Behavior of Phytophthora clandestina propagules at a field site in Western Australia

The number of infective propagules of Phytophthora clandestina, an important pathogen of subterranean clover, was estimated by the most probable number (MPN) method in soil at a field site in Western Australia. The behaviour of the propagules of this fungus was studied in relation to root disease index (RDI), disease suppressiveness index (DSI), rainfall, soil moisture and soil temperature for a period of 12 months. There was an increase in the number of infective propagules in the field soil in January and no further increase was observed until May, then marked decrease occurred in June and July with the numbers remaining low through to December. There was no significant correlation between MPN and RDI, DSI, rainfall, soil moisture or temperature. The RDI was, however, negatively correlated (P < 0.05) with DSI linearly (r = 0.76) and quadratically (r = 0.81). Subterranean clover appears to be the sole source of P. clandestina inoculum in the pasture sward of mixed plant species.

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Diversity and symbiotic effectiveness of Rhizobium leguminosarum bv. trifolii isolates from pasture soils in south-western Australia

Soil Research ◽

10.1071/sr01052 ◽

2002 ◽

Vol 40 (8) ◽

pp. 1319 ◽

Cited By ~ 13

Author(s):

M. T. Collins ◽

J. E. Thies ◽

L. K. Abbott

Keyword(s):

Western Australia ◽

Rhizobium Leguminosarum ◽

Subterranean Clover ◽

Most Probable Number ◽

Enzyme Linked Immunosorbent Assay ◽

Symbiotic Effectiveness ◽

Probable Number ◽

Pcr Fingerprinting ◽

Rapd Pcr ◽

Inoculant Strain

The abundance of the Australian inoculant strain of Rhizobium leguminosarum bv. trifolii for subterraneum clover (WU95) and the diversity of naturalised rhizobia were assessed in 3 subterranean clover pastures in the Albany region of south-western Western Australia. Most probable number, enzyme linked immunosorbent assay (ELISA), and polymerase chain reaction (PCR) techniques were used. A putative strain similar to inoculant strain WU96 was uncommon at one site (South Stirling) and not isolated at 2 other sites. Randomly amplified polymorphic DNA (RAPD) PCR fingerprinting using the RPO1 primer identified 45 different profiles amongst the 208 isolates examined. RAPD-PCR fingerprinting using the primers RPO4 and RPO5 confirmed most groupings based on RPO1 fingerprint patterns and revealed further genetic diversity within some groups. Overall, 54 putative strains were defined by RAPD-PCR fingerprint profiles across the 3 sites. Subterranean clover rhizobia at the Manypeaks and Mount Shadforth sites were dominated by isolates with 1 or 2 RPO1 RAPD profiles at 2 sampling times, while the population at South Stirling was much more diverse. The symbiotic effectiveness of 11 rhizobial isolates, representing the major RPO1 RAPD profile groups within naturalised rhizobial populations, were compared in pot culture with those of the 2 commercial inoculant strains for subterranean clover, WU95 and TA1, on 3 cultivars. Differences in effectiveness among 3 of the 11 isolates were observed in comparison to both the commercial strains and other naturalised isolates. The nitrogen fixing effectiveness of 8 isolates representing different subgroups from one RP01 group was not the same. The use of all 3 primers increased the precision in defining putative strains of Rhizobium leguminosarum bv. trifolii, and although naturalised rhizobia from these pastures are saprophytically competent, their dominance in nodules does not appear to be linked to symbiotic effectiveness.

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Effects of Monoculture, Crop Rotation, and Soil Moisture Content on Selected Soil Physicochemical and Microbial Parameters in Wheat Fields

Applied and Environmental Soil Science ◽

10.1155/2012/593623 ◽

2012 ◽

Vol 2012 ◽

pp. 1-13 ◽

Cited By ~ 7

Author(s):

A. Marais ◽

M. Hardy ◽

M. Booyse ◽

A. Botha

Keyword(s):

Soil Moisture ◽

Microbial Communities ◽

Crop Rotation ◽

Management Practices ◽

Agricultural Soils ◽

Soil Microbial Communities ◽

Soil Microbial Activity ◽

Most Probable Number ◽

Probable Number ◽

Soil Microbial

Different plants are known to have different soil microbial communities associated with them. Agricultural management practices such as fertiliser and pesticide addition, crop rotation, and grazing animals can lead to different microbial communities in the associated agricultural soils. Soil dilution plates, most-probable-number (MPN), community level physiological profiling (CLPP), and buried slide technique as well as some measured soil physicochemical parameters were used to determine changes during the growing season in the ecosystem profile in wheat fields subjected to wheat monoculture or wheat in annual rotation with medic/clover pasture. Statistical analyses showed that soil moisture had an over-riding effect on seasonal fluctuations in soil physicochemical and microbial populations. While within season soil microbial activity could be differentiated between wheat fields under rotational and monoculture management, these differences were not significant.

