Use of soil moisture data for refined GreenSeeker sensor based nitrogen recommendations in winter wheat (Triticum aestivum L.)

Previous studies have shown the importance of soil moisture (SM) in estimating crop yield potential (YP). The sensor based nitrogen (N) rate calculator (SBNRC) developed by Oklahoma State University utilizes the Normalized Difference Vegetation Index (NDVI) and the in-season estimated yield (INSEY) as the estimate of biomass to assess YP and to generate N recommendations based on estimated crop need. The objective was to investigate whether including the SM parameter into SBNRC could help to increase the accuracy of YP prediction and improve N rate recommendations. Two experimental sites (Lahoma and Perkins) in Oklahoma were established in 2006/07 and 2007/08. Wheat spectral reflectance was measured using a GreenSeeker? 505 hand-held optical sensor (N-Tech Industries, Ukiah, CA). Soil–water content measured with matric potential 229-L sensors (Campbell Scientific, Logan, UT) was used to determine volumetric water content and fractional water index. The relationships between NDVI, INSEY and SM indices at planting and sensing at 5, 25, 60 and 75-cm depths versus grain yield (GY) were evaluated. Wheat GY, NDVI at Feekes 5 and soil WC at planting and as sensed at three depths were also analyzed for eight consecutive growing seasons (1999–2006) for Lahoma. Incorporation of SM into NDVI and INSEY calculations resulted in equally good prediction of wheat GY for all site-years. This indicates that NDVI alone was able to account for the lack of SM information and thus lower crop YP. Soil moisture data, especially at the time of sensing at the 5-cm depth could assist in refining winter wheat YP prediction.     

QTL for grain yield and yield parameters in winter wheat(Triticum aestivum L.)

Field trials with a set of 108 doubled haploid lines(DHs) derived from a cross between the Chinese winter wheat cvs.CA9613 and H1488 were run at Beijing(China).Phenotypic data were recorded for major agronomic yield traits,i.e.grain weight per ear,grain number per ear and thousand grain weight(Tgw) in two field trials at Beijing.Based on the phenotypic data and a genetic map comprising 168 SSR markers,an analysis of quantitative trait loci(QTL) was carried out for yield and yield parameters using the composite interval mapping(CIM) approach.A total of 14 QTL were detected for these traits across two environments.Four of these QTL located on chromosomes 1A and 2B,respectively,exhibited pleiotropic effects.Loci showing pleiotropic effects will be very useful for understanding the homeologous relationships of QTL and designing an appropriate marker-assisted selection programme by multi-trait selection in order to accumulate("pyramide") favorable alleles at different loci.     

小麦戊聚糖研究进展

戊聚糖是小麦籽粒中非淀粉多糖的主要成分.戊聚糖在小麦籽粒中的含量较低,但它对小麦的营养品质和加工品质都有重要的影响.本文综述了近年来国内外关于小麦戊聚糖的最新研究进展,包括小麦品种间戊聚糖含量的变异、戊聚糖的影响因素和遗传特性、戊聚糖与农艺性状关系及戊聚糖对小麦品质的影响等,旨在为中国小麦品质改良提供依据.     

基于小麦品种‘洛夫林10’的VIGS体系研究

为将病毒介导的基因沉默(Virus induced gene silencing,VIGS)技术应用于小麦-叶锈菌互作体系及小麦基因功能研究,本试验在优化适宜BSMV繁殖并引起发病的环境条件基础上,将病毒载体转染小麦品种‘洛夫林10’(简称L10)叶片并接种叶锈菌生理小种,发现接种病毒对叶锈菌侵染反应型没有影响,通过构建TaCAMTA4与TaATG8的BSMV-VIGS载体,将体外转录病毒转染小麦,以感染BSMV:PDS的L10作指示,在指示叶片变白后,经半定量RT-PCR检测,发现目的基因的表达量明显降低,表明用VIGS技术能够成功沉默L10中的目的基因,这一结果为进一步研究小麦与叶锈菌互作过程中小麦基因的功能及分子机制奠定了基础。     

小麦雌性育性QTL的高效定位策略

为了高效地定位小麦雌性育性QTL,以选择表型及连锁不平衡结合策略筛选候选标记.对选取的SSR 标记在实验群体中以隐性极端不育亚群体估算其重组频率( c 值) ,确定染色体2AS、2DS 上可能存在QTL.再对候选染色体上18个标记分别计算c 值,并用育成品种与小麦雌性不育系XND 126组成的品种(系)群体计算标记与可能位点间的连锁不平衡值( LD 值) .结合c 值和LD 值提供的位点信息构建部分连锁群,通过实验群体F２ 的连锁分析定位了小麦雌性育性位点taf1.结果发现与taf1 位点连锁较紧密的标记,其c 值较小而LD 值较大.分析认为结合连锁分析和关联分析优势,同时选择c 值较小而LD 值较大的多态性标记有利于快速确定与位点紧密连锁的标记,从而达到高效定位QTL 的目的,并有助于揭示小麦雌性育性的遗传机制.     

