我国小麦农家品种和近缘种对白粉病的苗期抗性

由布氏白粉菌小麦专化型引起的白粉病是最重要的小麦叶部病害之一。抗性资源和抗性基因的发掘对控制该病害起了重要作用。小种专化抗性基因的抗性水平较高, 成为当前小麦生产上使用最为广泛的白粉病抗性基因。然而,这类抗性基因的广泛使用会导致菌系结构的改变, 并产生新的毒性小种。因此, 从大量小麦种质资源中鉴定新的、有效的白粉病抗性基因是一个长期的目标。为鉴定有效的白粉病抗源, 通过苗期接种国内流行白粉菌生理小种E09, 来评价258 份国内小麦农家品种和42 份小麦近缘种的抗性。结果表明, 有5份农家品种和20 份小麦近缘种对E09 表现免疫、近免疫或高抗。这25 份抗源被用来进一步接种另外5 个不同的国内生理小种E03、E05、E18、E20 和E23, 以推知它们所携带的未知抗性基因。通过与28 个已知白粉病抗性基因的抗谱进行比较发现, 这25 份小麦种质的抗性基因不同于Pm1a、Pm2、Pm3a、Pm3b、Pm3c、Pm3d、Pm3e、Pm3f、Pm4a、Pm4b、Pm4c、Pm5a、Pm6、Pm7、Pm8、Pm9、Pm17、Pm19、Pm24、Pm28 和Pm33等21 个已知抗性基因, 但与Pm1c、Pm1e、Pm12、Pm13、Pm16、Pm20 和Pm21 等7 个已知抗性基因仍需要进一步的区分。鉴于这25 份抗源与上述7 个已知抗性基因载体的来源不尽相同, 因此, 这些抗源很可能携带有未知的抗白粉病新基因, 但还需用更多的白粉菌生理小种来鉴定。本研究旨在从小麦农家品种及其近缘种中发掘新的有效抗源, 从而为抗白粉病新基因的发掘和有效利用奠定基础。     

Identification of powdery mildew and leaf rust resistance genes in common wheat (Triticum aestivum L.). Wheat varieties from the Caucasus, Central and Inner Asia

225 wheat varieties from Kazakhstan, Mongolia and Russia were analysed for their resistance to powdery mildew and leaf rust diseases. A set of 11 different Blumeria graminis f. sp. tritici isolates was used to test for powdery mildew resistance and a set of 10 different Puccinia triticina isolates for leaf rust. 115 cultivars/lines were susceptible to powdery mildew and 32 cultivars/lines showed an intermediate resistance response. 21 cultivars/lines revealed the response pattern of individual resistance genes Pm1, Pm2, Pm3, pm5, Pm6, Pm8, Pm9, Pm17 and Pm22, respectively, therefrom three line showed a combination of two resistance genes and two varieties a combination of three genes. 50 cultivars/lines showed resistance to some specific isolates but an assignment to known resistance genes or gene combinations was not possible, whereas seven lines were completely resistant to all used isolates. The leaf rust test showed that 83 cultivars/lines were susceptible and 11 lines revealed intermediate resistance response. 62 cultivars/lines could be assumed to possess major resistance genes Lr1, Lr3, Lr10, Lr23 and Lr26, respectively, therefrom seven cultivars possessed a combination of two resistance genes. Lr3 was the most widespread resistance gene, occurring in 42 cultivars/lines. 13 lines were completely resistant to all used isolates, however, the response patterns of 56 cultivars/lines did not match to any known gene or gene combination. In 13 varieties the T1BL·1RS wheat-rye translocation could be identified, in five cultivars resistance gene Pm8 was suppressed.     

小麦抗白粉病分子育种研究进展

小麦白粉病是小麦生产的主要病害之一,应用抗病品种是防治该病的十分经济、有效的措施。近年来分子标记技术的发展为小麦抗白粉病基因的研究提供了极大的方便。目前为止,小麦基因组中已定名抗白粉病主效基因有38个,其中有41个基因位点的57个抗白粉病基因被标记和作图。本文详细叙述了小麦抗白粉病基因的来源、抗病基因利用及其分子标记研究现状,介绍了国内外分子育种研究最新进展,旨在为我国抗小麦白粉病分子育种提供参考。     

山西省小麦条锈病流行趋势预测模型研究

本研究分析了山西省小麦条锈病流行的影响因素和预测依据;对1981～2003年流行情况资料,采用回归分析法,建立预测模型:Y=-0.2766 0.0249X1 0.0104X2 0.0132X3,经回归检验,历史符合率高达87.5%。通径分析进一步证明,4月中旬～5月下旬的降雨量对条锈病流行具有最显著影响。     

