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1.
Summary A total of 280 globe artichoke (Cynara scolymus L.) clones were assessed for reaction to naturally occurring artichoke latent virus (ALV) in field trials. Also, the reaction of 17 seed progenies of crosses which produced ALV-resistant clones in the field, 20 self progenies of parental genotypes common to these crosses, self progenies of 17 artichoke cultivars, and 7 accessions ofC. cardunculus andC. syriaca were evaluated in the glasshouse following mechanical inoculation with ALV. The local and systemic presence of ALV, and the relative virus content in infected plants were determined by ELISA.All cultivars and most of the otherC. scolymus material tested (clones and seed progenies) proved to be highly susceptible to ALV. Ten progenies were less susceptible to mechanical inoculation as shown by the moment the virus could be detected, and a slow rate of accumulation of viral antigen. Some plants in two seed progenies possessed apparently a high resistance as could be concluded from the failure of ALV to spread or to multiply in plant.Accessions ofC. cardunculus andC. syriaca were also highly susceptible to ALV. However, an interspecific hybridC. cardunculus x C. syriaca presented the highest level of resistance, the plants remained free of local and systemic infection. Ratios of resistant to susceptible plants in self progenies of resistant plants suggested that this resistance was dominant. 相似文献
2.
Fifty four varieties of upland cotton (Gossypium hirsutum L.) were screened for resistance to bacterial blight caused by Xanthomonas malvacearum E. F. Smith, (Dowson) under natural field conditions and artificial Inoculation. In general, moderately high levels of field infection provided useful information on susceptibility of varieties but 11 needed to be1 supplemented with artificial inoculation to confirm resistance. Hypocotyl regions of one week-old seedlings were subjected to artificial inoculation with bacterial blight crude isolate using hypodermic needles. None of the fifty lour varieties tested was immune to disease 18.5 % showed a high level of resistance, 29.6 % were recorded as resistant while 20.4 % were susceptible. Another 18.5 % were highly susceptible and 13.0 % showed inconsistent disease reaction under natural field conditions. However, under artificial inoculation the seedlings showed lesions of varied sizes but none of the varieties was found to be resistant. Statistical analysis showed non-significant (P = 0.05) disease interaction indicating susceptibility to disease at the seedling stage. This may be due to lower levels of resistance in seedlings than in mature cotton plants. The resistant varieties were mainly of African origin and well adapted to local conditions. They are therefore potentially useful as commercial varieties in their own right or as donor parents for blight resistance. 相似文献
3.
Greenhouse and field techniques for testing sugar beet for resistance to Rhizoctonia root and crown rot 总被引：1，自引：0，他引：1
Rhizoctonia‐resistant sugar beet varieties are the key to an integrated control strategy for Rhizoctonia root rot. Because of the unpredictable occurrence of Rhizoctonia solani in the field testing of sugar beet for resistance to Rhizoctonia root rot is difficult. The aim of the study was to develop advanced greenhouse and field techniques which allow a reliable assessment of sugar beet for resistance to R. solani. A highly infectious liquid inoculum was used for the first time in this study. It can be produced in large quantities of a standardized quality, sterile, and exactly quantified according to its carbon content. In a greenhouse trial, sugar beet grown in the same way as field grown beet was inoculated by applying a suspension of Rhizoctonia mycelium (equivalent to 10 mg carbon per plant) to the beet crown. After 3 weeks, inoculation had led to uniform and severe root rot. Disease symptoms were similar to those found under natural conditions in the field. No ‘escapes’, i.e. susceptible plants apparently expressing resistance were observed in the test. A new nine‐class disease scale was established and a Rhizoctonia index (RI) was calculated. Reliability of disease assessment was demonstrated on progeny of plants, selected from segregating populations, showing Rhizoctonia resistance more closely related to the resistant parent lines than to the susceptible ones. Sugar beet varieties could be assessed in the greenhouse within only 11 weeks. All varieties were affected by the pathogen but partially resistant varieties could be clearly recognized by a significantly lower Rhizoctonia index. Significant differences in susceptibility were also found within the group of new resistant genotypes. Infection studies performed in the field showed the superiority of the new liquid inoculum compared with a solid form and revealed the influence of inoculation date and inoculum level on the development of Rhizoctonia root rot. In field tests performed at different sites under different environmental conditions, susceptible and partially resistant sugar beet varieties could be reproducibly rated according to their susceptibility to R. solani. On average, susceptible varieties showed a Rhizoctonia index of 8 while resistant genotypes ranged from 5 to 6. The newly developed techniques allow fast and reliable evaluation of sugar beet for resistance to R. solani. 相似文献
4.