高产冬小麦深耘断根提高粒重的生理分析

为研究探讨高产条件下深耘断根提高冬小麦粒重的机理,于1997-1999年采用2个品种,设置4个处理,对精播栽培技术体系下高产小麦的多项生理指标进行了测定.结果表明:深耘断根可使小麦旗叶光合速率峰期后移、延缓叶绿素含量下降速率,延缓功能叶衰老,使根系发育良好、活力提高.深耘断根可加大籽粒蔗糖合成酶(SS)活性、提高穗部ATP含量.深耘断根能提高旗叶磷酸蔗糖合成酶(SPS)活性,强化光合产物转化,保持了小麦长时期、高强度灌浆.结合前人研究,定性构建了深耘断根提高冬小麦拉重的机理模型.     

土壤水分对越冬期间冬小麦叶绿素荧光参数的影响

采用两个抗寒性不同的冬小麦品种为试验材料,设置了土壤绝对含水量15%±2%、30%±2%、45%±2%和对照(35%～40%,CK)正常管理等4个水分处理,6个取样时期,对越冬期冬小麦叶片的叶绿素荧光参数,Fo(初始荧光)、Fm(最大荧光)、Fv/Fm(最大量子产量)、Yield(实际量子产量)进行了测定.结果表明.品...     

小麦产量构成因素的基因效应和杂种优势分析

为提高对小麦产量构成因素的选择效率,以7个半冬性小麦品种及按7×7双列杂交设计的21个F1杂交组合在2个地点的试验资料,研究了小麦2个产量构成因素—每穗粒数和千粒质量的基因效应和杂种优势。结果表明,每穗粒数和千粒质量的遗传符合加性-显性模型,基因显性效应的作用远大于其加性效应,显性程度为超显性。增效基因为显性,减效基因为隐性。每穗粒数和千粒质量在2个试点的平均狭义遗传力分别为54.00%和63.17%。每穗粒数和千粒质量表现正向的平均杂种优势和超亲优势,变异幅度较大,并在基因型、地点及基因型与地点互作间存在极显著差异。     

Breeding for drought tolerance in wheat (Triticum aestivum L.): constraints and future prospects

This review article is based on different aspects of wheat breeding for drought tolerance. Drought is regarded as one of the most serious threats to agriculture in Pakistan. Therefore, breeding for drought tolerance must be given top priority. Here, we try to study various options available to wheat breeders exploring the underlying mechanisms of drought tolerance. The progress made in conventional and non-conventional (molecular) based approaches with potential findings and constraints are reviewed in this article. Equipped with such information, it will be possible for breeders to further explore the mysteries of drought tolerance and to select genotypes with an improved yield under water-deficit conditions.     

小麦粒长和粒宽的QTL定位分析

【目的】粒长、粒宽是小麦种子重要的形态性状,该性状对籽粒的外观商品品质、产量及磨粉品质均至关重要,研究不同环境条件下小麦粒长、粒宽的单个标记和复合区间作图的QTL定位,对小麦粒长、粒宽的分子标记辅助选择具有重要参考作用。【方法】应用一个由115个系组成的W7984/Opata 85重组自交系(RIL)群体,建立了由394个DNA分子标记组成的遗传连锁图,在2种不同环境条件下对小麦粒长、粒宽进行了单个标记的回归分析和复合区间作图的QTL定位。【结果】在单个标记的回归分析中检测到5个粒长的QTLs、3个粒宽的QTLs;复合区间作图分析结果表明,控制粒长的QTLs分别位于5BL和7DS上,在5BL上的贡献率为20.20%~20.81%,LOD值为4.50~4.55;在7DS上的贡献率为13.54%~13.91%,LOD值为2.94~3.20。控制粒宽的QTL位于2B上,贡献率为13.71%~19.30%,LOD值为2.98~4.18。【结论】位于5B和7D上的控制粒长的QTL和位于2B上的控制粒宽的QTL在2种条件下均能检测到。     

Genome-wide association analysis for stripe rust resistance in spring wheat(Triticum aestivum L.) germplasm

Stripe rust is a continuous threat to wheat crop all over the world. It causes considerable yield losses in wheat crop every year. Continuous deployment of adult plant resistance(APR) genes in newly developing wheat cultivars is the most judicious strategy to combat this disease. Herein, we dissected the genetics underpinning stripe rust resistance in Pakistani wheat germplasm. An association panel of 94 spring wheat genotypes was phenotyped for two years to score the infestation of stripe rust on each accession and was scanned with 203 polymorphic SSRs. Based on D' measure, linkage disequilibrium(LD) exhibited between loci distant up to 45 c M. Marker-trait associations(MTAs) were determined using mixed linear model(MLM). Total 31 quantitative trait loci(QTLs) were observed on all 21 wheat chromosomes. Twelve QTLs were newly discovered as well as 19 QTLs and 35 previously reported Yr genes were validated in Pakistani wheat germplasm. The major QTLs were QYr.uaf.2 AL and QYr.uaf.3 BS(PVE, 11.9%). Dissection of genes from the newly observed QTLs can provide new APR genes to improve genetic resources for APR resistance in wheat crop.     

