SURVIVAL OF SINGLE-BASIDIOSPORE ISOLATES OF RHIZOCTONIA PRATICOLA AND RHIZOCTONIA SOLANI

1964 ◽  
Vol 10 (5) ◽  
pp. 739-746 ◽  
Author(s):  
George C. Papavizas
Keyword(s):  
Organic Matter ◽  
Rhizoctonia Solani ◽  
High Tolerance ◽  
Single Spore ◽  
Time Rate ◽  
Unamended Soil ◽  
Parent Culture ◽  
Oat Straw ◽  
Rhizoctonia Praticola ◽  
Rate Of Decline

Twenty randomly selected single-basidiospore isolates from each of Rhizoctonia praticola and R. solani differed considerably in their tolerance to CO2, competitive saprophytic activity, and ability to survive within precolonized substrate segments incubated in soils with or without pentachloronitrobenzene (PCNB) or oat straw. With a few exceptions, isolates possessing high saprophytic activity also possessed high tolerance to CO2 and high surviving ability in precolonized substrate. Several single-spore isolates of R. solani possessed higher ability for saprophytic survival in organic matter and lower CO2-sensitivity than their parent culture. Survival of single-basidiospore isolates in precolonized substrate segments was greater in unamended soil or soil amended with oat straw than in soil treated with PCNB. Mature oat straw reduced surviving ability of several isolates, whereas it increased surviving ability of others above that observed in unamended soil. The isolates whose surviving ability was increased by oat straw were mostly those possessing high saprophytic activity in unamended soil. Saprophytic activity and virulence of all isolates tested declined with time. Rate of decline of virulence was much more rapid for weak than strong saprophytes.

Effect of starch on the utilization by sheep of a straw diet supplemented with urea and minerals

1976 ◽  
Vol 27 (1) ◽  
pp. 139 ◽  
Author(s):  
JG Mulholland ◽  
JB Coombe ◽  
WR McManus
Keyword(s):  
Organic Matter ◽  
Nitrogen Retention ◽  
Nitrogen Excretion ◽  
Digestible Organic Matter ◽  
Cellulose Digestibility ◽  
Oat Straw ◽  
Total Body ◽  
Body Energy ◽  
Urinary Nitrogen Excretion ◽  
Urinary Nitrogen

Individually penned Border Leicester x Merino wethers, aged 11 months, were fed ad lib. for 16 weeks on a basal ration of ground, pelleted oat straw, urea and minerals, supplemented with 0, 5, 10, 15, 20, 30 or 40% starch. The diets contained equal percentages of nitrogen and minerals. Dry matter intake reached a maximum of 2000 g/day with 30% starch; above this starch level, digestive disturbances were observed. Organic matter digestibility was increased by the addition of starch, but cellulose digestibility was depressed by as much as 18 units with the addition of 30% starch. Up to 10% the starch level had little effect on cellulose digestibility. Liveweight change was significantly correlated with digestible organic matter intake, mean daily weight gains varying from 22 g with no starch to 104 g with 30% starch. However, a large percentage of the liveweight gain was as total body water, and body energy storage increased appreciably only when the diet contained at least 20% starch. The inclusion of 5% starch slightly depressed both intake and liveweight gain. Daily clean wool production was significantly increased at starch levels higher than 20% and ranged from 5.3 to 7.5 g/day with 0 and 40% starch respectively. Increasing levels of starch had little effect on apparent nitrogen digestibility, but resulted in a substantial increase in nitrogen retention through a reduction in urinary nitrogen excretion. Serum urea levels fell from a mean of 42 mg/100 ml during the first week to 31 mg/100 ml during subsequent periods, with no significant differences between diets. With the general exception of potassium, mineral balances were positive or close to zero throughout the experiment.

Soil and cotton responses to tillage and ameliorant treatments in a brown clay soil. 1. Soil responses and water use

1970 ◽  
Vol 10 (44) ◽  
pp. 313 ◽  
Author(s):  
J Loveday ◽  
JE Saunt ◽  
PM Fleming ◽  
WA Muirhead
Keyword(s):  
Organic Matter ◽  
Water Use ◽  
Clay Soil ◽  
Aggregate Stability ◽  
Surface Layers ◽  
Peak Period ◽  
Relative Water ◽  
Rate Of Decline ◽  
The Hill ◽  
Soil Responses