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Seed production from three annual species of Trifolium on sandy soils in the wheat belt of Western Australia

Australian Journal of Experimental Agriculture ◽

10.1071/ea9690092 ◽

1969 ◽

Vol 9 (36) ◽

pp. 92 ◽

Cited By ~ 2

Author(s):

GB Taylor ◽

RC Rossiter

Keyword(s):

Soil Moisture ◽

Seed Production ◽

Western Australia ◽

Plant Density ◽

Subterranean Clover ◽

Soil Conditions ◽

Seeding Rate ◽

Relative Water ◽

Plant Densities ◽

Seed Yields

Seed production and persistence of subterranean, cupped, and rose clovers were examined over a period of three years in undefoliated swards, at several plant densities, in the wheat belt of Western Australia. Subterranean clover, although earlier flowering, was outyielded by the other two species in the two driest years. No major differences were found between species in relative water content of leaves during periods of soil moisture deficit. Moreover, species differences in soil moisture exploitation were small. A high proportion of inflorescences failed to set seed in subterranean clover. This reproductive defect, which is associated with restricted inflorescence burial due to dry soil conditions, was thought to be the main reason for the poorer seed yield in this species. Despite low seed yields in the establishment year, plant density after the first year did not seriously limit seed yields, even at the lowest seeding rate, in any of the three species.

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Correlations Between Most Probable Number and Activity of Nematode-Trapping Fungi

Phytopathology ◽

10.1094/phyto.2003.93.12.1599 ◽

2003 ◽

Vol 93 (12) ◽

pp. 1599-1605 ◽

Cited By ~ 21

Author(s):

B. A. Jaffee

Keyword(s):

Population Density ◽

Most Probable Number ◽

Field Soil ◽

Arthrobotrys Oligospora ◽

Probable Number ◽

Pvc Pipe

Soil cages were used to determine whether nematode-trapping fungi population density, as measured by most probable number (MPN) procedures, was correlated with the trapping of nematodes. Fungi studied (and trap type) were Arthrobotrys oligospora (adhesive networks), A. eudermata (adhesive networks), A. dactyloides (constricting rings), Dactylellina ellipsospora (adhesive knobs), and D. haptotyla (adhesive knobs). The fungi were formulated as assimilative hyphae in dried alginate pellets. Pellets were added to field soil, the soil was packed into 80-cm3 cages (PVC pipe, 3.0 cm long and 3.9 cm in diameter), and the cages were buried in vineyards. After 14 to 61 days, the cages were recovered, and MPN data and trapping activity were determined. For all five fungi, MPN data were correlated with the number of pellets added. Regardless of fungus population density, A. oligospora and A. eudermata trapped few if any nematodes in soil, and consequently, trapping and fungus population density were not correlated. The correlation between population density and trapping was weak for A. dactyloides but relatively strong for D. ellipsospora and D. haptotyla. High levels of trapping by the latter two fungi required more than 102 fungus propagules per gram of soil.

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Symbiotic performance of Mediterranean Trifolium spp. with naturalised soil rhizobia

Crop and Pasture Science ◽

10.1071/cp11047 ◽

2011 ◽

Vol 62 (10) ◽

pp. 903 ◽

Cited By ~ 17

Author(s):

E. A. Drew ◽

N. Charman ◽

R. Dingemanse ◽

E. Hall ◽

R. A. Ballard

Keyword(s):