水稻和小麦根际的联合固氮作用

本文阐述了水稻和小麦根际的联合固氮作用的测定方法和联合固氮量。通常认为,     

Mapping QTLs for stomatal density and size under drought stress in wheat(Triticum aestivum L.)

Stomatal density and size affect plant water use efficiency, photosynthsis rate and yield. The objective of this study was to gain insights into the variation and genetic basis of stomatal density and size during grain filling under drought stress(DS) and well-watered(WW) conditions. The doubled haploid population derived from a cross of wheat cultivars Hanxuan 10(H10), a female parent, and Lumai 14(L14), a male parent, was used for phenotyping at the heading, flowering, and mid- and late grain filling stages along with established amplified fragment length polymorphism(AFLP) and simple sequence repeat(SSR) markers. The stomatal density of doubled haploid(DH) lines was gradually increased, while the stomatal lengths and widths were gradually decreased during grain filling stage. Twenty additive QTLs and 19 pairs of epistatic QTLs for the 3 traits were identified under DS. The other 20 QTLs and 25 pairs epistatic QTLs were obtained under WW. Most QTLs made more than 10% contributions to the total phenotypic variations at one growth stage under DS or WW. Furthermore, QTLs for stomatal density near Xwmc74 and Xgwm291 located on chromosome 5A were tightly linked to previously reported QTLs regulating total number of spikelets per spike, number of sterile spikelets per spike and proportion of fertile spikelets per spike. Qsw-2D-1 was detected across stages, and was in the same marker region as a major QTL for plant height, QPH.cgb-2D.1. These indicate that these QTLs on chromosomes 5A and 2D are involved in regulating these agronomic traits and are valuable for molecular breeding.     

土壤高砷污染对冬小麦和油菜生长影响的比较研究

采用盆栽试验研究了土壤高浓度砷污染对冬小麦和油菜生长、生物量、产量的影响及磷、砷在此2种作物各个部位的累积规律。结果表明,200 mg·kg-1土壤砷污染显著抑制了冬小麦的生长,收获时冬小麦株高较对照降低17%;冬小麦地上部分、根系的生物量和产量较对照分别降低了52.2%,60.6%和46.8%。但土壤砷污染对油菜株高、生物量影响均不显著,产量较对照降低了15.4%。砷在冬小麦、油菜各部位的含量为根系>茎叶>颖壳(角果皮)>种子。相同砷污染条件下,小麦根系砷浓度(74.86 mg·kg-1)显著高于油菜根系砷浓度(57.76 mg·kg-1),但地上部分砷含量差异不大,冬小麦籽粒中砷的含量高于油菜籽粒,但均未超过0.7 mg·kg-1。土壤砷污染对冬小麦、油菜根系、茎叶中磷含量影响不大,但显著降低了颖壳(角果皮)中磷的含量。油菜较冬小麦对砷有更高的耐性,砷污染土壤中种植越冬作物时,更适合种植油菜。     

Conditional and unconditional QTLs mapping of gluten strength in common wheat(Triticum aestivum L.)

Dissecting the genetic relationships among gluten-related traits is important for high quality wheat breeding. Quantitative trait loci(QTLs) analysis for gluten strength,as measured by sedimentation volume(SV) and gluten index(GI),was performed using the QTLNetwork 2.0 software. Recombinant inbred lines(RILs) derived from the winter wheat varieties Shannong 01-35×Gaocheng 9411 were used for the study. A total of seven additive QTLs for gluten strength were identified using an unconditional analysis. QGi1 D-13 and QSv1 D-14 were detected through unconditional and conditional QTLs mapping,which explained 9.15–45.08% of the phenotypic variation. QTLs only identified under conditional QTL mapping were located in three marker intervals:WPT-3743–GLU-D1(1 D),WPT-7001–WMC258(1 B),and WPT-8682–WPT-5562(1 B). Six pairs of epistatic QTLs distributed nine chromosomes were identified. Of these,two main effect QTLs(QGi1 D-13 and QSv1 D-14) and 12 pairs of epistatic QTLs were involved in interactions with the environment. The results indicated that chromosomes 1 B and 1 D are important for the improvement of gluten strength in common wheat. The combination of conditional and unconditional QTLs mapping could be useful for a better understanding of the interdependence of different traits at the QTL molecular level.     