Detection of adult-plant resistance to Puccinia triticina in a collection of wild Triticum species

Three hundred and fifty three Triticum accessions, several also classified as Aegilops and comprising 13 diploid, tetraploid or hexaploid species, were screened for seedling and adult-plant resistance to Puccinia triticina Eriks. using a mixture of pathotypes UVPrt2, 3, 9 and 13. Seedlings were spray-inoculated with a suspension of freshly collected urediospores in distilled water containing Tween 20^® seven days after planting. Infection types (ITs) were scored 10 days post-inoculation (d.p.i.). Fully expanded flag leaves were inoculated and ITs and leaf rust severity were scored 16 d.p.i. One hundred and eighty two of the accessions were resistant to moderately resistant in the adult stage, whereas 126 were resistant or moderately resistant as seedlings to the pathotype mixture. Hypersensitive adult-plant resistance was particularly apparent in lines of T. timopheevii, T. sharonense, T. longissimum, T. searsii and T. turgidum. In T. turgidum, which comprised 272 accessions, approximately 44% of the adult plants were resistant to moderately resistant compared to 28% of the seedlings. The expression of these adult-plant resistances varied between hypersensitive flecking of flag leaves, and small pustules commonly associated with chlorosis and/or necrosis of leaf tissue. Partial resistance, expressed by small pustules without any apparent chlorosis, was observed in species such as T. tauschii, T. turgidum ssp. durum and T. turgidum ssp. pyramidale.     

Chromosomal distribution and genetic expression of Lophopyrum elongatum (Host) A. Löve genes for adult plant resistance to stripe rust in wheat background

A set of wheat cv. Chinese Spring (CS)-Lophopyrum elongatum addition and substitution lines has been analyzed for its potential to offer new sources of stripe rust resistance for wheat. The adult plants of these lines, together with CS-L. elongatum amphiploid and CS, were inoculated by new physiological races CYR-30 and CYR-31 of stripe rust in China. The resistance investigation indicated that chromosome 7E1 of L. elongatum was responsible for the adult resistance in CS background. Moreover, the expression of the adults plant resistance derived from chromosome 7E1 in wheat background was dependent on the wheat genotype. In addition, the different rust resistance and glutenin composition were observed in 2 CS-L. elongatum amphiploids, indicating the genetic diversity existed in different origins of L. elongatum.     

不同品种混种对小麦产量及条锈病的影响

用"繁19"、"引11-12"、"川麦107"、"靖麦10号","青春55"、"46548-3"和"安96-8"7个不同小麦品种,组合成6个品种混种的群体,于2003～2004年、2004～2005年、2005～2006年在云南省曲靖市对其产量效应进行了多年多点试验,并在自然发病条件下,调查了6个品种混种群体对小麦条锈病发生程度的影响.结果表明,小麦品种混种的产量效应平均为+3.9%;小麦品种混种在产量上的正效应、0效应,负效应所出现的频率分别为69.4%、8.3%、22.3%;年份、地点等具体环境条件会影响小麦品种混种的产量效应.在小麦条锈病发病强度相对较高的年份,品种混种可降低条锈病病情指数.因此,品种混种在我国一些小麦产区有利用价值.     

Evaluation of wild Lactuca species for resistance of natural infection of powdery mildew (Erysiphe cichoracearum)

Summary The 99 accessions of seven wild Lactuca species (L. serriola, L. saligna, L. virosa, L. viminea, L. perennis, L. tenerrima, L. tatarica) and Mycelis muralis (syn. L. muralis) were tested for natural infection of Erysiphe cichoracearum L. serriola accessions were highly susceptible. L. saligna showed highly variable levels of resistance. Other Lactuca species were mostly resistant or only moderately susceptible.     

Resistance to powdery mildew in populations of barley landraces from Morocco

Forty-eight populations of barley landraces collected from Morocco were screened for resistance to powdery mildew and a number of different resistance genes were detected. Landraces originated from the collection of the International Center for Agricultural Research in the Dry Areas – ICARDA, Aleppo, Syria. Twenty populations of tested landraces (about 42%) showed resistance reactions and 46 single plant lines were selected. Fourteen of these lines were tested in the seedling stage with 17 and another 32 lines with 23 differential isolates of powdery mildew, respectively. The isolates were chosen according to their virulence spectra observed on the Pallas isolines differential set. Five lines originating from five populations of landraces showed resistance to all prevalent in Europe powdery mildew virulence genes. Thirty-five lines (76%) showed resistance reaction type 2. The distribution of reaction type scores indicated that about 81% of all reaction types observed were classified as powdery mildew resistance (scores 0, 1 and 2). In forty-one lines (89%) the presence of unknown genes alone or in combination with a specific one was detected. Four different resistance alleles (Mlat, Mla6, Mla14 and Mla22) were postulated to be present in the tested lines alone or in combination. Among specific resistance alleles the most common was allele Mlat (resistance Atlas). This allele was postulated to be present in twenty-three (50%) tested lines. The use of new identified sources of resistance to powdery mildew in barley breeding is discussed.     

