A study of factors influencing the genetics of reaction of barley to root rot caused by Helminthosporium sativum

1969 ◽  
Vol 47 (3) ◽  
pp. 429-443 ◽  
Author(s):  
E. Cohen ◽  
S. B. Helgason ◽  
W. C. McDonald
Keyword(s):  
Root Rot ◽  
Seed Weight ◽  
Field Resistance ◽  
Controlled Environment ◽  
Drastic Reduction ◽  
Similar Nature ◽  
High Positive Correlation ◽  
Polygenic Inheritance ◽  
Helminthosporium Sativum ◽  
Made In

The inheritance of seedling reaction to root rot, caused by the 514 isolate of Helminthosporium sativum, was studied in crosses and backcrosses among the barley varieties CI.8969 and CI.8873, which show resistance, and the variety Olli, which is susceptible. The study was carried out under a controlled environment in growth cabinets. The data from reaction tests of F3 and backcross families were analyzed by Elston's procedure for testing a one-locus hypothesis, and by Powers' partitioning method. Polygenic inheritance for seedling reaction was indicated, but subsequent experiments showed that seed weight strongly influenced the reaction, which could account for the polygenic interpretation. Based on a drastic reduction of resistance in greenhouse-produced seed, irrespective of seed weight, a high positive correlation of seed weight with resistance in field-produced seed, and other evidence of a similar nature, it was assumed that resistance was related to a principle, present in the seed or on the seed surface, the quantity of which was influenced by seed size and modified by environment. Whether there was a genotypic influence on the quantity of the resistance principle, aside from that affecting seed weight, was not established conclusively. A field study involving the same materials, made in an area known to produce natural root-rot infection, showed that no correlation existed between the disease indices of the entries in the seedling stage in the growth-cabinet tests, and their reaction to the disease in the field. CI.8873 showed field resistance, whereas CI.8969 did not.

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.

Factors contributing to poor lucerne persistence in southern Queensland

1977 ◽  
Vol 17 (89) ◽  
pp. 998 ◽  
Author(s):  
JAG Irwin
Keyword(s):  
Bacterial Wilt ◽  
Root Rot ◽  
Crown Rot ◽  
Wide Spread ◽  
Phytophthora Megasperma ◽  
Phytophthora Root Rot ◽  
Colletotrichum Trifolii ◽  
Disease Survey ◽  
Disease Surveys ◽  
Made In

Lucerne disease surveys made in southern Queensland have shown the presence of seven fungal root and crown diseases. The two most wide spread and serious diseases are Phytophthora root rot (Phytophthora megasperma) and Colletotrichum crown rot (Colletotrichum trifolii). The general disease survey did not reveal the presence of bacterial wilt (Corynebacterium insidiosum) in Queensland. Studies made on the survival of lucerne populations for 2.5 years at three sites in Queensland have shown that disease was the major cause of all detected plant deaths.

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 THE CONTROL OF ROOT-ROT DISEASES OF CEREALS: IV. INFLUENCE OF MECHANICAL SEED INJURY ON INFECTION BY FUSARIUM CULMORUM IN WHEAT

1936 ◽  
Vol 14c (12) ◽  
pp. 438-444 ◽  
Author(s):  
J. E. Machacek ◽  
F. J. Greaney
Keyword(s):  
Root Rot ◽  
Field Experiments ◽  
Fusarium Culmorum ◽  
Western Canada ◽  
Wheat Seed ◽  
Fusarium Root Rot ◽  
Field Plots ◽  
Made In ◽  
Experimentally Induced

The results of field experiments made in 1932, 1933, and 1934, to determine the effect of mechanical seed injury on the incidence of root rot caused by Fusarium culmorum and on yield in wheat are presented.Successful positive attacks of Fusarium root rot were experimentally induced in field plots. The tests showed that reduced emergence, increased root rot, and reduced yield uniformly followed the planting of injured wheat seed; and that the amount of disease increased and the yield decreased with an increase in the degree of seed injury. In these experiments Mindum and Marquis wheat seemed equally affected by seed injury.The investigation suggests that the large annual losses in yield caused by root-rot diseases of cereals in Western Canada may be substantially reduced by sowing clean, vigorous, sound seed.

