玉米自交系抗旱相关性状的主成分分析与模糊聚类

采用主成分分析(Principal Components Analysis,PCA)和模糊聚类(Fuzzy Clustering,FC)分析,对51个玉米自交系在正常灌溉和干旱胁迫条件下的主要农艺形状及部分生理指标进行分析并对其抗旱性进行综合评价。主成分分析结果表明,4个综合主成分(2012TMC:丰产性因子-雄穗发育性因子,光合调控性因子,生长发育性因子,繁茂性因子;2012HT:丰产性因子-生长发育性因子,光合调控因子,繁茂性因子,雄穗发育因子)可代表两个地区(2012TMC和2012HT)玉米自交系抗旱性91.05%的原始数据信息量。利用抗旱性度量值进行模糊聚类,可将51个玉米自交系的抗旱性划分为4类,即耐旱、中度耐旱、中度干旱敏感和干旱敏感。其中H201、H21、英64、吉842、早49、吉8415、东46和沈137抗旱性强且稳定性好。利用主成分分析,结合模糊聚类的方法进行玉米自交系的抗旱性综合评价,不仅可以避免单一指标的片面性,而且可以较好地揭示玉米自交系抗旱相关性状与其抗旱性的关系。     

棉花抗旱品种筛选鉴定及抗旱性综合评价方法

从甘肃敦煌、新疆的棉花栽培品种和国内外引进材料中选出76个遗传来源不同的棉花品种(系)作为参试材料,在年降雨量不足40 mm的甘肃省敦煌市设置了干旱胁迫和正常灌水两个处理,筛选出与棉花抗旱性密切相关的10个农艺性状和产量指标,采用综合抗旱系数(CDC)、综合抗旱指数(CDI)、综合隶属函数值(CDM)、抗旱性综合评价值(D)等四种综合评价方法对76份种质材料进行抗旱性评价。结果显示,四种综合评价方法两两之间的Pearson相关系数都在0.88以上,相关性均达到了极显著水平;再利用四种抗旱评价体系得分值对76个受试棉花品种(系)进行K-means划分聚类,最终将76个品种分为高抗(Ⅰ类,5个品种)、抗(Ⅱ类,9个品种)、中等(Ⅲ类,17个品种)、敏感(Ⅳ类,31个品种)、高敏(Ⅴ类,14个品种)5个抗旱等级。为进一步方便育种家简单准确地评价选育材料的抗旱性,利用筛选出的10个农艺性状指标的抗旱系数作为自变量,四种抗旱性综合评价体系得分值为因变量,采用逐步回归的方式建立了棉花抗旱性预测模型回归方程。     

苦荞种质资源性状评价及优异资源筛选

对180份苦荞种质资源的12个主要农艺性状进行遗传多样性分析、主成分分析以及聚类分析。结果表明,180份苦荞种质间株粒重和株粒数的差异较大,变异系数均高于60%。根据苦荞种质性状间的遗传差异,对12个主要农艺性状进行主成分分析,得到的4个主成分因子累计贡献率达82.729%,第1主成分反映籽粒形状,第2主成分反映产量,第3、4主成分分别反映籽粒大小和株型。聚类分析把180份苦荞种质划分为3个类群,类群Ⅰ可以作为选育矮秆、特异粒形品种的优良亲本;类群Ⅱ可作为选育高秆品种的优良亲本;类群Ⅲ可作为选育高产、大粒品种的优良亲本。从矮秆、高产和大粒3个方面,筛选出矮秆材料灵石苦荞、安泽苦荞、苦荞60、苦荞62,高产材料二各苦荞、武乡苦荞、苦荞27、老鸭咀苦荞、苦荞34、苦荞35和大粒材料泸西苦荞、额角瓦齿、姚安苦荞1、苦荞61,共14份优异苦荞种质资源。     

