protein bands in barley, malt, beer and haze. A polymorphism was observed in which some barley varieties contained a molecular weight (MW) 12,000 band (SE +ve) while in other varieties this band was absent (SE −ve). A survey of 219 Australian and international barley varieties, including a comprehensive selection of current and past malting varieties, identified 181 varieties as SE +ve, and 38 varieties as SE −ve. Previous pilot brewing trials demonstrated that SE −ve varieties are desirable as the beer brewed from the malt of these varieties formed less haze after accelerated ageing than beers brewed using SE +ve malt varieties. The genetic basis for the absence of the SE protein was conferred by a recessive allele at a single locus. Interval mapping analysis showed that the MW 12,000 band mapped to the short arm of chromosome 3H.     

Identification of quantitative trait loci for β-glucan concentration in barley grain

The amount of (1 → 3),(1 → 4)-β-d glucan (β-glucan) accumulated in cell walls of barley (Hordeum vulgare L.) kernel is an important determinant for grain end-use. Grain β-glucan concentration is affected by environmental and genetic factors and usually varies from 3 to 6%. In this study, we have analyzed the β-glucan trait in a doubled-haploid (DH) population of 170 lines grown in three separate field trials. Most of the DH lines showed β-glucan values that ranged from that of the low β-glucan parent (cultivar CDC Bold; 3.3%) to that of the high β-glucan parent (breeding line TR251; 5.4%). Eighty-eight lines of the DH population were genotyped using simple sequence repeat (SSR), amplified fragment length polymorphism (AFLP) and diversity array technology (DArT) markers, which were subsequently integrated into a barley genetic map spanning 1059 cM. Interval mapping and multiple-QTL-mapping (MQM) of quantitative trait loci (QTL) from the three trials indicated seven genomic regions associated with low grain β-glucan concentration. For all putative QTLs, the low β-glucan concentration was contributed by alleles from CDC Bold except for two loci on chromosomes 5H that were derived from TR251. A major QTL located to the centromere region of chromosome 7H was identified by both mapping methods for all three trials. The 7H QTL explained up to 39% of the β-glucan concentration and genetic markers associated with the locus may be used to aid selection of high and low β-glucan barley lines.     

通过关联分析鉴定与花生脂肪酸含量相关分子标记

油酸、亚油酸和棕榈酸是花生油脂中最主要的3种脂肪酸,其含量是影响花生油脂品质的重要因素。提高油酸含量并降低亚油酸和棕榈酸含量是花生品质性状改良的重要方向之一。本研究利用292份中国花生种质资源材料及583个SSR标记基因型数据对四个环境下不同脂肪酸含量进行关联分析,分别检测到与油酸、亚油酸和棕榈酸含量稳定关联标记14,14和9个,其中8个标记同时与上述3种脂肪酸含量稳定关联,分布在A02、A03、A08和A09染色体上。AHGS2050-226bp和AHGS3647-253bp是两个新关联标记的优异等位位点,在花生微微核心种质中证实,AHGS2050-226bp可提高油酸（9.99%～11.26%）并降低亚油酸（8.04%～9.31%）和棕榈酸含量（1.86%～1.97%）,AHGS3647-253bp可提高油酸（9.79%～10.44%）并降低亚油酸（8.09%～8.62%）和棕榈酸含量（1.81%～1.95%）。本研究鉴定的多环境稳定关联标记AHGS2050和AHGS3647具有辅助选择高油酸且低亚油酸和低棕榈酸品种的潜在应用价值。     

Identification of QTLs and candidate genes for physiological traits associated with drought tolerance in cotton

Background:Cotton is mainly grown for its natural fiber and edible oil.The fiber obtained from cotton is the indispensable raw material for the textile industries.The ever changing climatic condition,threatens cotton production due to a lack of sufficient water for its cultivation.Effects of drought stress are estimated to affect more than 50%of the cotton growing regions.To elucidate the drought tolerance phenomenon in cotton,a backcross population was developed from G.tomentosum,a drought tolerant donor parent and G.hirsutum which is highly susceptible to drought stress.Results:A genetic map of 10888 SNP markers was developed from 200 BC_2F_2 populations.The map spanned 4191.3 centi-Morgan(c M),with an average distance of 0.1047 c M,covering 51%and 49%of At and Dt sub genomes,respectively.Thirty stable Quantitative trait loci(QTLs)were detected,in which more than a half were detected in the At subgenome.Eighty-nine candidate genes were mined within the QTL regions for three traits:cell membrane stability(CMS),saturated leaf weight(SLW)and chlorophyll content.The genes had varied physiochemical properties.A majority of the genes were interrupted by introns,and only 15 genes were intronless,accounting for 17%of the mined genes.The genes were found to be involved molecular function(MF),cellular component(CC)and biological process(BP),which are the main gene ontological(GO)functions.A number of mi RNAs were detected,such as mi R164,which is associated with NAC and MYB genes,with a profound role in enhancing drought tolerance in plants.Through RT-q PCR analysis,5 genes were found to be the key genes involved in enhancing drought tolerance in cotton.Wild cotton harbors a number of favorable alleles,which can be exploited to aid in improving the narrow genetic base of the elite cotton cultivars.The detection of 30 stable QTLs and 89 candidate genes found to be contributed by the donor parent,G.tomentosum,showed the significant genes harbored by the wild progenitors which can be exploited in developing more robust cotton genotypes with diverse tolerance levels to various environmental stresses.Conclusion:This was the first study involving genome wide association mapping for drought tolerance traits in semi wild cotton genotypes.It offers an opportunity for future exploration of these genes in developing highly tolerant cotton cultivars to boost cotton production.     

