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1.
Ergot or sugary disease of sorghum has become an important constraint in North and South American countries that rely on F1 hybrid seeds for high productivity. The objective of this research was to determine the vulnerability of various germplasm sources and publicly bred sorghum lines to sugary disease ( Claviceps africana ) in the United States. Flower characteristics associated with sugary disease resistance were also studied. A-/B-line pairs, R-lines, putative sources of resistance and their hybrid combinations with an A3 cytoplasmic male-sterile source were evaluated using a disease incidence, severity, and dual-ranking system. Trials were planted in a randomized complete block design with three replications and repeated in at least two planting dates. Planting dates and pedigrees had significant effects on overall ranking for resistance. A-lines were most susceptible to sugary disease. R-lines were more susceptible than B-lines with respect to incidence and severity of the disease. Newer releases of A- and B-lines were more susceptible to sugary disease than older releases. Sugary disease reaction of A-lines was a good indicator of disease reaction of B-lines. Tx2737, a popular R-line, was highly susceptible to sugary disease in spite of being a good pollen shedder because the stigma emerged from glumes 2–3 days before anthesis. The combination of flower characteristics associated with resistance were least exposure time of stigma to inoculum before pollination, rapid stigma drying after pollination, and small stigma. An Ethiopian male-fertile germplasm accession, IS 8525, had good levels of resistance. Its A3 male-sterile hybrid had the highest level of resistance in the male-sterile background. IS 8525 should be exploited in host-plant resistance strategies.  相似文献   

2.
酿酒高粱品种、组合及亲本的丝黑穗病抗性鉴定   总被引:1,自引:0,他引:1  
为了明确不同类型的酿酒高粱材料对西南地区丝黑穗病的抗性和促进抗丝黑穗病品种的选育,采用土壤接菌法对107份材料进行了丝黑穗病抗性鉴定;根据抗性鉴定结果,比较了酿酒高粱杂交组合与其亲本对丝黑穗病的抗性,并对供试菌种进行了致病力分析.结果显示:在感病对照恢1植株平均病株率为67.65%时,有13个不育系、6个保持系、10个恢复系、28个杂交组合的病株率为0,达免疫水平,其中,酿酒高粱不育系和杂交组合所占比例较大,分别为86.67%和75.68%;恢复系中免疫类型所占比例较小,为24.39%;常规品种和组合中无免疫类型;杂交高粱对丝黑穗病的抗性属显性遗传;泸州丝黑穗病菌具有较强的致病力.  相似文献   

3.
从配合力分析探讨甘蔗家系抗黑穗病的育种潜力   总被引:2,自引:0,他引:2  
采用5×4不完全双列杂交设计选配的第1次无性种茎为试验材料,在人工浸渍接种黑穗病菌条件下,估算了9个亲本及其组合在新植蔗和宿根蔗的配合力效应。结果表明:①20个家系抗性差异较大,以CP67/412、ROCl为母本的半同胞家系表现较强抗病性,而以CP72/1210、CP65/357为母本的半同胞家系表现一定感病性;②甘蔗抗黑穗病遗传是由加性效应基因和非加性效应基因共同控制;③发现CP67/412、ROClgca效应值较高,CP57/614次之,均具有可作为抗源亲本的育种潜力,④根据配合力总效应值评价组合,认为CP67/412×崖84/153、ROCl×崖71/374、CP67/412×崖71/374、ROCl×崖84/153、CP67/412×崖73/512、CP57/614×崖84/153是抗黑穗病较强的组合,可用于今后抗黑穗病育种计划。  相似文献   

4.
利用分子标记辅助选择技术提高玉米对丝黑穗病的抗性   总被引:4,自引:1,他引:3  
为了探索分子标记辅助选择(MAS)技术在抗玉米丝黑穗病育种中的应用效果,以吉1037为抗源,吉单209的感病母本8902为轮回亲本,回交5代后,自交2代,从BC4F1开始利用MAS技术把感玉米丝黑穗病的亲本8902改良成抗病自交系,并与吉853配制杂交种,对其进行抗病性、产量和农艺性状评价。改良后的8902及其组合,对玉米丝黑穗病的抗性和产量显著提高,且其它农艺性状没有发生改变。抗性以上自交系超过获得材料的80%以上,抗性以上杂交组合超过配制组合的77%以上;改良后亲本组配的杂交种产量较对照明显增加,11个杂交组合增产10%以上,最大增幅可达26.7%。研究表明MAS技术显著提高了自交系及其杂交种对玉米丝黑穗病的抗病效果。  相似文献   