蒙古莸种质资源表型性状多样性分析

为了明确荒漠灌木蒙古莸野生种质资源的表型多样性以及与环境因子的关系,对40个天然种群的蒙古莸,进行5个生长性状和11个叶片性状的多样性、聚类、主成分分析。结果显示：蒙古莸的16个表型性状变异系数范围在0.102-0.507之间,株高变异系数最大,叶形状系数的变异系数最小;遗传多样性指数范围在1.625-2.086之间;Pearson相关系数表明表型性状之间存在显著的相关关系,表型性状与种源地环境因子间也有较强的相关性。按株型和叶片性状聚类将蒙古莸种群分为4个类群,其中第Ⅰ类种群株型大,叶片也较大;第Ⅱ类种群株型大,但叶片相对较小;第Ⅲ类种群株型小,叶片也小;第Ⅳ类种群株型小,但叶片大;聚类种群表型性状表现出与种源地环境相适应的特征。文中结果表明蒙古莸种质资源表型变异丰富,多样性水平高,且表型与环境因子密切相关,为蒙古莸种质资源的保护和研究利用提供理论依据。     

山西高粱品种(系)的花后抗旱性评价

以22份山西历年审定(鉴定、登记)的高粱品种及预登记的高粱品种为参试材料,通过自然干旱(DS)和正常灌溉(NI)两种处理方式,采用大田自然鉴定法,调查农艺性状、品质性状和光合性状3类主要性状指标。结合隶属函数(U)和干旱敏感指数(S)的聚类分析法及热图法对材料进行分类,对抗旱指标进行综合评价。结果表明：在干旱胁迫下,高粱品种除了穗柄伸出长平均增长5.26 cm和单宁含量平均增加0.09%,其余性状指标均出现下降;除净光合速率外,其余性状指标之间均存在一定程度的相关性。利用以上两种方法,筛选出极抗品种3份(S9、S10和S7即晋杂108、晋杂22号和晋杂101),极弱品种1份(S17即晋杂4号)。根据干旱敏感指数计算,主成分分析为9个性状,主成分累计贡献率84.662%,产量和单穗粒重是决定第一主成分的主要性状,贡献率为17.999%。干旱胁迫对高粱品种(系)花后主要性状指标均有显著影响。不同高粱材料间抗旱性差异显著,应用两种抗旱性评价方法,可以较为准确地评价参试高粱品种(系)的抗旱性。产量、单穗粒重、株高和倒二叶叶宽可以作为评价高粱花后抗旱性的主要形态指标。     

玉米品种开花期抗旱性鉴定指标筛选

为了筛选有效的抗旱性指标,评价玉米品种的抗旱性,以已筛选出的抗旱性有差异的12个玉米品种为材料,采用抗旱池栽试验,设干旱胁迫和正常灌水2个处理,考察了与产量相关的形态和生理生化等33个性状,运用灰色关联分析和主成分分析方法,以抗旱隶属度、产量抗旱系数和抗旱指数为评价参数,结合模糊函数法,对各玉米品种的抗旱性进行综合评价.综合灰色关联和主成分分析结果表明,反映干旱条件下与抗旱性密切相关的有净光合速率(Pn)、实际量子产量(φPSⅡ)、叶绿素含量(Chl)、叶面积、干物质等5个指标,并结合抗旱隶属度进行综合评价,评价结果与经典的抗旱指数法评价结果一致.表明用筛选出的5个指标对玉米开花期抗旱性评价是可行的,提出的综合分析法是一种玉米抗旱性鉴定较为有效的科学方法.     

除草剂乙草胺胁迫下油菜品种的耐药生理研究

研究甘蓝型油菜在乙草胺胁迫下的耐药生理对非转基因耐乙草胺的油菜新种质选育有重要意义?本研究以纸床法测定乙草胺耐药品种‘Norin 41’和敏感品种‘Dong Hae 1’生长7 d的幼苗进行生物性状?还原型谷胱甘肽代谢?抗氧化分析以及品种表型性状之间的相关性分析和主成分分析?结果表明, 耐药品种生长?根抗倒伏性?乙草胺解毒能力和抗氧化能力均强于敏感品种, 耐药品种的氧化损伤低于敏感品种?直立苗率?根-茎比?鲜重?超氧化物歧化酶活性?谷胱甘肽S-转移酶活性和丙二醛含量是反映品种耐药性的主要因素?这些研究结果为耐乙草胺种质选育提供了有益参考?     

