Nodulation of subterranean clover growing in permanent pastures on acid soils in North-Central Victoria

1986 ◽  
Vol 26 (1) ◽  
pp. 31 ◽  
Author(s):  
HR Jones ◽  
BC Curnow
Keyword(s):  
Root Rot ◽  
Acid Soils ◽  
Subterranean Clover ◽  
Rhizobium Trifolii ◽  
Soil Factors ◽  
North Central ◽  
Exchangeable Calcium ◽  
Central Victoria ◽  
Clover Root

A survey ofclover at 44 sites in permanent dryland pastures in North-Central Victoria, highlighted poor nodulation of subterranean clover.In 1982 and 1983 respectively only 40 and 62% of plants were effectively nodulated 8-10 weeks after germination of the clover. Clover root rot was also present in both years, 64% of plants being affected in 1982 and 14% in 1983. Nodulation was negatively correlated with the incidence of root rot and with the percentage of exchangeable aluminium in the soil and positively correlated with the percentage of exchangeable calcium in the soil. The number of Rhizobium trifolii in the soil was not correlated with any of the soil factors measured.

The in vitro inhibition of Phytophthora clandestina by some rhizobia and the possible role of Rhizobium trifolii in biological control of Phytophthora root rot of subterranean clover

1999 ◽  
Vol 50 (8) ◽  
pp. 1469 ◽  
Author(s):  
S. Simpfendorfer ◽  
T. J. Harden ◽  
G. M. Murray
Keyword(s):  
Biological Control ◽  
Root Rot ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Root Disease ◽  
Rhizobium Trifolii ◽  
Biological Control Agents ◽  
Control Activity ◽  
Phytophthora Root Rot

The interaction between 29 isolates of Rhizobium and the in vitro growth of 3 strains of Phytophthora clandestina was investigated to determine the potential of these bacteria as biological control agents against root rot of subterranean clover (Trifolium subterraneum L.). The biological control activity of Rhizobium on the severity of root disease in seedlings was also investigated under glasshouse conditions. Thirteen of the 29 Rhizobium isolates caused significant reductions in the hyphal growth of the 3 P. clandestina isolates examined. Inoculation of seedlings with Rhizobium trifolii reduced the severity of root disease by 14–58% with corresponding increases in dry matter production of 20–73%. These results indicate that Rhizobium species have potential as biological control agents against the root rot of T. subterraneum seedlings caused by P. clandestina.

Effects of soil pasteurization on root rot, seedling survival and plant dry weight of subterranean clover inoculated with six fungal root pathogens

1987 ◽  
Vol 38 (2) ◽  
pp. 317 ◽  
Author(s):  
MJ Barbetti ◽  
K Sivasithamparam
Keyword(s):  
Root Rot ◽  
Seedling Survival ◽  
Lateral Roots ◽  
Subterranean Clover ◽  
Dry Weight ◽  
Plant Size ◽  
Natural Soil ◽  
Virgin Soil ◽  
Pythium Irregulare ◽  
Clover Root

Subterranean clover was exposed to two levels of inoculum of millet seed colonized by Fusarium avenaceum, Fusarium oxysporum, Phoma medicaginis, Phytophthora clandestina, Pythium irregulare, or Rhizoctonia solani within pasteurized and unpasteurized field soil from sites with (root rot site) and without (virgin site) a history of subterranean clover root rot at Augusta, W.A., with the aim of establishing their pathogenicity in the presence of other soil organisms including resident pathogens. Introduction of F. avenaceum (2.5% w/w), P. clandestina (0.5 and 2.5%), P. irregulare (0.5 and 2.5%), or R. solani (0.2 and 1.0%) increased damage to tap and lateral roots of subterranean clover in pasteurized and unpasteurized root rot and virgin soils. All fungi tested, with the exception of P. medicaginis (2.0 and 10.0%) or P. medicaginis (2.0 and 10.0%) and F. oxysporum (0.5 and 2.50%), caused reduction of seedling survival in pasteurized root rot and virgin soils respectively. When the soil was unpasteurized, all fungi except F. oxysporum (2.5%) and P. medicaginis (2.0 and 10*0%) in virgin soil, but only P. irregulare (2.5%) or R. solani (0.2 and 1.0%) in root rot soil, reduced seedling survival. In unpasteurized soils plant dry weight was reduced by P. clandestina (2.5%), P. irregulare (0.5 and 2.5%), or R. solani (0.2 and 1.0%) in root rot and virgin soils, but F. oxysporum (0.5%) reduced plant size only in the root rot soil. Within pasteurized soil all fungi, with the exception of P. medicaginis (2.0 and 10.0%) in virgin soil and F. avenaceum (2.5%), P. irregulare (0.5 and 2.5%), or R. solani (0.2%) in root rot soil, caused reduction in plant size. P. clandestina, P. irregulare or R. solani, in particular, and to a lesser extent, P. avenaceum, are capable of causing serious damage to subterranean clover in natural soil.