5.
A refined inoculation method to evaluate false smut resistance in rice   总被引:1,自引:0,他引:1  
False smut, caused by Ustilaginoidea virens, is a serious disease of rice worldwide. To evaluate false smut resistance in rice, we developed a method combining the cultivation of the main culm of rice plants in the greenhouse and rapid preparation of a conidial suspension to inject into the leaf sheath. The method was used to evaluate false smut resistance in 18 varieties/lines of rice. For comparison, field trials were also carried out in 2007 and 2008. The results indicated that the greenhouse method was more reproducible than field trials: commercial varieties tested were resistant; almost all the forage varieties were highly susceptible; and blast-resistant varieties/lines were mostly resistant to false smut. Thus, this inoculation method will be useful for determining the level of false smut resistance in rice and for breeding resistant varieties.  相似文献   

6.
Y. PARLAK 《EPPO Bulletin》1981,11(2):83-86
The important seed-borne diseases of wheat in Turkey are common bunt ( Tilletia caries and T. foetida ), loose smut ( Ustilago nuda tritici ), dwarf bunt ( T. contraversa ) and flag smut ( Urocystis tritici ). Seed treatment against common bunt is widely used in Turkey. The damage is about 10–15 %, sometimes 90 % in some fields where seeds are sown without treatment. About 10 % of wheat fields were infected with bunt during 1972–1974. Seed treatment with carboxin (Vitavax) is recommended against loose smut of wheat in Turkey, but has not yet been used. Some wheat varieties, especially Siirak (1593/51) wheat, are highly susceptible to loose smut. The proportion of smut-infected heads reached 30–40 % in this variety and about 32 % of wheat fields were infected with loose smut during 1972–1974. The damage was about 6 % in infected fields. Yield losses were at least 35,000 tons. Dwarf bunt is distributed at high altitude (1300–2000 m) in eastern Turkey; 2500 ha of wheat fields are infected with dwarf bunt. The disease causes 1–80 % losses in some fields. The wheat variety Yayla 305 is recommended for infected areas. Flag smut is present in some areas of Turkey, but yield losses are not important. Seed treatment is effective against seed-borne spores.  相似文献   

7.

Pathogens are generally expected to evolve faster than their hosts and are therefore likely to be locally adapted. However, some pathogens might lag behind in the co-evolutionary arms race because they do not have some of the advantages shared by most other pathogens (e.g., high mutation or recombination rates, short generation time, high dispersal ability). This is the case of Microbotryum fungi that cause the anther smut disease in plants of the family Caryophyllaceae. We investigated the patterns of local adaptation and maladaptation in Microbotryum carthusianorum and its host plant Dianthus carthusianorum. We performed a full cross-inoculation experiment using half-sib plant families and fungal samples originating from three naturally infected populations in the Czech Republic. We specifically asked, which components of pathogen fitness (i.e., infectivity and host manipulation) are affected by local (mal)adaptation. The pathogen was on average 1.6 times more successful in infecting plants from foreign populations compared to plants from its home population. Once the infection was successful, the pathogen accelerated the plant’s flowering and thus increased the opportunity for transmission to new hosts. However, the level of manipulation of host flowering did not differ between home and foreign populations. This study showed that the pathogen’s infectivity followed a clear pattern of local maladaptation, whereas the host manipulation did not. Our study taken together with previous studies of a related anther smut species reveals the pervasiveness of local maladaptation in this group of pathogens that arises as the result of their restricted gene flow and reduced recombination rates.