黑龙江糜子种质资源农艺性状遗传多样性

对黑龙江省149份糜子种质资源的11个农艺性状进行了评价鉴定。结果表明:该批糜子种质资源具有较为丰富的遗传多样性,6个数量性状的遗传多样性指数分别为千粒重(2.06)、主茎高(2.02)、主穗长(2.02)、生育期(1.94)、单株粒重(1.79)、主茎节数(1.37),5个质量性状的遗传多样性指数分别为粒色(1.87)、花序密度(0.64)、穗型(0.64)、花序色(0.51)、穗分枝长(0.46);相关分析结果表明,单株粒重与穗型和花序密度呈极显著正相关;主成分分析结果表明,前4个主成分累计贡献率达到72.49%,第1主成分主要与穗型有关,第2主成分主要与生育期有关,第3主成分主要与籽粒性状有关,第4主成分主要与产量有关;聚类分析在遗传距离为10.0时将149份糜子种质划分为4类;筛选出20份具有早熟、矮秆、大穗的糜子资源。     

54个小麦品种(系)抗赤霉病评价与农艺性状调查

为获得抗赤霉病且农艺性状较好的小麦种质资源, 加快小麦抗赤霉病育种进程, 采用人工接种鉴定和田间试验的方法, 于2019年-2021年, 对54个小麦品种(系)进行了赤霉病抗性鉴定与农艺性状调查。结果表明, 供试小麦品种(系)存在赤霉病抗性差异, 筛选出‘华皖麦24’‘宛1204’和‘皖垦麦1708’等9个两年表现稳定的中抗品种(系), 占总数的16.67%; 农艺性状调查结果显示, 不同小麦品种(系)的农艺性状间存在显著性差异, 抗病组品种(系)的平均变异系数小于感病组品种(系)。其中, ‘宛1204’和‘徐麦17252’中抗赤霉病, 且综合农艺性状较好, 可以作为抗赤霉病育种的抗源。     

云南割手密及其血缘F1代材料抗旱相关性状的主成分分析

本研究对15个云南不同生态型割手密血缘F₁代创新种质材料及其亲系共28个材料,在自然生长与干旱胁迫条件下的生长发育状况密切相关的13个指标进行主成分与模糊聚类分析,综合评价参试材料的抗旱性。试验结果表明：(1) 叶绿素因子、地下干物质积累因子和地上干物质积累因子等前6个主成分因子方差累计贡献率达90.11%,可代表原始指标的大部分信息量;(2) 利用抗旱性度量值将参试材料聚为4大类6个亚类,聚入第Ⅰ类的共有4个创新种质材料,占参试材料的14.3%,尤其是云割F₁08-317、云割F₁08-319表现出较强的抗旱性;第Ⅱ、Ⅲ类材料分别占参试材料的42.9%、39.3%,都分为2个亚类,其中云割F₁08-392、云割F₁08-391、云割F₁08-511、云割F₁08-397、云割F₁08-617等5个创新种质材料,可在育种实践中优先利用;云割F₁08-541单独聚为第Ⅳ类,其抗旱性还有待进一步研究。     

Potential contribution of selected canopy traits to the tolerance of foliar disease by spring barley

A model of canopy photosynthesis and above-ground growth rate was used to investigate the potential impact of several canopy traits on tolerance of foliar disease by barley. Disease tolerance was defined as the reduction in predicted crop dry-matter growth rate per unit of visible disease symptoms. The traits were canopy area (leaf area index, LAI ), light extinction coefficient ( k ) and the ratio of virtual to visible lesion size ( β ). The effects of altering the area of the healthy flag leaf and its light-saturated rate of photosynthesis (P_max) in response to disease elsewhere on the plant were also investigated. The model was parameterized for spring barley and run with a solar radiation and temperature regime typical of north-east Scotland. Predicted reductions in growth rate per unit increase in disease were greatest at high disease severity and when disease was distributed relatively uniformly through the canopy. Tolerance was increased by increasing LAI to >3 and k to >0·3, but the beneficial effects depended on the severity and, to a lesser extent, the distribution of disease. Tolerance was reduced by increasing β . A sensitivity analysis performed at a single disease severity and distribution showed that tolerance was most sensitive to variations in β and compensatory adjustments in area and P_max of the flag leaf, and least sensitive to whole canopy LAI and k . Future research should quantify the genetic variation in these traits within barley germplasm to evaluate the scope for improving the disease tolerance of spring barley.     

