STUDIES ON FOOT AND ROOT ROT OF WHEAT: VII. SOME FACTORS AFFECTING THE HEALTH OF WHEAT SEEDLINGS IN NUTRIENT SOLUTIONS

1943 ◽  
Vol 21c (1) ◽  
pp. 18-25 ◽  
Author(s):  
L. E. Tyner ◽  
W. C. Broadfoot
Keyword(s):  
Nutrient Solution ◽  
Root Rot ◽  
Fusarium Culmorum ◽  
Hydrogen Ion ◽  
Soil Culture ◽  
Wheat Seedlings ◽  
Factors Affecting ◽  
Ion Concentrations ◽  
Helminthosporium Sativum ◽  
Nutrient Solutions

The effect of iron tartrate on the development of chlorosis in wheat seedlings in nutrient solutions, and also the effect of extracts of Helminthosporium sativum P. K. & B. and Fusarium culmorum W. G. Sm. on disease expression, were studied under greenhouse conditions. Iron tartrate was effective in preventing chlorosis. Less iron was required in summer plantings than in winter plantings. Also, less iron was required in solutions with the higher hydrogen ion concentrations. Under the conditions employed, manganese effected no amelioration of chlorotic symptoms in the presence of a deficiency of iron.Sterilized and unsterilized filtered extracts of the pathogens mentioned added to crocks of the nutrient solution inhibited the growth of wheat seedlings, an effect in soil culture which is interpreted as an index of pathogenicity.

STUDIES ON FOOT- AND ROOT-ROT OF WHEAT: VI. METHODS OF SECURING INFECTION OF WHEAT SEEDLINGS FOR STUDY IN NUTRIENT SOLUTIONS

1938 ◽  
Vol 16c (6) ◽  
pp. 253-261 ◽  
Author(s):  
W. C. Broadfoot ◽  
L. E. Tyner
Keyword(s):  
Nutrient Solution ◽  
Fusarium Culmorum ◽  
Spore Suspension ◽  
Hypodermic Needle ◽  
Culture Solution ◽  
Wheat Seedlings ◽  
Nutrient Culture ◽  
Entire Plant ◽  
Helminthosporium Sativum ◽  
Nutrient Solutions

The two foot-rot diseases of wheat caused by Helminthosporium sativum P. K. & B. and Fusarium culmorum W. G. Sm. were studied in nutrient culture solutions instead of in the usual substrates of soil or sand. The most satisfactory results were obtained by first germinating the grains in a specially designed tray, then securing infection of the young plants by adding inoculum to the tray, after which the seedlings were transplanted to the nutrient culture solution. Infection of the seedlings was distinctly increased when sucrose was added to a nutrient solution infested previous to the time of transplantation. Infection was less satisfactory when the seed was immersed in a spore suspension, dried, and germinated on the tray. Very unsatisfactory infection was secured by adding a spore suspension in water, with or without sugar, to the nutrient solution at the time of transplanting the seedlings. Inoculating the seedlings with a spore suspension by means of a hypodermic needle produced practically no infection. Length of shoot, and particularly the dry and the green weight of the entire plant were reliable quantitative criteria for the evaluation of disease. The first method indicated appears to offer several important advantages in that the degree of infection can be controlled.

ON THE PREVALENCE OF PATHOGENIC FORMS OF HELMINTHOSPORIUM SATIVUM AND FUSARIUM CULMORUM IN THE SOIL OF WHEAT FIELDS AND ITS RELATION TO THE ROOT ROT PROBLEM

1934 ◽  
Vol 10 (3) ◽  
pp. 264-274 ◽  
Author(s):  
G. B. Sanford ◽  
W. C. Broadfoot
Keyword(s):  
Root Rot ◽  
Fusarium Culmorum ◽  
Black Soil ◽  
Seedling Stage ◽  
Infested Soil ◽  
Wheat Seedlings ◽  
Virulent Strains ◽  
Crown Tissue ◽  
Helminthosporium Sativum ◽  
Pot Culture

A total of 227 isolates of Helminthosporium sativum and 286 of Fusarium sp. (culmorum type) were obtained from the diseased crown tissue of wheat stubble in five fields located in the black soil belt of central Alberta, and an attempt was made to determine their relative virulence on wheat seedlings and on mature plants. The experiment was carried out under greenhouse conditions, with a range of soil temperature. Sterilized, artificially infested soil in open pot culture was used. The results indicated that the Helminthosporium isolates were as a rule moderately to weakly pathogenic, and that most of the Fusarium isolates were only weakly pathogenic to wheat plants in the seedling stage. Some isolates of each pathogen exhibited extreme virulence, but judging from the results on seedling plants, virulent strains were rather rare in the fields studied. On mature plants both fungi showed about equal degrees of virulence, which was on the whole weak, and the results were not considered significant for the purpose of the study. More isolates of the greater degrees of virulence were obtained from certain fields than from others. In view of the great susceptibility of seedling plants in sterilized re-infested soil and the variable results, presumably caused by association effects of contaminants of the soil in open pot culture, it was concluded that the object of the study could not be attained by means of data based on the seedling stage, or by the technique employed. The possibility of significant results being secured in sterilized re-infested soil, protected from contamination, and based only on mature plants, is discussed in relation to the root rot problem.