Furrow-irrigated cotton was grown for two seasons on a previously uncultivated dense clay soil to which the following treatments had been applied :--normal ploughing (18 cm), precision ripping (30 cm), deep ploughing (40 cm), deep ripping (60 cm), and deep ploughing and deep ripping combined, with and without applications of gypsum at 10 tons an acre or organic matter at 2 1/2 tons an acre. The deep tillage significantly increased the porosity of the subsoil, but this extra porosity had largely been lost by the end of the second season. Neither the gypsum nor the organic matter addition had a significant effect upon its rate of decline. Despite the effect on porosity the deep tillages had only small and mostly non-significant effects upon water increment at irrigation. The gypsum treatment, but not the organic matter, increased water entry to the subsoil at irrigation, and this W-as apparently a result of improved hydraulic conductivity and aggregate stability, particularly in the surface layers. Considerable leaching of chloride occurred from the 30-60 cm subsoil zone in both gypsum treated and deep-tilled plots, but not in organic matter plots, and an accumulation of chloride occurred in the 0-10 cm layer (the hill) in gypsum treated plots. The increased water intake to the subsoil resulting from gypsum treatment was matched by increased water use in the following period, and hence a reduction in relative water deficit of Leaves during the peak period of water demand. Neither the organic matter nor the deep tillages had appreciable influence on water uptake. Water use during periods of peak demand was about 6 mm a day for gypsum treated plots, and this was probably lower than mould have been obtained with water freely available at all times. On the other treatments it can he inferred that water use was even further reduced by lack of available water.

SYNTHESIS OF HETEROKARYONS IN RHIZOCTONIA SOLANI KÜHN

1963 ◽  
Vol 41 (6) ◽  
pp. 879-886 ◽  
Author(s):  
H. S. Whitney ◽  
J. R. Parmeter Jr.
Keyword(s):  
Rhizoctonia Solani ◽  
Single Spore ◽  
Wide Range ◽  
Cultural Types

The single-spore progeny of an isolate of Rhizoctonia solani showed a wide range of cultural types. When these progeny were paired by plating on opposite sides of Petri plates or by mixing semiliquid cultures, certain combinations gave rise to heterokaryons. The heterokaryons originated from hyphal anastomoses and were culturally distinct from either of the contributing homokaryons. Observations suggested a bipolar coaipatibility mechanism among the homokaryons. Some homokaryotic strains fruited, yielding culturally indistinguishable progeny. These homothallic lines also formed heterokaryons with other homothallic lines. The progeny of these heterokaryons showed a wide range of cultural types, indicating that some homokaryons could fruit either homothallically or heterothallically.

The effect of barley supplements on the voluntary intake and digestion of low quality roughages by sheep

1979 ◽  
Vol 92 (1) ◽  
pp. 235-241 ◽  
Author(s):  
C. S. Lamb ◽  
J. Eadie
Keyword(s):  
Organic Matter ◽  
Volatile Fatty Acid ◽  
Latin Square ◽  
Molar Proportion ◽  
Rumen Ph ◽  
Volatile Fatty Acid Concentration ◽  
Acid Detergent Fibre ◽  
Oat Straw ◽  
Ad Libitum ◽  
Voluntary Intake

SummaryOat straw, timothy straw and two field-cured hays (43·8, 47·3, 52·0 and 56·0% organic matter digestibility (OMD) and 0·56, 0·75, 1·00 and 1·41% N respectively) were fed ad libitum together with 0, 235, 470 and 705 g D.M. of rolled barley to 5-year-old North Country Cheviot wethers in four 4x4 Latin square designs (Expt 1). In an attendant study (Expt 2) of conditions with in the rumen four rumen fistulated wethers were offered daily 0, 200, 400 and 600 g D.M. of rolled barley with ad libitum hay (54·3% OMD, 1·45% N), also following a Latin square design.The voluntary intake of two of the hays (54·3 and 56·0% OMD) decreased progressively as the barley increased. Intakes of the other roughages were slightly increased when the lowest amount of barley was fed. For each roughage total organic-matter intake and the OMD of the ration increased progressively with increasing amount of barley consumed. No associative effects of barley on the OMD of the roughages were demonstrated. The acid-detergent fibre (ADF) digestibility of diets comprising the highest amount of barley with the oat straw and the field-cured hay of lowest N content were significantly lower than that of the respective all-roughage feeds. In Expt 2 the intake of increasing amounts of barley significantly reduced rumen pH, the molar proportion of acetic acid and the disappearance of hay and hay ADF from terylene bags within the rumen, while volatile fatty acid concentration and the molar proportion of butyric acid increased.Multiple regressions were obtained relating the change in roughage intake to the amount of barley fed and the digestibility and chemical composition of the roughages. The equation with the least error, explaining 88% of the variation, was Y= 30·561 — 0·615C — 21·453N±3·69, where Y is the change in roughage intake as a percentage of the intake of roughage fed alone, Cis barley intake as g OM/W0·73 and N is the nitrogen content of the roughage.