  相似文献   

8.
 作者在玉米品种资源对丝黑穗病抗性鉴定的基础上,用6个抗性不同的自交系,按双列杂交设计,进行了玉米对丝黑穗病抗性配合力和遗传力的研究。结果表明:玉米对丝黑穗病的抗性遗传主要受加性基因控制。不同玉米自交系之间的抗性配合力存在着极显著差异。故在玉米抗丝黑穗病育种时,既要重视抗原的筛选,又要对抗原进行抗病性配合力的测定。  相似文献   

9.
稻曲病的接种技术研究   总被引:23,自引:0,他引:23  
 探索在田间条件下进行稻曲病的人工接种技术。通过比较3种接种体发现,上年保存于-20℃的厚垣孢子不能引起发病;用PS液体培养获得的薄壁分生孢子可引起发病,孢子浓度越高引起病穗率越高;菌丝片段-分生孢子混合液接种发病最严重。病原菌的培养菌龄对接种效果有影响。在水稻的3个时期接种,以抽穗破口前6~9d的效果最好。在一天的3个时段接种,以下午4~6时的病情最重。在接种液里添加马铃薯煮汁可显著提高接种发病率。本文的接种技术能高效引发稻曲病,最高穗发病率100%,最大病情指数93.96,最多穗病粒数110粒。该接种技术可鉴别出品种抗病性的差异。  相似文献   

10.
杂交稻制种粒黑粉病的侵染源及发生规律   总被引:1,自引:0,他引:1  
1989-1993年对稻粒黑粉病(Neovossia horrida)的侵染源和发生流行规律进行了系统研究。结果表明,由冬孢子萌发直接产生的次生担孢子不是田间发病的主要接种体。发现并证实稻粒尾孢墨 粉菌具有在植物体表芽殖附生特性,其病害特占存在一个相当长的田间芽殖附生阶段,芽殖附笺次生担孢子才是田间发病的有效接种体。不育系柱头外率主、开发时间持续长而分散及恢复系花粉量是导致发病严重的主要寄生因素。  相似文献   

11.
玉米丝黑穗病原菌侵染的一些细胞学研究   总被引:7,自引:1,他引:7  
 在玉米生育早期,以幼芽鞘为材料,对11个抗病性不同的自交系进行了研究。玉米丝黑穗病原菌[Sphacelotheca reiliana (Kühn) Clint var.zeae Pass]可在玉米幼芽鞘内表皮上生长和繁殖;其侵染菌丝可直接侵入表皮细胞或通过气孔进入寄主体内。菌丝的侵入诱导了芽鞘内表皮细胞的细胞壁、细胞质和细胞膜特性的异常变化;抗性不同的自交系对病原菌侵入的反应不同,揭示了在生育早期玉米芽鞘细胞就表现了其固有的抗病性。  相似文献   

12.
We investigated the optimal timing of simeconazole (RS-2-(4-fluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-3-trimethylsilylpropan-2-ol) application for controlling rice kernel smut in field trials in Miyagi Prefecture, Japan, using formulations of simeconazole (1.5% granules). The field tests revealed that a submerged application of simeconazole granules (450–600 g ai/ha) at 1–5 weeks before heading was highly effective against kernel smut, with treatments 1–2 weeks before heading being the most effective. Submerged application of the fungicide at 2–5 weeks before heading was also highly effective against false smut, with treatment 3 weeks before heading being the most effective. These periods overlap the timing for optimal application of simeconazole to control rice sheath blight and ear blight. Consequently, we concluded that treatment with simeconazole 2–3 weeks before heading can be a useful tool for controlling all four diseases.  相似文献   

13.
Forty-two registered spring barley cultivars from the German official list were tested under natural infection conditions for susceptibility to loose smut (Ustilago tritici f.sp. hordei) during two test cycles at two locations. Only cv. Steffi was found to be resistant to the local loose smut population. Cultivar Sigrid showed lowest susceptibility because of flowering inside the leaf sheath. Less than 1% infection at all sites showed up in cvs Auriga, Jacinta and Hendrix. Twenty-one cultivars had an infection rate of less than 2%. Cultivar Danuta displayed the highest susceptibility with an average of 12.6%. Another 23 spring barley accessions with expected loose smut resistance were inoculated artificially with loose smut populations obtained from 11 locations in Germany and neighbouring countries. Only Jet with the resistance Un3/6, CDC Freedom with Un8, CIho9973 with quantitative resistance, as well as Lino and GangTuoQuingKeHao1 remained disease-free. In addition to these, another eight accessions in this test group are recommended to become part of a differential tester set to distinguish origins of loose smut. Statistical analysis showed that for scoring of cultivars more importance has to be given to the number of locations for infestation than to the number of test locations to determine the degree of attack. In view of the existing inspection limits for production of certified seed in European countries, the currently registered German barley cultivars put organic seed producers and breeders at high risk in respect to loose smut infection, if the number of generations for multiplication under organic farming increases.  相似文献   