Transfer of leaf rust and stripe rust resistance from <Emphasis Type="Italic">Aegilops umbellulata</Emphasis> Zhuk. to bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Aegilops umbellulata acc. 3732, an excellent source of resistance to major wheat diseases, was used for transferring leaf rust and stripe rust resistance to cultivated wheat. An amphiploid between Ae. umbellulata acc. 3732 and Triticum durum cv. WH890 was crossed with cv. Chinese Spring Ph ^I to induce homoeologous pairing between Ae. umbellulata and wheat chromosomes. The F₁ was crossed to the susceptible Triticum aestivum cv. ‘WL711’ and leaf rust and stripe rust resistant plants were selected among the backcross progenies. Homozygous lines were selected and screened against six Puccinia triticina and four Puccinia striiformis f. sp. tritici pathotypes at the seedling stage and a mixture of prevalent pathotypes of both rust pathogens at the adult plant stage. Genomic in situ hybridization in some of the selected introgression lines detected two lines with complete Ae. umbellulata chromosomes. Depending on the rust reactions and allelism tests, the introgression lines could be classified into two groups, comprising of lines with seedling leaf rust resistance gene Lr9 and with new seedling leaf rust and stripe rust resistance genes. Inheritance studies detected an additional adult plant leaf rust resistance gene in one of the introgression lines. A minimum of three putatively new genes—two for leaf rust resistance (LrU1 and LrU2) and one for stripe rust resistance (YrU1) have been introgressed into wheat from Ae. umbellulata. Two lines with no apparent linkage drag have been identified. These lines could serve as sources of resistance to leaf rust and stripe rust in breeding programs.     

Molecular diversity of Omani wheat revealed by microsatellites: I. Tetraploid landraces

Results of archaeological studies indicate a millennia-old cultivation history for wheat (Triticum spp.) in Oman. However, in spite of numerous collection surveys and efforts for phenotypic characterization of Omani wheat landraces, no attempts have been made using molecular tools to characterize this germplasm. To fill this gap, 29 microsatellite markers revealing 30 loci were used to study the genetic diversity of 38 tetraploid wheat landrace accessions comprising the species T. dicoccon, T. durum and T. aethiopicum. A total of 219 alleles were detected whereby the number of alleles per locus ranged from 2 to 16 with an average number of 7.1 alleles per locus. The highest number of alleles occurred in the B genome with on average 7.9 alleles per locus as compared to the A genome with 6.5 alleles per locus. Heterogeneity was detected for all microsatellites except for GWM 312, GWM 601 and GWM 192B with an average heterogeneity over all primers and lines of 14.4%. Approximately 10% of the accessions contained rare alleles with an average allele frequency <4%. Gene diversity across microsatellite loci ranged from 0.26 to 0.85. The pairwise comparison of genetic similarity ranged from 0.03 to 0.91 with an average of 0.2. Cluster analysis revealed a clear separation of the two species groups T. dicoccon versus T. durum and T. aethiopicum. Within the species clusters regional patterns of subclustering were observed. Overall, this study confirmed the existence of a surprisingly high amount of genetic diversity in Omani wheat landraces as already concluded from previous morphological analyses and showed that SSR markers can be used for landraces’ analysis and a more detailed diversity evaluation.     