A Compromised Mlo Pathway Affects the Response of Barley to the Necrotrophic Fungus Bipolaris sorokiniana (Teleomorph: Cochliobolus sativus) and Its Toxins

ABSTRACT In search of new durable disease resistance traits in barley to control leaf spot blotch disease caused by the necrotrophic fungus Bipolaris sorokiniana (teleomorph: Cochliobolus sativus), we developed macroscopic and microscopic scales to judge spot blotch disease development on barley. Infection of barley was associated with cell wall penetration and accumulation of hydrogen peroxide. The latter appeared to take place in cell wall swellings under fungal penetration attempts as well as during cell death provoked by the necrotrophic pathogen. Additionally, we tested the influence of a compromised Mlo pathway that confers broad resistance against powdery mildew fungus (Blumeria graminis f. sp. hordei). Powdery mildew-resistant genotypes with mutations at the Mlo locus (mlo genotypes) showed a higher sensitivity to infiltration of toxic culture filtrate of Bipolaris sorokiniana as compared with wild-type barley. Mutants defective in Ror, a gene required for mlo-specified powdery mildew resistance, were also more sensitive to Bipolaris sorokiniana toxins than wild-type barley but showed less symptoms than mlo5 parents. Fungal culture filtrates induced an H2O2 burst in all mutants, whereas wild-type (Mlo) barley was less sensitive. The results support the hypothesis that the barley Mlo gene product functions as a suppresser of cell death. Therefore, a compromised Mlo pathway is effective for control of biotrophic powdery mildew fungus but not for necrotrophic Bipolaris sorokiniana. We discuss the problem of finding resistance traits that are effective against both biotrophic and necrotrophic pathogens with emphasis on the role of the anti-oxidative system of plant cells.     

A weed suppressive index for spring barley (Hordeum vulgare) varieties

A screening programme for crop variety competitiveness would ideally be based on only a few, non-destructive measurements of key growth traits. In this study we measured the weed suppressive ability of 79 varieties of spring barley in two ways: (i) directly, by weed coverage assessments under weedy conditions at three Danish locations in 2002–2004 and (ii) indirectly, by non-destructive measurements of varietal growth traits under weed-free conditions in 17 other experiments in Denmark in 2001–2003. Based on just four varietal growth traits (reflectance, leaf area index, leaf angle and culm length), we successfully developed a method for indexing the weed suppressive ability of spring barley varieties. The suppressive index ranged from 12% in Lux and 55% in Modena in proportion to the 90% quantile coverage of all varieties. The index was validated against independent data from two locations in 2005 with 14 and 24 varieties and was found valuable for future use in regular screening programmes.     

Early vigour and allelopathy – two useful traits for enhanced barley and wheat competitiveness against weeds

The objectives of this study were to identify traits in spring barley (Hordeum vulgare) and spring wheat (Triticum aestivum) related to the competitive ability of the crop and to determine their importance. Weed biomass 1–2 weeks prior to ear emergence was used as a measure of genotypic differences in competitiveness against weeds. Crop trait measurements comprised early crop biomass, early shoot height, straw length, heading and maturity. Early crop biomass 1–2 weeks prior to ear emergence was used as an overall trait for the various characters related to early vigour. In addition to these morphological traits, the potential allelopathic activity of the tested cultivars was determined using an agar-based bioassay with Lolium perenne (ryegrass). In both barley and wheat, multiple regression analysis revealed that early crop biomass and potential allelopathic activity were the only parameters that significantly contributed to competitiveness. In barley, early crop biomass explained 24–57% of the observed genotypic variance across 4 years, allelopathic activity explained 7–58% and combined they explained 44–69% of the observed genotypic variance. In wheat, the corresponding figures were lower: 14–21% for early biomass, 0–21% for allelopathic activity and 27–37% when combined. Model predictions suggested that new cultivars with increased early vigour and allelopathic activity offer a potential to further reduce weed interference.     