14.
False smut, caused by Ustilaginoidea virens, is a rice disease of increasing importance worldwide, with no source of high‐level resistance in the existing rice germplasm. To facilitate breeding varieties with good levels of field resistance to false smut, quantitative resistance loci (QRL) were identified using 213 introgression lines (ILs) from a cross between Teqing (recipient) and Lemont (donor) evaluated using natural infection at two hotspots of false smut in northeast China. Ten QRL affecting percentages of diseased hills, diseased panicles and diseased spikelets were detected and mapped to rice chromosomes 2, 3, 4, 6, 8, 10, 11 and 12. The Lemont alleles at all QRL increased false smut resistance. Four QRL (qFSR‐6‐7, qFSR‐10‐5, qFSR‐10‐2 and qFSR‐11‐2) had relatively larger and consistent effects across the two testing sites. Promising resistant ILs were identified, most of which had multiple QRL, suggesting that pyramiding multiple QRL by marker‐assisted selection would be an effective strategy for improving rice resistance to false smut. The identified QRL and their linked DNA markers will facilitate this breeding effort in the future.  相似文献   

15.
Seed-feeding by larvae of the mosquito head fly, Melanagromyza minimoides, can substantially reduce yields of late-planted sunflower in South America and its management with insecticides or early-planting has other undesirable costs. Evaluation of inbred lines over three seasons indicated differences in the emergence of adult flies, particularly between restorer (male) and maintainer (female) lines used for hybrid seed production; when fly emergence (≈damage) was adjusted for differences in head size (i.e. to flies/100 cm2), restorer lines averaged 3–12 times more damage than maintainer lines. Fly emergence in each of two seasons was tested for correlations with three sunflower traits (glandular trichome number, pericarp strength, and sesquiterpene lactone content) believed to provide host plant resistance to other insects. In one of two years, fly emergence was negatively correlated with the relative amount of sesquiterpene lactones in florets of the tested lines. Also, among maintainer lines, severity of infestation was much greater in multi-headed inbreds compared to single-headed lines. Additional research is needed to establish the cause(s) of reduced susceptibility of inbreds and whether parental lines influence M. minimoides damage to hybrids.  相似文献   

16.
Spring wheat seedlings containing Lr 20 and Sr 15 resistance alleles were raised at 30° C, prior to inoculation with leaf rust ( Puccinia recondita race 76–2,3) and stem rust ( Puccinia graminis f.sp, tritici race 343–1,2,3,5,6) pathogens, respectively. Infected plants were then grown at one of seven temperatures in the range 18–30 C and infection types were scored at 10 days post-inoculation. These results were compared with those obtained for plants raised at a pre-inoculation temperature of 18° C. In both 18° C and 30° C pre-grown plants, a progressive increase in infection type was observed on resistant lines as post-inoculation temperature increased. However, resistant lines raised at 30°C had significantly higher infection types than plants raised at 18° C at all post-inoculation temperatures for which some degree of resistance was still evident in the plants raised at 18°C, The maximum temperature for expression of resistance was significantly higher for Lr 20 than for Sr 15. irrespective of pre-inoculation temperature. A lowering of the resistance expression was also evident in Sr 15 -bearing lines raised at a very low pre-inoculation temperature (4°C). The effects of low pre-inoculation temperature on resistance were assessed in both winter and spring wheat lines. These results are discussed in the light of current ideas concerning the host membrane location of pathogen recognition events.  相似文献   