小麦赤霉酸不敏感基因Gai3的遗传研究

以小麦Ｒｈｔ３的两个株高等基因系及其ＢＣ２３Ｆ２分离群体为材料,分析了与Ｒｈｔ３矮秆基因连锁的赤霉酸不敏感基因Ｇａｉ３的遗传规律及其与Ｒｈｔ３的遗传关系。结果表明：赤霉酸不敏感性由单个显性基因控制,Ｆ２分离比率为３∶１（不敏感∶敏感）,非常符合χ２测验。Ｇａｉ３基因与Ｒｈｔ３基因连锁紧密,交换值为０．０６０±０．０１２和０．０５５±０．０１３。     

小麦矮秆突变体矮秆基因的遗传分析

目前在小麦中虽然已经命名了20余个矮秆基因,但小麦矮秆基因资源应用单一化的现状仍然存在,因此对小麦新矮源的筛选与研究显得十分必要。本研究以1个小麦矮秆突变体‘矮128’为材料,通过赤霉酸处理、遗传分析、基因等位性测验和DNA分子标记等手段分析了该矮秆突变体矮秆基因的性质及可能来源。结果表明:‘矮128’属赤霉酸不敏感型矮秆突变体,其矮秆性状受1对隐性基因控制,该基因与Rht8、Rht9、Rht13、RhtB1b(Rht1)、RhtD1b(Rht2)、RhtD1c(Rht10)和Rht16等矮秆基因不是等位基因,也不同于Rht4、Rht5、Rht8、Rht9、Rht12、Rht13等6个已知矮秆基因。尽管如此,‘矮128’中的矮秆基因是否为新的矮秆基因仍然需进一步的遗传分析加以明确。     

Spectral vegetation indices selected for quantifying Russian wheat aphid (Diuraphis noxia) feeding damage in wheat (Triticum aestivum L.)

The effects of insect infestation in agricultural crops are of major economic interest because of increased cost of pest control and reduced final yield. The Russian wheat aphid (RWA: Diuraphis noxia) feeding damage (RWAFD), referred to as ??hot spots??, can be traced, indentified, and isolated from uninfested areas for site specific RWA control using remote sensing techniques. Our objectives were to (1) examine the use of spectral reflectance characteristics and changes in selected spectral vegetation indices to discern infested and uninfested wheat (Triticum aestivum L.) by RWA and (2) quantify the relationship between spectral vegetation indices and RWAFD. The RWA infestations were investigated in irrigated, dryland, and greenhouse growing wheat and spectral reflectance was measured using a field radiometer with nine discrete spectral channels. Paired t test comparisons of percent reflectance made for RWA-infested and uninfested wheat yielded significant differences in the visible and near infrared parts of the spectrum. Values of selected indices were significantly reduced due to RWAFD compared to uninfested wheat. Simple linear regression analyses showed that there were robust relationships between RWAFD and spectral vegetation indices with coefficients of determination (r ²) ranging from 0.62 to 0.90 for irrigated wheat, from 0.50 to 0.87 for dryland wheat, and from 0.84 to 0.87 for the greenhouse experiment. These results indicate that remotely sensed data have high potential to identify and separate ??hot spots?? from uninfested areas for site specific RWA control.     

Genetic analysis and QTL mapping of a novel reduced height gene in common wheat(Triticum aestivum L.)

Low stature in wheat is closely associated with lodging resistance, and this impacts harvest index and grain yield. The discovery of novel dwarfing or semi-dwarfing genes can have great significance for dwarf wheat breeding. In this study, we identified an EMS-induced dwarf wheat mutant JE0124 from the elite cultivar Jing411. JE0124 possesses increased stem strength and a 33% reduction in plant height compared with wild type. Gibberellic acid(GA) treatment analysis suggested that JE0124 was GA-sensitive. Analysis of the frequency distribution of plant height in four F2 populations derived from crosses between JE0124 and the relatively taller varieties Nongda 5181 and WT indicated that the dwarfism phenotype was quantitatively inherited. We used two F2 populations and 312 individuals from the reciprocal cross of Nongda 5181 and JE0124 to map the quantitative trait locus(QTL) for reduced height to a 0.85-cM interval on chromosome 2 DL. The mapping was done by using a combination of 660 K SNP array-based bulked segregant analysis(BSA) and genetic linkage analysis, with logarithm of odds(LOD) scores of 5.34 and 5.78, respectively. Additionally, this QTL accounted for 8.27–8.52% of the variation in the phenotype. The dwarf mutant JE0124 and the newly discovered dwarfing gene on chromosome 2 DL in this study will enrich genetic resources for dwarf wheat breeding.