大麦抗条纹病与SSR标记的关联分析

为了解不同来源大麦的遗传多样性,并筛选与抗条纹病性状相关联的SSR标记,采用三明治法通过人工接种大麦条纹病菌Pyrenophora graminea对180份大麦材料进行抗性鉴定,通过119对多态性SSR引物对180份大麦材料进行SSR标记分析,并用一般线性模型(general lineal model,GLM)和混合线性模型(mixed lineal model,MLM)进行大麦抗条纹病与SSR标记的关联分析。结果表明,人工接种大麦条纹病菌后共鉴定出10份免疫、9份高抗、25份抗病、70份感病和66份高感大麦材料;119对多态性SSR引物从180份大麦材料中共检测出559个等位变异位点,平均为4.70个,变幅为2～14个,基因多样性和多态性信息含量变幅分别为0.05～0.88和0.05～0.86;群体结构分析表明供试大麦材料可分为2个亚群。基于GLM和MLM分别检测到14个和10个与大麦条纹病抗性相关联的SSR标记,对表型变异的解释率变幅分别为4.46%～9.76%和3.25%～7.87%,其中Scssr08238和BMS64标记均与大麦条纹病抗性呈极显著相关,二者在GLM中解释率分别为9.76%和8.00%,在MLM中解释率分别为7.87%和5.61%。本研究所鉴定的大麦抗性种质可作为抗源用于抗病育种,与抗性相关联的SSR标记可用于大麦抗条纹病的分子标记辅助选择育种。     

Increased crop diversity reduces the functional space available for weeds

There is a drive to improve the sustainability of agricultural systems including the biodiversity component. Cultivar mixtures offer yield benefits from the same land area, but the mechanisms behind this overyielding have not been completely worked out. One potential mechanism is improved competition with weeds. We use an experimental approach of varying barley (Hordeum vulgare L.) genotypic and phenotypic diversity to test the hypothesis that increases in diversity have an impact on weed growth strategies and community assembly, or if responses are driven by barley performance. There was no effect of increasing barley mixture diversity on weed traits, either in terms of species means or the community-weighted mean. However, Functional Richness of the weed community decreased with increasing barley mixture diversity mainly as a result of reduced specific leaf area Functional Richness. This pattern was driven by a reduction in species richness of the weed community rather than by reduced variation within species. Whilst barley phenotype had different impacts on weed traits, there were no specific mixtures of phenotypes or genotypes that had consistent effects on community assembly or weed species responses. The competitive exclusion of weed species could have agronomic and environmental benefits, through better targeting or less frequent use of herbicides. Growing crop mixtures is one of many strategies available to improve agricultural sustainability and resilience, and one that has clear benefits.     

Resistance in Australian barley (Hordeum vulgare) germplasm to the exotic pathogen Puccinia striiformis f. sp. hordei,causal agent of stripe rust

Eighty‐eight Australian and 10 international barley cultivars were assessed for resistance to the barley stripe (yellow) rust pathogen, Puccinia striiformis f. sp. hordei (Psh). All cultivars were tested for seedling resistance to two UK‐derived isolates of Psh (11.01 and 83.39) that were shown to differ in virulence based on responses on 16 differential barley genotypes. The 98 barley cultivars differed substantially in stripe rust response; 45% were susceptible to Psh 11.01, 53% to Psh 83.39 and 44% to both isolates. The observed diverse infection types (ITs) suggest the presence of both known and uncharacterized resistance. However, further multipathotype tests are required for accurate gene postulation. The Yerong × Franklin (Y×F) doubled haploid (DH) population was phenotypically assessed as seedlings using both Psh isolates. Yerong and Franklin were immune and highly resistant, respectively, to both isolates used in this study. Marker‐trait and QTL mapping identified a major effect on the long arm of chromosome 7H contributed by Franklin in response to all isolates. The resistance of Yerong was mapped to 113·96 and 169·38 cM on chromosome 5HL in response to Psh 11.01 and 83.39, respectively. The Psh resistance sources identified in this study can be used for further genetic analysis and introgression for varietal improvement.     