Expression of resistance to downy mildew at cotyledon and adult plant stages in Brassica oleracea L.
This research compared the expression of resistance to downy mildew at cotyledon and adult plant stages in seven Brassica oleracea genotypes against two P. parasitica isolates of different virulence. Seven day old seedlings were dual inoculated under controlled environment by depositing
two 10 μl droplets of a spore suspension of a different isolate on each cotyledon and the interaction phenotype (IP) evaluated
7 days later using a 0–5 scale of increasing susceptibility. The seedlings were transplanted to 16 cm pots and grown in the
greenhouse for 110 days (15 to 28 leaves). Adult plants were tested using a single leaf inoculation method that allowed the
same plant to be simultaneously inoculated with the two P. parasitica isolates. Leaves were scored 10 days after inoculation using a 0–5 scale of increasing susceptibility. The inoculation of
the same plant with the two isolates produced different combinations of cotyledon (CT) and adult-plant (AP) interaction-phenotype
according to the genotype. CrGC 3.1 was susceptible at CT and AP stages, ‘Algarvia’ resistant at CT and AP stages, and broccoli
‘A’ susceptible at CT and resistant at AP stage against the two isolates. ‘Murciana’ and broccoli ‘B’ were differential at
CT and AP stages. Savoy and Shetland cabbages were differential at CT stage and resistant to both isolates as adult plants.
Cotyledon resistance could not be used to predict adult-plant resistance since the two types of resistance were very poorly
correlated. Resistance can be race specific either at cotyledon or at adult-plant stage.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
灰皮支黑豆抗大豆胞囊线虫3号生理小种的生化机制研究 总被引：12，自引：1，他引：12
以抗感大豆胞囊线虫3号生理小种品种灰皮支黑豆和辽豆15为研究对象,三叶期后室内人工接种大豆胞囊线虫,接种后5,10,15,20,25,30 d取样,测定抗感品种接种与未接种根内多酚氧化酶(PPO)、过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)活性的动态变化,以及根内次生代谢物质总酚和类黄酮含量的动态变化,进而揭示灰皮支黑豆抗大豆胞囊线虫3号生理小种的生化机制.试验结果表明,大豆受大豆胞囊线虫侵染后,抗感品种根内PPO、POD、PAL酶活性均表现升高,并且在抗病品种灰皮支黑豆中酶活性高峰出现的早,根内总酚和类黄酮含量都表现增加. 相似文献
6.
A set of differential varieties of turnips was grown on three fields infested with Plasmodiophora brassicae
Woron. Gall tissue was collected from diseased roots of some of these varieties. Seedlings of the same varieties were inoculated in the green-house by the application of suspensions prepared from the separate groups of galls. Pathogenic differences between isolates from the same field were observed in some cases. However, when suspensions of the clubs produced in the glasshouse were used as inocula, the differences in pathogenicity between these isolates were much more pronounced. The results of the inoculation experiments indicated the presence of at least two races of the clubroot organism in the same soil and in roots of the same variety. They also showed the selective effect of some of the varieties on the racial mixtures.Some complications and consequences of the method applied to break up racial mixtures into their components were discussed. 相似文献
7.