Heritabilities,gains from selection and genetic correlations for grain yield of barley grown in two contrasting environments

Heritabilities and variance component estimates were obtained from a set of 15 barley lines and cultivars grown for three consecutive years in two contrasting environments in the high plateaux of Eastern Algeria. Genotype × environment interactions, particularly related to seasonal effects, seriously limited selection for increased barley grain yield. Their effect was to reduce the genetic variance component, heritability estimates and genetic correlation coefficients.The results indicated that selection in a high-yielding location does not identify genotypes suitable for low-yielding environments, which are more representative of the production conditions of a low-input agriculture. Selection in low-yielding environments appears more efficient.     

Occurrence,development, and losses associated with silver scurf and black dot on Colorado potatoes

Silver scurf, caused byHelminthosporium solani, and black dot, caused byColletotrichum atramentarium, are pathogens of tuber periderm whose presence in Colorado was only recently reported. A field survey conducted in September 1977 revealed thatC. atramentarium was more prevalent (21.8% tuber infection) and had a wider distribution thanH. solani (5.4% tuber infection). A greater incidence of both pathogens was observed on thin skinned tubers of chipping cultivars (49.0% infection) than on thicker skinned tubers of table stock cultivars (9.1% infection). Conidial development ofH. solani is tretic, pleurogenous, and requires 17–21 hours per conidium. Conidial septations appear while conidial elongate, and require 3–5 hours per septum. Light microscopy revealed that at least 11 conidia per conidiophore are produced in culture in 54 hours at 20–25 C (68–77 F) and humidity >90%. Scanning electron microscopy showed that fructifications ofH. solani (conidiophores-conidia) arise from beneath infected tuber periderm. Histological studies indicate some peridermal loosening and sloughing. Heavy deposition of unidentified compounds was observed in infected periderm, and hyphae were restricted to periderm cells. Fresh weight loss of tubers naturally infected withC. atramentarium was significantly greater than fresh weight loss of nearly noninfected (< 1% surface area infected) control tubers. Periderm infected with eitherH. solani orC. atramentarium appeared similar, i.e. shriveled, suggesting infections from either pathogen may result in increased fresh weight loss through alteration of the periderm.     

QTL analysis across multiple environments reveals promising chromosome regions associated with yield-related traits in maize under drought conditions

Drought is one of the most critical abiotic stresses influencing maize yield. Improving maize cultivars with drought tolerance using marker-assisted selection r...     

Genomic regions associated with the degree of red coloration in pericarp of rice (Oryza sativa L.)

The degree of red coloration (DRC) in pericarp of rice depends on the content of flavonoid compounds which have beneficial health effects for humans. In this study, 182 backcross-recombinant inbred lines (BILs) derived from Koshihikari (white pericarp)/Kasalath (red pericarp)//Koshihikari were used to detect the genomic regions associated with DRC through the QTL mapping approach. As a result, a total of four genomic regions were found to associate with DRC on chromosomes 1, 7, 9 and 11, respectively. Interestingly, the two genomic regions having the largest effects corresponded to previously characterized Rc and Rd genes on chromosome 7 and 1, respectively. In addition, two novel genomic regions having minor effects on DRC and located on chromosomes 9 and 11, respectively, are reported here for the first time. These results and the identification of tightly linked molecular markers that flank the genomic regions provide an opportunity for marker-aided improvement of red coloration in pericarp of rice.     

Effect of carbon black nanoparticles on reflective behavior of printed cotton/nylon fabrics in visible/near infrared regions

Tuning the level of visible and near infrared (NIR) reflectance of textile surfaces is crucial for making them undetected in each environment. In this regard, samples of cotton/nylon fabrics were printed using a mixture of some special pigments and carbon black (CB) nanoparticles to produce brown, olive green and khaki shades which are present in concealment patterns of textiles employed in deserts. The effect of CB nanoparticles on Vis/NIR reflectance, air permeability, perspiration, light, wash fastnesses, and colorimetric values of each printed sample were evaluated. The presence of CB nanoparticles in printing formulations was found to cause significant decline in Near Infrared (NIR) reflectance of samples. The results showed that air permeability of samples printed containing CB nanoparticles are higher than samples printed with no CB particles. Absorbing phenomenon imposed by CB nanoparticles was fast against washing and perspiration, although printed samples indicated high to moderate light fastness. Furthermore, detectable change in visible appearance of the printed patterns was the main point of concern even at concentrations as low as 0.05 g/kg CB in printing formulation.     