Fusarium avenaceum, a seed-borne pathogen of subterranean clover roots

1974 ◽  
Vol 25 (4) ◽  
pp. 549 ◽  
Author(s):  
DC McGee ◽  
AW Kellock
Keyword(s):  
Root Rot ◽  
Laboratory Tests ◽  
Subterranean Clover ◽  
Fusarium Avenaceum ◽  
Seed Infection ◽  
Highly Pathogenic ◽  
Infected Seed ◽  
Clover Root ◽  
First Time

Fusarium avenaceum (Corda ex Fr.) Sacc. has been shown for the first time to be a seed-borne pathogen of subterranean clover (T. subterraneum L.). In laboratory tests symptoms of subterranean clover root rot occurred on plants grown from infected seed. F. oxysporum (Schlecht.) also was seed-borne. It was only weakly pathogenic, although isolated more frequently from diseased roots than F. avenaceum. Pythium sp. was not detected on seed and rarely isolated from roots of diseased field plants, but it was highly pathogenic to subterranean clover roots in laboratory tests. F. avenaceum was detected in 81 out of 85 seed lines tested, which comprised 11 cultivars, from four Australian States. Infection with F. avenaceum occurred on up to 27% of the seed in a sample. An application of benomyl (0.63 g/kg seed) controlled seed infection.

Interactions of surface drying and subsurface nutrients affecting plant growth on acidic soil profiles from an old pasture

1986 ◽  
Vol 26 (6) ◽  
pp. 681 ◽  
Author(s):  
A Pinkerton ◽  
JR Simpson
Keyword(s):  
Subsurface Layer ◽  
Acid Soils ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Soil Profiles ◽  
Poor Growth ◽  
South Wales ◽  
Reconstituted Soil ◽  
Subsurface Layers ◽  
Surface Drying

Previous studies on soils from old pastures in southern New South Wales have demonstrated that nutrients have accumulated at the soil surface, but that the 40-100-mm depth layer in many profiles has become strongly acidic (e.g. pH 4.7), and high in extractable aluminium. Poor growth of subterranean clover has occurred on such soils during dry periods and may be associated with poor root growth in the acidic, nutrient-poor subsurface layers. Possible nutritional causes of these observations were investigated using reconstituted soil profiles. The root and shoot growth of subterranean clover, wheat, oats and lucerne were compared in unamended profiles and in profiles amended by applying nutrients or calcium carbonate (lime) to correct the more obvious deficiencies of the subsurface layers. Subterranean clover grew well as long as the surface soil remained moist, so that plants could utilise the nutrients potentially available within it. When the surface (0-40 mm) was allowed to dry but the subsurface layers remained moist, growth was poor unless phosphate was applied to the moist layer. Subsurface application of lime alone was ineffective. Nitrogen application increased clover growth in the presence of added phosphate or surface moisture, but nitrogen alone did little to alleviate the effects of surface drought. Wheat, and to a lesser extent oats, responded to subsurface lime when the surface was moist, and both responded to subsurface phosphate when the surface was dry. Lucerne responded to subsurface phosphate similarly to subterranean clover but the response was more than doubled in the presence of additional borate and lime. Lime without borate was not effective. When the surface was maintained moist, liming both the surface (0-40 mm) and subsurface layers improved the response over liming the subsurface layer only. The results suggest that declining fertility and productivity in old pastures developed on acid soils may not be rectified by liming alone, but that cultivation, ripping or drilling of phosphate, and in some cases addition of borate, may be required to improve the penetration of nutrients, particularly phosphorus, to greater depth.

Acoustic analysis of an intergrade zone between two call races of the Limnodynastes tasmaniensis complex (Anura : Leptodactylidae) in south-eastern Australia

1975 ◽  
Vol 23 (1) ◽  
pp. 113 ◽  
Author(s):  
MJ Littlejohn ◽  
JD Roberts
Keyword(s):  
Acoustic Analysis ◽  
Secondary Contact ◽  
Ecological Gradient ◽  
North Central ◽  
Call Structure ◽  
Central Victoria ◽  
South Eastern ◽  
Eastern Australia ◽  
Mating Calls ◽  
South Eastern Australia

Mating calls of the northern and southern call races of the L. tasmaniensis complex are described. Analysis of call structure along a transect across the main contact between these allopatric forms in north central Victoria indicates that there is a zone of intergradation between 90 and 135 km wide, about 215 km long and with a north-westerly orientation. The interaction is interpreted as a secondary contact in which there is hybrid or recombinant superiority along a subtle ecological gradient.

scholarly journals First Report of Mucor spp. Causing Root Rot of Radix pseudstellariae in Guizhou Province of China

Plant Disease ◽  
2020 ◽  
Author(s):  
Hongmiao Wu ◽  
Jiachun Wu ◽  
Feng Li ◽  
Ling Zheng ◽  
Jingkai Fan ◽  
...  
Keyword(s):  
Root Rot ◽  
Disease Incidence ◽  
Acid Soils ◽  
Its Region ◽  
Significant Loss ◽  
Day Length ◽  
Guizhou Province ◽  
First Report ◽  
Chinese Medicinal Plants ◽  
Branched Chains