Dry Matter ◽

Rhizobium Leguminosarum ◽

Subterranean Clover ◽

Trifolium Subterraneum ◽

Most Probable Number ◽

Diverse Populations ◽

Symbiotic Efficiency ◽

Probable Number ◽

Mediterranean Origin ◽

Inoculant Strain

Naturalised soil rhizobia that nodulate clover occur in high number and are known to vary in their symbiotic performance (SP) with subterranean clover (Trifolium subterraneum L.). However, the extent of suboptimal fixation across a range of other clover species is not well understood. T. subterraneum and nine other annual clover species of Mediterranean origin were evaluated for their SP in combination with the naturalised clover rhizobia in 71 Australian soils and five strains of Rhizobium leguminosarum bv. trifolii that have been used in the inoculants produced for clovers. The most probable number method, using subterranean clover as the trap plant was used to estimate the number of clover rhizobia in the soils. Ninety-two percent of soils tested contained more than 1000 rhizobia/g. An extract of each soil, or strain of rhizobia was used to inoculate plants growing in N-deficient media in the greenhouse. Plants were grown for 4 weeks after inoculation and shoot dry matter determined and expressed as a percentage of the ‘best’ soil rhizobia treatment, to provide a proportional measure of SP for each clover species. SP (mean of clover species) ranged from 96% with the current inoculant strain for annual clovers (WSM1325) down to 48% with former inoculant strain WU95. When inoculated with soils predominantly from mainland Australia, SP (mean of soil treatments) of the different Trifolium spp. was 55% (resupinatum), 53–47% (subterraneum), 50% (nigrescens), 49% (michelianum), 48% (isthmocarpum), 38% (hirtum), 35% (purpureum), 32% (vesiculosum), 25% (spumosum) and 21% (glanduliferum). Within each of the clover species, SP resulting from individual soil treatments ranged from 100% (by definition for the best soil treatment) down to close to zero. Trifolium glanduliferum formed nodules readily with the inoculant strains but nodulation was erratic with the rhizobia in many soils. It is therefore proposed that the naturalised rhizobia in many soils are unlikely to be inoculant strains. This research demonstrates symbiotic efficiency across annual clover species is compromised where diverse populations of clover rhizobia have naturalised in soils.

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Analysis of Coliform and Colifecal Total Pollution Test on Various Types of Drinking Water Using the MPN (Most Probable Number) Method

Serambi Journal of Agricultural Technology ◽

10.32672/sjat.v2i2.2416 ◽

2020 ◽

Vol 2 (2) ◽

Author(s):

Wanda Aulya ◽

Fadhliani Fadhliani ◽

Vivi Mardina

Keyword(s):

Drinking Water ◽

Fecal Coliform ◽

Pathogenic Bacteria ◽

Microbiological Quality ◽

Coliform Bacteria ◽

Most Probable Number ◽

Inspection Method ◽

Sample Number ◽

Probable Number ◽

Fecal Coliform Bacteria

Water is the main source for life and also the most severe substance caused by pollution. The mandatory parameters for determining microbiological quality of drinking water are total non-fecal Coliform bacteria and Coliform fecal (Escherichia coli). Coliform bacteria are a group of microorganisms commonly used as indicators, where these bacteria can be a signal to determine whether a water source has been contaminated by bacteria or not, while fecal Coliform bacteria are indicator bacteria polluting pathogenic bacteria originating from human feces and warm-blooded animals (mammals) . The water inspection method in this study uses the MPN (Most Probable Number) method which consists of 3 tests, namely, the presumption test, the affirmation test, and the reinforcement test. The results showed that of 15 drinking water samples 8 samples were tested positive for Coliform bacteria with the highest total bacterial value of sample number 1, 15 (210/100 ml), while 7 other samples were negative. From 8 positive Coliform samples only 1 sample was stated to be negative fecal Coliform bacteria and 7 other samples were positive for Coliform fecal bacteria with the highest total bacterial value of sample number 1 (210/100 ml).

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Cemaran Eshericia coli dalam makanan laut yang beredar di pasar tradisional Kota Pontian

Jurnal Kesehatan Khatulistiwa ◽

10.26418/jurkeswa.v1i1.42974 ◽

2015 ◽

Vol 1 (1) ◽

pp. 44

Author(s):

Rafika Sari ◽

Pratiwi Apridamayanti

Keyword(s):

Most Probable Number ◽

Probable Number

Latar Belakang: Makanan laut merupakan salah satu jenis makanan yang banyak dikonsumsi oleh masyarakat selain sebagai komoditi ekspor. Mengkonsumsi makanan laut yang telah terkontaminasi bakteri hidup atau toksin yang dihasilkannya dapat menyebabkan keracunan makanan. Tujuan penelitian ini adalah untuk mengetahui adanya kontaminasi bakteri koliform E.coli sebagai indikator pencemaran pada makanan laut dan memberikan informasi kelayakan dan keamanan konsumsi dari makanan laut di dua pasar tradisional terbesar di daerah Pontianak. Metode: Sampel yang digunakan adalah ikan, sotong dan udang. Penelitian terhadap sampel dilakukan menggunakan uji Most Probable Number (MPN) yang dilengkapi dengan uji biokimia untuk mengidentifikasi jenis bakteri pada sampel melalui penanaman bakteri pada media agar Lactose Broth (LB) dan Briliant Green Lactose Bile Broth (BGLB). Hasil: Hasil penelitian menunjukkan bakteri koliform E.coli terdeteksi pada 100% sampel dengan nilai MPN yang tidak memenuhi kriteria kelayakan konsumsi, yakni >3/g. Kesimpulan: Makanan yang ada tidak memenuhi kriteria kelayakan konsumsi.

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