尖孢镰刀菌毒素对大豆幼根生理生化的影响 总被引：4，自引：0，他引：4
用尖孢镰刀菌毒素处理大豆幼根后,测定其幼根的根活力,细胞渗透性,蛋白质、可溶性糖和脯氨酸含量。结果表明：F. oxysporum毒素对大豆幼根具有强烈的毒害作用,降低大豆根系活力;细胞膜透性增大,且随处理时间的延长和毒素浓度的增加而增大;毒素处理后,前期6h内抗病品种幼根内蛋白质含量降低,感病品种蛋白质含量上升,12h后抗病和感病品种蛋白质含量都降低;抗、感品种的幼苗根系可溶性糖含量明显降低;脯氨酸含量明显增高,感病品种上升的幅度大于抗病品种。 相似文献
8.
A simple method for screening commercial varieties of potato and other wild and cultivated tuber-bearing Solanums for resistance to root knot nematode Meloidogyne incognita (Kofoid and White) Chitwood, has been described. Leaflets taken from plants which were 6 to 8 weeks old are treated with 5 ppm IBA for 24 hours. Treated leaflets, when kept in water, rooted in 12 to 15 days. Use of paper cups, each containing 50 gm of autoclaved soil, was found to be adequate for free development of the roots from the petiole region of the leaflets. Inoculating the soil in the cups with 20 larvae and incubating them at 25°C for 10 days was found to create good conditions for infection of rootlets and subsequent gall formation by the nematodes. The degree of gall formation on the roots was recorded as the grade of susceptibility or resistance of the plant material under test. 相似文献
9.
The reaction of two barley cultivars (‘Thibaut’ and ‘Arizona’) and three lines (AECS 76,‘Tadmor’ and WI 2291) to infection by Cochliobolus sativus was evaluated by three methods. Deep seeding of inoculated seeds was performed in pots and field. Gibberellin (GA3) was applied to inoculated seeds in vitro. Susceptibility assessments were made in vitro at 2 weeks, and in pots at 7 weeks after inoculation, using a scale of 1 (very resistant) to 5 (very susceptible) according to the percentage infected area of the subcrown internodes. There were no differences between the results using the three methods.‘Arizona’ was the most susceptible, whereas ‘Thibaut’ and AECS 76 were partially resistant genotypes. The WI 2291 line and ‘Tadmor’ were moderately susceptible and moderately resistant, respectively. In vitro tests yielded the same order as tests from pot and field experiments. 相似文献
10.
High frequency direct plant regeneration from leaf and petal explants was accomplished for the first time in Streptocarpus varieties. The shoot induction frequency varied with respect to the benzylaminopurine (BAP) concentration added to the Murashige
and Skoog (MS) medium. MS medium with 0.5 mg l−1 BAP exhibited the highest (69.9%) plant regeneration frequency with an average of 186 shoots per explant. A higher concentration
of BAP inhibited shoot bud induction and plant regeneration along with necrosis of explants. Petal explants derived from the
varieties ‘Branwen’ (pink and white) and ‘Chorus Line’ (violet and white) displayed plant regeneration frequency of 22.2–47.4%
(within a total of 12 weeks) on MS medium containing 2.0 mg l−1 α-naphthaleneacetic acid and 0.5 mg l−1 BAP for 8 weeks followed by 4 weeks on MS medium with 1.0 mg l−1 BAP. Scanning electron microscopy confirmed direct plant regeneration without callus. Regenerated plants from leaf explants
with well-developed leaves and roots were hardened and successfully transferred to pots in glasshouse exhibiting 86% survival
at the end of 4–6 weeks. Whereas, regenerated plants from flower petal explants upon transfer to pots in glasshouse exhibited
75–82% survival at the end of 4–6 weeks. 相似文献
11.