Radix pseudostellariae L. is one of the most common and highly-prized Chinese medicinal plants with various pharmacological effects, and mainly produced in acid soils in the Guizhou and Fujian provinces of southwestern and southeastern China, respectively (Wu et al. 2020). However, consecutive monoculture of R. pseudostellariae results in severe root rot and decline in biomass and quality of underground tubers. Root tubers of R. pseudostellariae are typically planted in December and harvested in next June. Root rot commonly starts developing in May. The disease incidence of root rot was ranging from 37 to 46% in root portions and basal stem of R. pseudostellariae under the consecutive monoculture fields in Shibing County, Guizhou Province, China (108°12ʹE, 27°03ʹN) (Li et al. 2017). Severe root rot was observed in Shibing County in May 2018. Infected plants displayed curly, withered, and yellow leaves, blight, retarded growth, root rot, and yield losses. Abundant whitish mycelia were observed on roots and surrounding soil. Two fungal isolates, designated GZ20190123 and GZ20190124, were obtained from symptomatic roots cultured on potato dextrose agar (PDA). The optimum temperature range for growth of the two isolates was 25 to 30°C. The optimum pH range for the growth of GZ20190123 was 5 to 5.5, whereas GZ20190124 grew better between pH 5 to 8.5. The mean mycelial growth rates of GZ20190123 and GZ20190124 at 30°C were 2.1 and 1.5 cm/day, respectively. Conidia of the two isolates were ovoid or obclavate and were produced in single or branched chains. The internal transcribed spacer (ITS) region was amplified with primers ITS1 and ITS4 (White et al. 1990). The sequences were deposited in GenBank as accession No. MN726736 for GZ20190123 and MN726738 for GZ20190124. Sequence comparison revealed 99% (GZ20190123) and 97% (GZ20190124) identity with previously reported isolate xsd08071 of Mucor racemosus Bull. (accession No. FJ582639.1) and isolate BM3 of Mucor fragilis Bainier (accession No. MK910058.1), respectively, which was confirmed by phylogenetic analysis. The two isolates were tested for pathogenicity on R. pseudostellariae. Six roots of R. pseudostellariae were surface-sterilized with 75% ethanol and stab inoculated with mycelia using a sterile toothpick for each isolate. Sterile distilled water was stab inoculated to twelve roots to serve as the control. Treated roots were incubated in a greenhouse with 16 h day length [light intensity 146.5 μmol/(m2·s)] and day/night temperature 26°C/18°C. The inoculated roots showed the expected symptoms on roots and sprouts 7 days after inoculation, whereas the control roots with sprouts did not show any symptom. The fungi were re-isolated from the diseased roots and confirmed as expected M. racemosus or M. fragilis based on the ITS sequences, which satisfied Koch’s postulates. Thus, isolate GZ20190123 was identified as M. racemosus and GZ20190124 as M. fragilis. Previously, M. racemosus and M. fragilis have been reported as a pathogen on tomato (Kwon and Hong 2005) and grape (Ghuffar et al. 2018), respectively. To our knowledge, this is the first report of M. racemosus and M. fragilis causing root rot of R. pseudostellariae in southwestern China, where the disease could cause a significant loss to production of this important medicinal plant.

scholarly journals Distribution of aluminium among its mobilizable forms in soils of the Jizera Mountains region

2011 ◽  
Vol 50 (No. 8) ◽  
pp. 346-351 ◽  
Author(s):  
L. Mládková ◽  
L. Borůvka ◽  
O. Drábek
Keyword(s):  
Factor Analysis ◽  
Acid Soils ◽  
Total Content ◽  
Soil Characteristics ◽  
Soil Reaction ◽  
Icp Oes ◽  
Soil Factors ◽  
Potential Toxicity

Labile Al forms can be dangerous in acid soils due to their potential toxicity to plants. This paper deals with the distribution of exchangeable, weakly organically bound, and total organically bound Al forms in soils on 98 sites of the Jizera Mountains region. For the extraction of these Al forms, 0.5M KCl (Al<sub>KCl</sub>), 0.3M CuCl<sub>2</sub> (Al<sub>CuCl2</sub>), and 0.05M&nbsp;Na<sub>4</sub>P<sub>2</sub>O<sub>7</sub> (Al<sub>Na4P2O7</sub>) solutions were used, respectively. Aluminium concentrations in all extracts were determined by means of ICP-OES. Following mean concentrations of Al forms were found in the O and B horizons (mg/kg): Al<sub>KCl</sub> &ndash; 1236 and 832, Al<sub>CuCl2</sub>&nbsp;&ndash; 4268 and 1945, and Al<sub>Na4P2O7</sub>&nbsp;&ndash; 5043 and 8420. Basic soil characteristics were determined by commonly used methods. Their influence on Al forms distribution was assessed. Factor analysis showed that the most important soil factors controlling Al forms distribution were soil reaction and the total content of Ca (or Ca and Mg in the B horizon).

Limestone Pelleting of Subterranean Clover Tested on Acid Soils

1959 ◽  
Vol 12 (4) ◽  
pp. 205 ◽  
Author(s):  
William A. Williams ◽  
Burgess L. Kay
Keyword(s):  
Acid Soils ◽  
Subterranean Clover
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