17.
Wilson JP  Hess DE  Hanna WW 《Phytopathology》2000,90(10):1169-1172
ABSTRACT Resistance to Striga hermonthica in 274 wild Pennisetum glaucum subsp. monodii and stenostachyum accessions was evaluated at Samanko, Mali in 1997 and 1998, and at Cinzana, Mali and Sadoré, Niger in 1998. Data recorded included number of striga plants per plot at least three times during the season, date of striga emergence, number of Pennisetum plants, Pennisetum anthesis date, and downy mildew incidence (caused by Sclerospora graminicola). Across trials, the average maximum number of striga per host plant ranged from 0.9 to 8.3. Average days to striga emergence ranged from 54 to 68 days across trials, and was negatively correlated (P < 0.01) with maximum striga within trials. Days to Pennisetum flowering ranged from 54 to 74 days across trials. Host flowering was correlated (P 相似文献   

18.
Variation in resistance to Ascochyta fabae among winter-hardy genotypes of faba bean was demonstrated in artificially inoculated field trials. The incidence of seed infection after harvest was strongly correlated with both foliar and pod infection. Joint regression of the incidence of pod infection on flowering date and length of straw accounted for 33–56% of the variance but this largely reflected the behaviour of the entries with a determinate habit which were very susceptible and sensitive to infection by A. fabae. Two indeterminate lines which were similar to each other in flowering date and straw length contrasted greatly in the incidence of foliar and pod infection.  相似文献   

19.
Phenological events for desert plants were recorded and rainfall and temperature data were gathered over a three-year time scale at a gravel plain in the eastern region of the United Arab Emirates. Variations of phenological periods were analyzed and correlations between phenological periods and climate factors were discussed. The study showed that the growth and flowering of therophytes were significantly correlated with air temperature. The timing and abundance of rainfall came to be another factor significantly correlated with the onset and duration of chamaephyte flowering as well as the duration of therophyte growth and flowering. The variation in rainfall did not affect the onset of flowering in phanerophytes. Peak growing seasons were from November to March and flowering from November to December(also February to March depending on the availability of rainfall). Flowering in phanerophytes and chamaephytes occurs 4–6 weeks and in therophytes 4–8 weeks after rain. The results showed that variations in growth and phenology between species were correlated with environmental factors, such as temperature and rainfall or, maybe, differences in life form and photosynthetic pathways, each being adapted for utilizing a particular phase of the seasonally and yearly variable rainfall. The sequence of flowering for the species under study was more or less constant despite the difference in the amount of rainfall. The fruiting patterns of most of the species were also found parallel to their flowering patterns. Our results emphasized the need to study multiple species at many sites for the understanding and forecast of regional changes in phenology.  相似文献   

20.
Weng J  Liu X  Wang Z  Wang J  Zhang L  Hao Z  Xie C  Li M  Zhang D  Bai L  Liu C  Zhang S  Li X 《Phytopathology》2012,102(7):692-699
The major quantitative trait locus (QTL) qHS2.09 plays an important role in resistance to head smut during maize breeding and production. In this study, a near-isogenic line (NIL), L34, which harbors the major QTL qHS2.09 in bin 2.09, was developed using a resistant donor 'Mo17' in a susceptible genetic background 'Huangzao4'. Using 18,683 genome-wide polymorphic loci, this major QTL was finely mapped into an interval of ≈1.10 Mb, flanked by single nucleotide polymorphism (SNP) markers PZE-102187307 and PZE-102188421. Moreover, the favorable allele from 'Mo17' for SNP PZE-102187611 in this interval that was most significantly associated with resistance to head smut (P = 1.88 E-10) and accounted for 39.7 to 44.4% of the phenotypic variance in an association panel consisting of 80 inbred lines. With combined linkage and association mapping, this major QTL was finally located between SNP PZE-102187486 and PZE-102188421 with an interval of ≈1.00 Mb. Based on the pedigrees of 'Mo17' and its derivatives widely used in temperate maize breeding programs, the favorable haplotype from 'Mo17' is shown to be the main source of resistance to head smut in these lines. Therefore, the SNPs closely linked to the major QTL qHS2.09, detected in both linkage and association mapping, and could be useful for marker-assisted selection in maize breeding programs.  相似文献   

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