SOME FACTORS AFFECTING THE VIRULENCE OF ARTIFICIAL INOCULUM OF HELMINTHOSPORIUM SATIVUM P. K. AND B. AND OF FUSARIUM CULMORUM (W. G. SM.) SACC.

1941 ◽  
Vol 19c (2) ◽  
pp. 42-48 ◽  
Author(s):  
L. E. Tyner
Keyword(s):  
Fusarium Culmorum ◽  
Corn Meal ◽  
Wheat Seedlings ◽  
Factors Affecting ◽  
Helminthosporium Sativum ◽  
Effect Of Age

Investigations were conducted on the virulence of inoculum of Helminthosporium sativum P. K. and B. and of Fusarium culmorum (W. G. Sm.) Sacc. as affected by the size of the vessel in which the inoculum was increased, the amount of corn meal present in the medium, and the period of incubation. Inoculum of either pathogen containing 12% corn meal caused more disease on wheat seedlings than that with 5%. H. sativum, 14 days old, was more virulent than after 21, 28, or 35 days' incubation, but in the case of F. culmorum, there was no definite tendency with respect to the effect of age. The size of container was unimportant if desiccation was avoided.

STUDIES ON FOOT AND ROOT ROT OF WHEAT: IV. EFFECT OF CROP ROTATION AND CULTURAL PRACTICE ON THE RELATIVE PREVALENCE OF HELMINTHOSPORIUM SATIVUM AND FUSARIUM SPP. AS INDICATED BY ISOLATIONS FROM WHEAT PLANTS

1934 ◽  
Vol 10 (1) ◽  
pp. 115-124 ◽  
Author(s):  
W. C. Broadfoot
Keyword(s):  
Root Rot ◽  
Cultural Practices ◽  
Fusarium Culmorum ◽  
Cultural Practice ◽  
Root Tissue ◽  
Fusarium Spp ◽  
Crown Tissue ◽  
Helminthosporium Sativum ◽  
Relative Prevalence ◽  
Marked Tendency

The crown and root tissue from 43,305 of 47,360 plants examined in this investigation yielded Helminthosporium sativum, Fusarium culmorum and other Fusarium spp., either alone or in combination with these or other fungi and bacteria. It was the exception for any mature plant, the surface tissue of which was disinfected, to be free from fungi or bacteria. None of the various crop sequences or cultural practices used in this study appeared to significantly affect more than another the relative prevalence of either H. sativum or Fusarium spp., as indicated by isolations from the crown tissue of wheat. However, as there was a marked tendency at certain stations each year for H. sativum or Fusarium spp. to predominate, it was concluded that certain factors of the environment were more effective than the crop sequence in modifying the relative prevalence of the two fungi mentioned in the crown and root tissue of wheat plants.

STUDIES ON FOOT AND ROOT ROT OF WHEAT: I. EFFECT OF AGE OF THE WHEAT PLANT UPON THE DEVELOPMENT OF FOOT AND ROOT ROT

1933 ◽  
Vol 8 (5) ◽  
pp. 483-491 ◽  
Author(s):  
W. C. Broadfoot
Keyword(s):  
Root Rot ◽  
Fusarium Culmorum ◽  
Wheat Plant ◽  
Seedling Stage ◽  
Critical Studies ◽  
Helminthosporium Sativum ◽  
Unsterilized Soil ◽  
Micro Organisms ◽  
Effect Of Age ◽  
Made In

Studies were made to determine whether, in sterilized inoculated soil, Marquis wheat plants became more or less susceptible during the post-seedling stage to Ophiobolus graminis, Helminthosporium sativum, and Fusarium culmorum. While it was found that the plants in the seedling stage were more susceptible than at later stages, there was, with the technique used, no evidence that the plants become more or less susceptible during the post-seedling stage. The reasons for indefinite evidence on this important question are given. In sterilized soil, in open pot culture, inoculum of O. graminis was definitely more virulent when alone than when mixed singly or in combination with H. sativum, F. culmorum or Leptosphaeria herpotrichoides. The virulence of all pathogenes mentioned decreased progressively in sterilized soil, the greatest decrease taking place during the first 40 days, after which they were only slightly pathogenic and at the end of 120 days inoculum of O. graminis was impotent. The virulence of inoculum when added to unsterilized soil was greatly reduced in contrast with that in sterilized soil, and after 10 days it was practically at a minimum. These results emphasize the necessity of protecting inoculated sterilized soil against contamination by other micro-organisms in critical studies made in soil. They also throw light on the much recognized difficulty of producing foot rot in the field by prepared inoculum added to such soil.