小麦品种混播条件下条锈病发生、扩展研究

在田间分别设计6个小麦品种单播及其9个组合混播小区,研究条锈病在小麦混播群体中的发生、扩展情况及品种混播对条锈病的控制效果。结果表明,苗期品种混播小区发病中心的数量明显减少,条锈病发病中心越冬率达77.78%,单片病叶也可越冬。品种混播降低了条锈病传播距离,条锈病在各小区呈中心式分布。品种混播在孕穗期的相对防效为16.25%～58.89%,平均为35.31%。相对防效以"陕138"和"西农979"品种混播及"陕138"、"小偃22"和"西农889"品种混播最高,分别达58.89%和52.19%。品种混播对小麦条锈病有较好的控制效果,可作为生态防病措施之一。     

Genetic erosion of Ethiopian tetraploid wheat landraces in Eastern Shewa,Central Ethiopia

Ethiopia is a centre of diversity and hosts rich genetic resources of tetraploid wheats. Through time, the wheat materials were subject to genetic erosion. Closer investigation was made to assess the status of loss, and identify the possible causes by studying two districts from East Shewa. Information from primary and secondary sources was reviewed and analysed. Farmers identified 26 tetraploid wheat landraces (21 from Akaki and 17 from Ejere), which were once widely grown in the area. Of these, only six were currently available. Compared to the formerly available number of landraces, the loss of diversity in the study area was estimated to be 77%. In the Ejere locality, the loss was 100% before the launching of the on farm landrace conservation programme, and for Akaki it was 95%. Major factors that contributed to the loss include: (1) introduction and expansion of bread wheat varieties; (2) expansion of tef; (3) lack of a mechanism to re-supply seeds of tetraploid wheat landraces; (4) decline in size of landholdings; (5) changes in land use and cropping patterns; (6) lack of policy support; and (7) expansion of improved tetraploid wheat varieties. The lessons from this study underscore the importance of strengthening the local seed supply system as a prerequisite for sustaining on farm conservation of landraces. Moreover, it is necessary to initiate diversity studies focusing on the distribution and status of tetraploid wheat landraces across the country. Complementing these by molecular analyses is essential in order to assess the genetic distinctness of the landraces.     

小麦抗条锈病基因检测的专家系统研究与设计

小麦条锈病严重危害我国小麦生产,筛选抗病基因培育抗病品种显得尤为重要。针对以往依靠人工进行基因检测费时低效的实际问题,本文研究并设计了小麦抗条锈病基因检测的专家系统,重点介绍了该系统知识库的构建和推理机的设计。     

Variation in Wheat (<Emphasis Type="Italic">Triticum</Emphasis> spp.) Landraces from Different Altitudes of Three Regions of Turkey

Wheat landrace populations, collected from different altitudes of three regions of Turkey, were evaluated for variation within and among populations. Experimental material consisted of 380 accessions, from nine provinces, in Central Anatolian Plateau and North Transitions. The material was grown at Haymana-Ankara Research Farm of Central Research Institute for Field Crops in 1999–2000 planting season, in a three-meter, two-row-plot trial with three bread and three durum wheat checks. Populations were evaluated for plant height, tillers number, spike length, grains per spike, awn length, thousand kernels weight (TKW), winter survival, and days to flowering. Observations and measurements were performed on five randomly selected plants in each plots. Mean, coefficient of variation (CV), and range were computed for populations from five altitude intervals of 0–399, 400–799, 800–1199, 1200–1599, and 1600–1999 m, and geographical regions. Correlation, principal component (CPC) and cluster analyses were performed later. The highest variation was recorded for awn length and the lowest for number of days to flowering. First three principal components (PCs) accounted for 60.69% of the total variation. Cluster analysis for bread wheat, durum wheat, cultivated einkorn and cultivated emmer grouped the species meaningfully.     

Species Diversity in Wheat Landrace Populations from two Regions of Ethiopia

Wheat (Triticum spp.) landrace populations in Ethiopia are mostly species mixtures. However, no quantitative data is available with regard to their species components. We studied here 32 wheat landrace populations originating from two regions (Bale and Wello). A total of 2559 individual plants, 45–110 plants representing each population, were classified into their species components. Five tetraploid (2n = 4x = 28) and one hexaploid (2n = 6x = 42) wheat species were found in mixtures of varying proportions. These included the tetraploids Triticum durum Desf., Triticum turgidum L., Triticum aethiopicum Jakubz., Triticum polonicum L., Triticum dicoccon Schrank and the hexaploid Triticum aestivum L. Also found, however in a rare frequency, in two populations from Wollo was T. durum Desf. convar. durocompactoides Flaksb. (Triticum pyramidale Percival), which is a very dense spiked durum. Discriminant analysis using seven qualitative traits revealed 91.5% correct classification of the wheat species, beak awn and awn length with the most significant importance. Single species were found in eight of the populations; six were for T. durum and two for T. aethiopicum. Two to three species-combinations were the most frequent; a maximum of four species was recorded in one population. The highest diversity index (H′) observed was 0.44. T. durum was the most predominant species. The hexaploid T. aestivum was found in nine of the Wollo populations and, in one population, its frequency reached up to 35.5%. On altitudinal basis, no clear trend of clinal variation was observed both from the frequency distributions and H′ estimates. The results confirmed that Ethiopian wheats, despite the morphological overlaps, could be classified into their species components with high degree of certainty. For the future, therefore, genetic diversity estimations should be dissolved into their species components for more expeditious utilization and conservation of this important genetic resource.     