黄瓜感染白粉病菌后的生理变化 总被引：8，自引：1，他引：7
抗性不同的黄瓜品种接种白粉病菌后,对与抗性有关的光合作用、呼吸强度及叶绿素、可溶性糖、可溶性蛋白质的含量进行了测定。结果表明:抗病品种呼吸强度比对照明显升高,感病品种则低于对照;抗、中抗品种光合速率先升高,5~6 d后开始下降,而感病品种的光合速率基本上低于对照,这与呼吸强度的变化相一致;无论抗病品种还是感病品种叶绿素含量均有增加,抗病品种增加幅度更大,说明黄瓜抗白粉病的能力与叶绿素含量呈正相关;接种后各品种糖含量的变化趋势基本一致,即降低-升高-再降低-再提高,而且均在第5 d出现第1个峰值,第7 d则出现最大幅度下降,可溶性糖含量明显低于对照,说明病菌的侵染消耗植株体内的糖,但并不能说明糖含量的降低与品种的抗病性密切相关;各黄瓜品种叶片可溶性蛋白质含量均高于对照,但感病品种比抗、中抗品种的峰值出现的要早,说明感病品种对病菌的侵染更敏感,品种的抗病性与对病菌侵染的反应呈负相关。 相似文献
12.
The nature and extent of hybrid vigour and inbreeding depression were estimated from a diallel set of rice varieties. The seven parents and their 21 F1 s and 21 F2 s were grown in pots with four replications. Data were collected on four root and two shoot characters.
Maximum heterosis was recorded for root weight followed by roots/plant and root length. The inbreeding depression did not significantly affect the dry root weight in majority of the crosses. Heterosis for shoot weight was found to be associated with the heterosis for roots/plant and root weight. 相似文献
Maximum heterosis was recorded for root weight followed by roots/plant and root length. The inbreeding depression did not significantly affect the dry root weight in majority of the crosses. Heterosis for shoot weight was found to be associated with the heterosis for roots/plant and root weight. 相似文献
13.
A method employing simultaneous inoculation with TMV (tobacco mosaic virus) and PVX (potato virus x) was compared with the conventional TMV inoculation in tests with known susceptible, resistant and segregating lines and varieties of tomato seedlings. While inoculation with TMV alone caused 63 to 88 percent systemic symptoms in known susceptible seedlings, the double virus method resulted in 100 percent necrotic streak and stunt. In advanced resistant lines such symptoms were entirely absent and when tested in the field against heavy TMV infection were found to be highly resistant. Thus, it appears that resistance to TMV in these derivatives of Lycopersicon hybrids can be decisively evaluated by the double virus inoculation method.Associate Professor of Plant Pathology, Department of Botany and Plant Pathology, Michigan State University. East Lansing, Michigan.Associate Professor of Horticulture, Department of Horticulture, Michigan State University. Journal Article No. 3100, Michigan Agricultural Experiment Station. 相似文献
14.
为了获得具有抗马铃薯晚疫病的品种,本研究以100份马铃薯种质资源为试材,采用室内离体叶片接种法和室内成株接种法进行晚疫病抗性评价,用高感品种Favorita接种后的症状为对照。室内离体接种鉴定结果为:‘CIP09-2’、‘CIP09-13’、‘DR-6’、‘DR-9’、‘花云’、‘R1R3’、‘云薯501’、‘R2’、‘BE13-3’等9份材料表现为高抗,占供试材料的9%;其它的15份表现中抗、44份表现抗病、23份表现感病和9份表现高感。欧氏距离类平均法聚类分析表明,聚为抗性品种的种质最多,其来源与马铃薯晚疫病的抗性没有太大关系。本研究对其中4份材料进行室内成株接种,结果表明:‘青薯10号’的抗病性高于离体叶片接种的抗性,为高抗品种;‘青薯9号’、‘2017ch-6’和‘费乌瑞它’抗性表现与离体叶片接种抗性鉴定结果一致。本研究发现所有供试马铃薯种质资源的抗性材料较丰富,可为抗病育种提供优质的亲本材料。 相似文献
15.
中国小黑豆抗源对大豆孢囊线虫4号生理小种抗病的生化反应 总被引：14，自引：0，他引：14
抗源品种灰皮支黑豆、元钵黑豆和高感品种鲁豆１号为供试大豆材料，大豆孢囊线虫４号生理小种卵和二龄幼虫为接种物。接种后１７天，测定大豆根部的营养物质和次生代谢物含量。与不接种对照比，抗源品种灰皮支黑豆和元体黑豆根部的总糖含量分别降低２４．９１％和３７．７７％，而感病对照鲁豆１号升高４６．０１％；果糖和麦芽四糖含量在感病对照根上增加幅度较大，分别为１４４．３０％和６２．９０％，但在抗源品种根上或是具有小 相似文献
16.