RELATIVE DECLINE OF OPHIOBOLUS GRAMINIS, HELMINTHOSPORIUM SATIVUM AND FUSARIUM CULMORUM IN THE SOIL

1960 ◽  
Vol 40 (2) ◽  
pp. 288-294 ◽  
Author(s):  
G. Semeniuk ◽  
A. W. Henry
Keyword(s):  
Fusarium Culmorum ◽  
Wheat Crop ◽  
Natural Soil ◽  
Large Measure ◽  
Wheat Seedlings ◽  
Helminthosporium Sativum ◽  
Loam Soil ◽  
Marked Decline ◽  
Relative Decline ◽  
Micro Organisms

The relative decline of three cereal root pathogens, Ophiobolus graminis Sacc., Helminthosporium sativum P. K. B., and Fusarium culmorum (W. G. Sm.) Sacc., in natural and sterilized black loam soil, was studied using inoculum grown in a sterilized soil-cornmeal medium. Since the severity of infection of wheat seedlings by the above fungi proved directly proportional to the amount of inoculum added to natural soil, it was used as a measure of the amount of effective inoculum in the soil at a given time. It was found by this means that inoculum of all three pathogens diminished greatly in amount in natural soil during the first few days following its addition, with that of O. graminis declining least, that of H. sativum more, and that of F. culmorum most. The decline rate was proportional to the amount of inoculum. After one week the decline had progressed further, but it was less for O. graminis than for the other two pathogens. In 3–4 weeks the amount of all three had reached a near-zero quantity. In sterilized soil the decline was similar to that in natural soil after the sterilized soil became recontaminated. However, that of F. culmorum was less pronounced here than in natural soil. Marked decline of O. graminis also occurred in natural soil supporting a seedling wheat crop. In large measure the decline studied appeared to be a quantitative degenerating process resulting from the activity of soil micro-organisms.

STUDIES ON FOOT AND ROOT ROT OF WHEAT: V. THE RELATION OF PHOSPHORUS, POTASSIUM, NITROGEN, AND CALCIUM NUTRITION TO THE FOOT- AND ROOT-ROT DISEASE OF WHEAT CAUSED BY HELMINTHOSPORIUM SATIVUM P. K. & B.

1938 ◽  
Vol 16c (3) ◽  
pp. 125-134
Author(s):  
W. C. Broadfoot ◽  
L. E. Tyner
Keyword(s):  
Nutrient Solution ◽  
Root Rot ◽  
Ionic Concentration ◽  
Foot Rot ◽  
Wheat Grains ◽  
Root Rot Disease ◽  
Helminthosporium Sativum ◽  
Rot Disease ◽  
Aseptic Conditions ◽  
Complete Nutrient Solution

The effect of different amounts of phosphorus, potassium, nitrogen, and calcium upon the development of the foot-rot disease of wheat caused by Helminthosporium sativum P. K. & B. was studied in the greenhouse. The wheat grains were planted in sterilized pure quartz sand to which the necessary nutrients and spore suspension of the pathogen were added. The experiments were maintained under aseptic conditions during the first ten days. The disease increased when the ionic concentration of potassium, nitrogen, and calcium was decreased below that of the complete nutrient solution, but no significant reduction of the disease was observed when the concentrations of all of the elements, including phosphorus, were increased above those in the complete nutrient solution. Apparently extremely small concentrations of phosphorus had no effect on the disease one way or the other. These conclusions apply to the disease on the seedling stage of wheat.

scholarly journals Modeling Nutrient Uptake and Prolonged Use of Nutrient Solutions in Soilless Tomato Culture

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 761F-761
Author(s):  
Mohamed Benmoussa ◽  
Laurent Gauthier
Keyword(s):  
Nutrient Uptake ◽  
Nutrient Solution ◽  
Climatic Factors ◽  
High Yield ◽  
Nutrient Concentrations ◽  
Factors Affecting ◽  
Nutrient Imbalances ◽  
Nutrients Uptake ◽  
Using Data ◽  
Nutrient Solutions

In soilless culture, the buffering capacity of the root environment for nutrients is low. This, combined with fluctuations of climatic factors and changes in nutrient uptake rates, can lead to nutrient imbalances. In order to achieve high yield and better quality, it is necessary to keep the nutrient concentrations in the root environment at the target levels. This requires frequent analysis and adjustments to the nutrient solution. Currently, leaching of the growing media or renewal of the nutrient solution is commonly used to avoid accumulation or depletion of nutrient in the root environment. However, this practice lowers the efficiency of fertilizers and can lead to the contamination of the ground water. One way to remedy to this problem is through the use of nutrients uptake models to track the composition of the nutrient solutions. The objective of this study was to develop such models. Such models can be used to maintain balanced nutrient solutions for longer periods. This can lead to reduced leaching and improved fertilizer use efficiency. Macronutrient (N, P, K, Ca, and Mg) uptake models were developed for tomato plants grown in an NFT system using data collected from experiments conducted in the Laval Univ. greenhouses. Analysis of the experimental results showed that the main factors affecting nutrients uptakes are light and transpiration.

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