Barley traits associated with resistance to fusarium head blight and deoxynivalenol accumulation

ABSTRACT Fusarium head blight (FHB) or scab is a destructive disease of barley in many countries. A better understanding of the interrelationships between plant traits and FHB resistance should help in the development of effective and efficient breeding strategies for FHB-resistant cultivars. Recent mapping studies indicate that many of the quantitative trait loci (QTL) for FHB resistance coincide with the QTL for plant height, heading date, and spike characteristics. Therefore, a study was conducted to investigate the relationship of morphological and physiological traits to FHB infection and deoxynivalenol (DON) accumulation in a barley doubled-haploid (DH) population derived from a Léger x CI9831 cross. Approximately 190 DH lines were grown at Ottawa (Ontario) for 2 years, Charlottetown (Prince Edward Island) for 1 year, and Hangzhou (Zhejiang) for 2 years. The field plots were inoculated with Fusarium graminearum at each location. FHB incidence was positively correlated with DON content. Resistance to FHB was associated with two-row spike, purple lemma, long glume awn, tall stature, and resistance to lodging, but it was not associated with long rachilla hairs, rough lemma awn, or heading date. Two-row spike was associated with tall stature and resistance to lodging. These associations as well as its spike characteristics helped reduce FHB infection and DON accumulation in two-row lines compared with six-row lines. The association between long glume awn and FHB resistance could be due to genetic linkages. Therefore, trait associations should be taken into consideration when breeding for FHB resistance and interpreting data from FHB experiments.     

进境澳大利亚大麦上葡萄茎枯病菌的检疫鉴定

自进境澳大利亚大麦样品上,采用常规平板分离法获得1株疑似葡萄茎枯病菌菌株74919。通过形态学特征观察、β-tubulin和actin序列比对分析以及致病性测定,对该菌株进行了种类鉴定。结果表明:菌株74919在PDA培养基上生长良好,可产生大量分生孢子器和厚垣孢子;基于β-tubulin和actin序列构建的系统发育树中,菌株74919和其他葡萄茎枯病菌相关序列划分在同一分支;菌株74919接种大麦叶片,在接种部位引起叶斑症状。根据上述实验结果,将菌株74919鉴定为葡萄茎枯病菌(Didymella glomerata),这是我国口岸首次从进境澳大利亚大麦中截获葡萄茎枯病菌。     

How can research on pathogen population biology suggest disease management strategies? The example of barley scald (Rhynchosporium commune)

Barley scald fungus, Rhynchosporium commune, belongs to a host‐specialized species complex infecting grasses. Coalescent analyses of several genes indicate that R. commune originated c. 2500 years ago, after the domestication of barley. Phylogeographical analyses identified a diversity hotspot in Scandinavia, indicating an origin in northern Europe. After its emergence, R. commune became distributed globally on infected seeds, eventually invading the Fertile Crescent and infecting wild barley progenitors. Analyses of gene flow identified historical routes of migration out of Scandinavia and indicate a high degree of modern gene flow among South Africa, Australia and New Zealand. About 76% of global species diversity is found within barley fields, with all field populations showing a genetic structure consistent with sexual recombination. High levels of regional gene flow suggest wind‐dispersed ascospores and movement of infected seed. Quantitative traits, including pathogen aggressiveness, thermal sensitivity and fungicide resistance, showed high heritability and high levels of diversity within nine globally representative populations. Field experiments provided evidence for a fitness cost associated with complex virulence and a trade‐off between pathogenic and saprophytic fitness. All findings indicate that global R. commune populations have significant potential to evolve rapidly in response to environmental changes, including deployment of resistant cultivars, fungicide applications and global warming. Specific recommendations to improve management of barley scald include: (i) focus resistance breeding efforts in northern Europe, which offers the best location to screen germplasm and may provide useful sources of scald resistance; (ii) improve seed treatment, certification and quarantine programmes to limit long distance pathogen movement; (iii) manage barley stubble to decrease pathogen population size, limit production of sexual inoculum and reduce the pathogen's evolutionary potential.