甘蓝型油菜渝黄1号黄籽性状的AFLP和SSR标记

以甘蓝型黄籽杂交油菜渝黄1号为试验材料,用F2群体中的9株黑籽单株和12株黄籽单株的DNA分别构成黑籽集团和黄籽集团.通过BSA法筛选了96个AFLP引物组合和173对SSR引物,鉴定出与显性黄籽基因连锁的1个AFLP标记E35M52180和1个SSR标记P039230,标记与显性黄籽基因的交换率分别为4.9%和2.5%.此外还发现1个SSR标记P055240与深色种皮有关.     

Hull to caryopsis adhesion and grain skinning in malting barley: Identification of key growth stages in the adhesion process

Strong adhesion between the hull and the caryopsis is essential for barley to be of good malting quality. Poor hull adhesion, a condition known as grain skinning, is undesirable for malting and downstream processes. At present, the processes mediating hull adhesion during grain development are poorly understood. The barley cultivar Chariot was grown in greenhouse conditions and grain development was recorded at defined growth stages to examine the timing of hull adhesion. Initiation of adhesion was first observed when caryopsis fresh weight and volume were approaching their maximum at 19 days after anthesis, during early dough. Hull adhesion was complete by 27 days after anthesis, or soft dough. Sections of developing grains were observed using light and transmission electron microscopy to examine a lipid-rich cementing layer believed to be responsible for adhesion between the hull and the pericarp. Evidence for a lipid-rich cementing material was supported by the observation that neither pectinase nor cellulase effected hull loosening. Grain growth, the presence of globular material originating from the pericarp and an electron dense material in the cementing layer are discussed in relation to hull adhesion. Grain skinning could be caused by poor adherence of cuticular material or inadequate fusion between cuticles.     

Genetic variants of HvGlb1 in Tibetan annual wild barley and cultivated barley and their correlation with malt quality

Improvement of malt quality is the most important objective in malt barley breeding. The current experiments investigated the variation of malt quality characters among barley genotypes and the difference in genetic variants of HvGlb1, encoding β-glucanase isoenzyme I, between Tibetan annual wild barley and cultivated barley. The correlation between the gene variants and malt quality showed that there was a large difference in the four malt quality parameters, i.e. Kolbach index, diastatic power (DP), viscosity and malt extract, among the analyzed barley cultivars. Kolbach index was negatively and positively correlated with viscosity and malt extract, respectively, while malt extract was negatively correlated with viscosity. Malt β-glucan content was a major determinant of malt quality, and was significantly correlated with Kolbach index (−0.633), malt extract (−0.333) and viscosity (0.672). On the other hand, malt β-glucan content was mainly controlled by malt β-glucanase activity. The correlation analysis showed that the HvGlb1 gene was correlated with malt β-glucan content and three of four main malt quality parameters, except DP. In addition, we also found that the HvGlb1 of Tibetan barley had wider diversity in haplotype than that of the cultivated barley, supporting the hypothesis that Tibet is one of the original centers of cultivated barley.     

Identification of genetic factors influencing chip color in diploid potato (Solanum spp.)

A genetic map was constructed with a combination of isozymes, restriction fragment length polymorphisms (RFLPs) and randomly amplified polymorphic DNA (RAPDs) to apply quantitative trait loci (QTL) analysis to identify genetic factors that contribute to chip color in potato. The diploid population used was a cross between aSolanum tuberosum haploid andS. chacoense hybrid used as female parent and aS. phureja clone used as male. Chip color was determined visually on samples fried from tubers stored at 10C. On a scale of 1 (light color) to 10 (dark color), the population ranged from 2 to 8 while the parents average chip color was 3.5. Based upon one-way ANOVAs (P < 0.05), 13 genetic markers showed significant associations which represent a total of six QTLs. A multiple locus model based upon the markers that have the largest effect per QTL explained 43.5% of the phenotypic variation for chip color in the population and increased to 50.5% when one significant epistatic interaction was included in the model. All the significant marker associations were identifed in theS. tuberosum-S. chacoense hybrid. Through preliminary data, the results of this study suggest that additive effects contribute a significant portion of the genetic variation for chip color. The identification of these QTLs for chip color variation provides the means to apply marker-assisted selection to introgress these genes into the cultivated potato germplasm.