The effect of urea on the utilization of ground, pelleted roughage by penned sheep: II. Utilization of organic matter, nitrogen and minerals

1969 ◽  
Vol 72 (2) ◽  
pp. 261-269 ◽  
Author(s):  
J. B. Coombe ◽  
K. R. Christian
Keyword(s):  
Organic Matter ◽  
Water Intake ◽  
Salt Intake ◽  
Total Output ◽  
Mineral Supplement ◽  
Phosphorus Balance ◽  
Mineral Supplementation ◽  
Oat Straw ◽  
The Difference ◽  
N Status

SUMMARYAdult Merino wethers were fed for 16 weeks on diets of oat straw mixed with urea and pelleted (A); oat straw pellets, with access to a salt block (B); oat straw pellets, with access to a salt-urea block (C); Phalaris straw mixed with urea and pelleted (D); and Phalaris straw pellets (E). A commercial mineral supplement was given during the first 8 weeks, and a laboratory-prepared complete mineral supplement supplied during the second 8 weeks. During the fifth to eighth weeks (period I), and the thirteenth to sixteenth weeks (period II), digestibility and balance studies were conducted on sheep from each treatment.Digestibilities of organic matter (O.M.) and cellulose were generally increased by the addition of urea, but only in one comparison, between diets A and B, was the difference significant. Urea did not significantly affect water intake in relation to food intake.Urea increased nitrogen (N) intake, faecal and urinary N excretion, and N balance, these effects being more pronounced in period II. All sheep were in negative N status in period I; five of the 12 urea-fed sheep were in positive N status in period II. In diets B and C water intake and urine output were positively related to salt intake, but in no diet was there a significant relation between urinary N excretion and total output of urine.Sulphur balances (excluding wool) were generally positive and did not improve significantly in period II despite higher sulphur intakes. However, a corresponding increase in the intake of phosphorus, from 0·5 g/day to about 2·0 g/day, brought nearly all sheep from negative to positive phosphorus balance. With the urea diets there was a significant, negative relation between urinary N excretion and phosphorus balance.Intakes of sodium, potassium, calcium and magnesium appeared to be sufficient in both periods.It seems likely that the improved response to urea which occurred during the experiment was due to the change in mineral supplementation rather than to adaptation to urea.

Changes occurring in the organic matter during the decomposition of compost heaps

1942 ◽  
Vol 32 (4) ◽  
pp. 360-372 ◽  
Author(s):  
M. R. F. Ashworth
Keyword(s):  
Organic Matter ◽  
Large Scale ◽  
Nutrient Content ◽  
Proximate Analysis ◽  
Water Soluble ◽  
Soluble Nitrogen ◽  
Bulk Materials ◽  
Residual Nitrogen ◽  
Relative Water ◽  
Oat Straw

1. The decomposition of the organic matter of four medium to large-scale composts has been studied by analysis of samples taken at intervals.2. The bulk materials of the composts were grass-cuttings, oat-straw, Sphagnum peat and an Eriophorum and Sphagnum peat. All were made up to the same nutrient-content and relative water content.3. The analytical method used was a modification of the scheme of proximate analysis used by Waksman and by Shewan. It was supplemented by ammonia and nitrate determinations, using Olsen's method.4. Observations.A. All composts.(i) An increase in ammonia, water-soluble nitrogen and water-soluble organic matter took place during the first month.(ii) Only low nitrate concentrations were developed.(iii) Very closely parallel changes in H2SO4-soluble nitrogen and residual nitrogen were recorded.(iv) Other nitrogen changes can be described as slight and on the whole as mutually compensating fluctuations.

Production of aflatoxin by Aspergillus wentii Wehmer

1969 ◽  
Vol 15 (8) ◽  
pp. 895-898 ◽  
Author(s):  
H. W. Schroeder ◽  
M. Jacqueline Verrett
Keyword(s):  
Chick Embryo ◽  
Aflatoxin Production ◽  
Single Spore ◽  
Two Cultures ◽  
Additional Requirement ◽  
Field Corn ◽  
Parent Culture ◽  
Aspergillus Wentii ◽  
Aflatoxin B

Two cultures of Aspergillus wentii isolated from white field corn were tested through three consecutive single-spore generations for the ability to produce aflatoxins. Aflatoxin production by A. wentii was established. Production was low and variable. The variability was apparently not due to inhomogeneity in the parent culture. The identity of aflatoxin B1 was confirmed by chemical derivative tests and by the chick embryo bioassay. The ability to accumulate, as well as to produce, the aflatoxins is suggested as an additional requirement to qualify a fungus as an aflatoxin producer.