Identification of new sources for resistance to powdery mildew in H. spontaneum-derived winter barley lines

Twenty four barley lines derived from the F ₇generation of crosses between two winter barley cultivars and different accessions of Hordeum spontaneum Koch collected in Israel were tested against a set of ten European and five Israeli powdery mildew cultures, possessing virulence genes which completely match the spectrum of known mildew resistance genes. The comparison of reaction patterns justified the conclusion that new genes for resistance have been conferred from H. spontaneum which also differ from genes previously identified in other wild barley accessions from Israel. Participation in the expression of the resistance reaction of one of the two barley cultivars used in the development of the lines is well documented in some cases. The majority of the lines was found to be highly resistant against all or almost all European isolates, while various kinds of reactions were observed against the Israeli cultures. The effective transfer of novel mildew resistance from H. spontaneum into winter barley confirms similar results with spring barley, indicating natural wild barley populations in Israel as a significant gene pool for yet unexploited mildew resistance in barley.     

Protein heterogeneity in European wheat landraces and obsolete cultivars: Additional information

The objective of this study was to determine the composition of high molecular weight glutenin subunits of landraces and obsolete cultivars. Altogether glutenin profiles of 67 European wheats were analyzed by sodiumdodecylsulphate polyacrylamide gel electrophoresis. Nineteen of them were observed to be homogeneous, whereas 48 (71%) were heterogeneous in glutenin profiles. Heterogeneous accessions possessed from 2 to 9 different glutenin phenotypes. Seventeen high molecular weight (HMW)-glutenin subunits have been found, three belonged to Glu-1A, 11 to Glu-1B, and three to Glu-1D locus. The most frequented HMW-GS at the Glu-A1, Glu-B1, and Glu-D1 complex loci were 0, 7+9, and 2+12, respectively. However, allele low frequented in wheat such as 13+16, 20, 6, 7, 8, and 9 were observed also. Furthermore, other new alleles encoding HMW-GS at the locus Glu-1B with relative molecular weight 120 and 104 kDa have been found in one of the line of the Swedish cultivar Kotte. TheGlu-1 quality score in the examined accessions varied broadly with some lines reaching the maximum value of 10.     

Resistance to wheat leaf rust in Aegilops tauschii Coss. and inheritance of resistance in hexaploid wheat

A collection of 164 Aegilops tauschii accessions, obtained from Gatersleben, Germany, was screened for reaction to leaf rust under controlled greenhouse conditions. We have also evaluated a selection of synthetic hexaploid wheats, produced by hybridizing Ae. tauschii with tetraploid durum wheats, as well as the first and second generation of hybrids between some of these resistant synthetic hexaploid wheats and susceptible Triticum aestivum cultivars. Eighteen (11%) accessions of Ae. tauschii were resistant to leaf rust among which 1 was immune, 13 were highly resistant and 4 were moderately resistant. Six of the synthetic hexaploid wheats expressed a high level of leaf rust resistance while four exhibited either a reduced or complete susceptibility compared to their corresponding diploid parent. This suppression of resistance at the hexaploid level suggests the presence of suppressor genes in the A and/or B genomes of the T. turgidum parent. Inheritance of leaf rust resistance from the intercrosses with susceptible bread wheats revealed that resistance was dominant over susceptibility. Leaf rust resistance from the three synthetics (syn 101, syn 701 and syn 901) was effectively transmitted as a single dominant gene and one synthetic (syn 301) possessed two different dominant genes for resistance.     

Genotypic variation in field resistance of Cucurbita pepo cultivars to powdery mildew (Erysiphe cichoracearum)

Summary Fifty-eight cultivars of Cucurbita pepo (mostly zucchini type) were studied in three-year experiments for field resistance to powdery mildew caused by Erysiphe cichoracearum. No genotypes were found with complete resistance to powdery mildew. There were significant differences in the expression of field resistance characterized by some basic epidemiological parameters (maximum infection degree, area below curve). The highest level of field resistance occurred in 13 cultivars including Acceste F1, Albina, ambassador F1, CU-235, Elite F1, Goldfinger, Parmanta F1, Seneca Hybr. F1.Abbreviations ABC area below curve - ID infection degree - CO Cocozelle - VM Vegetable marrow - ZU Zucchini