17.
E. Drijfhout 《Euphytica》1968,17(2):224-235
Summary Different aspects of pea leafroll, the most important virus disease of peas and Vicia-beans in The Netherlands, are discussed. These aspects include the spread of the virus, the damage done by the disease, the symptoms, the nature of the virus, the vectors and the host plants. Pea leafroll virus (PLRV) is a persistent virus which is invariably transmitted by aphids. The most important vector is the pea aphid, Acyrthosiphon pisum
Harris. Lucerne actas as a winter host for the virus and the pea aphid. The pea aphids are reared on diseased lucerne plants and are used in a glass-house experiment to test cross populations for resistance. In view of its importance for that test it is necessary to discuss the biology of the pea aphid in some detail. Besides the glasshouse test some field test methods are mentioned.Crosses between Cobri (resistant) and Gloire de Quimper (susceptible) as well as between Wyola (resistant) and Joserva (susceptible) served to study the resistance to the virus in peas. The results of testing well over 3600 plants justified the conclusion that the resistance is inherited as a single recessive character. It is suggested to refer to the gene for susceptibility to PLRV as Lr. 相似文献
18.
19.
In order to determine the effects of bunt inoculation on frost resistance and winter hardiness in lines containing resistance
genes, the bunt [Tilletia foetida (Wallroth) Liro, T. caries (DC.) Tulasne] susceptibility of wheat lines containing bunt resistance genesBt1 to Bt10 and the effect of the year on the degree of infection were studied over six years from 1991 to 1997 in an artificial inoculation
nursery. Uninoculated and artificially inoculated wheat plants were tested for frost resistance in the phytotron in 1995 and
in the field in boxes in three years from 1994/95 to 1996/97. The line withBt10 was very resistant, lines with Bt5, Bt6, Bt8 and Bt9 were resistant, the line with Bt4 was moderately resistant, those with Bt2 and Bt3 were moderately susceptible, the line with Bt1 was susceptible and the line with Bt7 was very susceptible to the local bunt population in Hungary. Bunt incidence also varied over years. The frost resistance
of the Bt lines was generally lower after bunt inoculation than that of uninoculated plants. The increased frost kill in inoculated
plants was not correlated with the extent of varietal susceptibility to bunt. Some lines with resistance, namely those with
Bt5 (1.6% infection), Bt8 (0.6%) and Bt10 (0.0%), suffered significantly greater frost kill in the young plant stage as the result of bunt inoculation. By contrast,
the Bt7line had excellent frost resistance and winter hardiness but suffered the greatest extent of bunt infection, whereas the Bt6 line had good frost resistance and good bunt resistance.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
Three studies were initially conducted using five mint cultivars with known disease reactions to verticillium wilt to determine
if inoculation method, root-dip as compared to root-injection, had an affect on the plant growth and disease reaction. The
planting media did not affect the development of wilt symptoms in susceptible varieties, however, the soil/peat based medium
resulted in higher shoot fresh weight at harvest than the perlite/vermiculite medium. Black Mitcham had the highest susceptible
disease rating and greatest reduction in fresh shoot weight from inoculation with Verticillium dahliae at two inoculum concentrations,
104 or 106 microconidia/ml. Native spearmint was resistant and Mentha crispa was moderately resistant, whereas, Murray Mitcham
peppermint and Scotch spearmint were moderately susceptible to verticillium wilt with a corresponding lower fresh shoot weight.
Scotch spearmint was less susceptible at the low inoculum concentration than at a higher level of microconidia, indicating
a low level of disease resistance. Overall, the two inoculation methods resulted in similar cultivar responses to verticillium
wilt, although the root-injection method was more applicable for large plant populations. Thus, the root-injection method
of inoculation was utilized to screen 743 Black Mitcham derived somaclones for wilt resistance, of which nine somaclones were
found resistant in repeated inoculation tests.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献