EXTRACTABILITY OF NICKEL ADDED TO SOILS AND ITS CONCENTRATION IN PLANTS

1969 ◽  
Vol 49 (3) ◽  
pp. 335-342 ◽  
Author(s):  
R. L. Halstead ◽  
B. J. Finn ◽  
A. J. MacLean
Keyword(s):  
Organic Matter ◽  
Soil Properties ◽  
Organic Matter Content ◽  
Acid Soils ◽  
Matter Content ◽  
Neutral Soil ◽  
Oat Straw

The effect of Ni pretreatments on the yield and concentration of Ni in oats and alfalfa grown in four soils in pot tests varied with the rate of added Ni, with lime and phosphate treatments, and with soil properties, notably pH and organic matter content. The concentrations of Ni in the crops showing repressive effects of added Ni were at least 60 ppm in the oat grain, 28 ppm in the oat straw, and 44 ppm in the alfalfa. The amounts of soil-extractable Ni and the concentrations of Ni in the plants were reduced by liming of the acid soils and they tended to be increased by addition of phosphate. The effects of the Ni pretreatments on growth were less severe in a neutral soil and in one containing considerable organic matter than in the others.

COMPARATIVE EFFECTIVENESS OF SOME ORGANIC AMENDMENTS AND FUNGICIDES IN REDUCING ACTIVITY AND SURVIVAL OF RHIZOCTONIA SOLANI IN SOIL

1962 ◽  
Vol 8 (6) ◽  
pp. 915-922 ◽  
Author(s):  
G. C. Papavizas ◽  
C. B. Davey ◽  
R. S. Woodard
Keyword(s):  
Rhizoctonia Solani ◽  
Active Ingredient ◽  
Comparative Effectiveness ◽  
Organic Amendments ◽  
Cellulose Powder ◽  
N Content ◽  
Fungicidal Action ◽  
Oat Straw ◽  
Reducing Activity

Cellulose powder, oat straw, and soybean hay enriched with NH4NO3 to produce C/N ratios of 60, 30, and 10, respectively, were just as effective as the fungicide PCNB and more effective than the fungicides H 3944 and CP 30249 in reducing the saprophytic activity of Rhizoctonia solani in artificially infested non-sterilized soils 4 weeks after incorporation. One week after incorporation only oat straw and the three fungicides at 50 and 100 p.p.mf. of the active ingredient reduced R. solani activity appreciably. The effectiveness of CP 30249 and PCNB in reducing the saprophytic activity of 5 R. solani clones in soil depended on the fungicide and inoculum concentrations and on the different sensitivities of the clones. Oat straw with C/N ratios of 30 and 80 was more effective in reducing the survival of R. solani in precolonized substrate segments than oat straw with C/N ratio 10 and PCNB at 25 and 50 p.p.m. High decolonizing ability of oat straw with low N content was associated with increased numbers of actinomycetes and bacteria in soil. The sensitivity of R. solani to amendment decomposition and fungicidal action was greater before the fungus saprophytically colonized the substrate than after it became established within the substrate.

PRELIMINARY STUDIES ON THE SEXUAL STAGE OF RHIZOCTONIA SOLANI KÜHN

1953 ◽  
Vol 31 (6) ◽  
pp. 699-710 ◽  
Author(s):  
E. J. Hawn ◽  
T. C. Vanterpool
Keyword(s):  
Rhizoctonia Solani ◽  
Parent Strain ◽  
Sexual Stage ◽  
Diploid Nucleus ◽  
Single Spore ◽  
Perfect Stage ◽  
Rich Media ◽  
Close Relationship ◽  
Germ Tubes ◽  
Growth Characters

The perfect stage of a flax strain of Rhizoctonia solani Kühn was obtained fairly consistently on artificial media. In growth characters and morphological dimensions, it agreed closely with those of Pellicularia filamentosa (Pat.) Rogers, except that its sterigmata averaged three times as long (26 μ). This latter character suggests close relationship to Corticium praticola Kotila. Single-basidiospore cultures differed among themselves and from the parent strain in morphology, cultural characters, growth rates, and pathogenicity on Royal flax. Some single-spore cultures produced the perfect stage, although preliminary pairings of sterile single-spore cultures remained sterile. This isolate is thus heterozygous and homothallic. There appear to be 12 chromosomes in the diploid nucleus in the basidium. The mature basidiospore is predominantly uninucleate; occasionally a binucleate basidiospore is observed. Germination is by repetition on plain agar, or by germ tubes on rich media. Those basidiospores which germinate by repetition are commonly uninucleate and give rise to uninucleate secondary basidiospores. Basidiospore discharge is by the drop excretion mechanism. To determine the identity of the flax strain, it will be necessary to produce the perfect stage of the flax strain on natural substrates or the perfect stage of P. filamentosa on artificial media.

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