Role of toxins in etiology of root rot disease of wheat

1977 ◽  
Vol 55 (13) ◽  
pp. 1801-1806 ◽  
Author(s):  
Ross B. Pringle
Keyword(s):  
Root Rot ◽  
Toxic Substance ◽  
Toxic Metabolite ◽  
Root Rot Disease ◽  
Culture Filtrates ◽  
Helminthosporium Sativum ◽  
Rot Disease

Although no host-specific toxin, nor a great quantity of any toxic substance, has been found in culture filtrates of 26 different isolates of Helminthosporium sativum, the amount of the toxic metabolite, victoxinine, produced by these strains, may be correlated generally to their aggressiveness towards wheat.

scholarly journals Effect of Clay Mineralogy on Iron Bioavailability and Rhizosphere Transcription of 2,4-Diacetylphloroglucinol Biosynthetic Genes in Biocontrol Pseudomonas protegens

2013 ◽  
Vol 26 (5) ◽  
pp. 566-574 ◽  
Author(s):  
Juliana Almario ◽  
Claire Prigent-Combaret ◽  
Daniel Muller ◽  
Yvan Moënne-Loccoz
Keyword(s):  
Root Rot ◽  
Molecular Mechanisms ◽  
Clay Mineralogy ◽  
Iron Bioavailability ◽  
Thielaviopsis Basicola ◽  
Synthetic Genes ◽  
Rot Disease ◽  
Number Of Cells ◽  
Made In

Pseudomonas strains producing 2,4-diacetylphloroglucinol (DAPG) can protect plants from soilborne phytopathogens and are considered the primary reason for suppressiveness of morainic Swiss soils to Thielaviopsis basicola-mediated black root-rot disease of tobacco, even though they also occur nearby in conducive sandstone soils. The underlying molecular mechanisms accounting for this discrepancy are not understood. In this study, we assessed the hypothesis that the presence of iron-rich vermiculite clay (dominant in suppressive soils) instead of illite (dominant in neighboring conducive soils) translates into higher levels of iron bioavailability and transcription of Pseudomonas DAPG synthetic genes in the tobacco rhizosphere. Rhizosphere monitoring of reporter gene systems pvd-inaZ and phlA-gfp in Pseudomonas protegens indicated that the level of iron bioavailability and the number of cells expressing phl genes (DAPG synthesis), respectively, were higher in vermiculitic than in illitic artificial soils. This was in accordance with the effect of iron on phlA-gfp expression in vitro and, indeed, iron addition to the illitic soil increased the number of cells expressing phlA-gfp. Similar findings were made in the presence of the pathogen T. basicola. Altogether, results substantiate the hypothesis that iron-releasing minerals may confer disease suppressiveness by modulating iron bioavailability in the rhizosphere and expression of biocontrol-relevant genes in antagonistic P. protegens.

scholarly journals Temperature and Irradiance Effects on Vegetative Growth of Two Species of Leucocoryne

2003 ◽  
Vol 128 (6) ◽  
pp. 815-820
Author(s):  
J.L. Catley
Keyword(s):  
Vegetative Growth ◽  
Low Temperatures ◽  
Controlled Environment ◽  
Plant Parts ◽  
Leaf Emergence ◽  
Mean Temperature ◽  
Made In

The influences of temperature and irradiance on vegetative growth of two species of Leucocoryne (Leucocoryne coquimbensis F. Phil and L. ixioides (Hook.) Lindl.) were examined in controlled environment growth rooms. The growing environments had day/night temperatures of 10/5, 15/10, or 20/15 °C, providing mean temperatures of 7.5, 12.5, or 17.5 °C, and photosynthetic photon fluxes (PPF) of 497 or 710 μmol·m-2·s-1. Leaf emergence data were recorded up to three times a week, and measurements of vegetative growth were made in the rooms twice weekly. Destructive harvests were carried out at intervals up to four weeks apart. Leaves of L. ixioides emerged first in all mean temperatures. As mean temperature decreased from 17.5 to 7.5 °C, the differences in first emergence dates became more apparent between species. Appearance of the second leaf of both species occurred in less than half the number of days the first leaf took to emerge. The time taken for further leaves to develop increased as temperature decreased, particularly for L. ixioides and at mean temperatures below 12.5 °C. Although leaves of L. ixioides emerged first, days to emergence of further leaves increased to lag behind production of L. coquimbensis leaves, particularly when mean temperatures dropped below 12.5 °C. Temperature also significantly affected growth of other plant parts. As mean temperature increased, maximum leaf, root and main bulb dry weights increased for both species, along with secondary bulb dry weights of L. coquimbensis. As irradiance increased, maximum leaf dry weights decreased and maximum bulb dry weights increased of both species, and maximum dropper dry weights of L. coquimbensis increased. Leucocoryne coquimbensis appears to have the greatest capacity to multiply vegetatively and this is enhanced by high mean temperatures. These results suggest that mean temperatures higher than those used in this study are required for sustained leaf emergence, particularly for L. ixioides although this species has the capacity to emerge at low temperatures. High mean temperatures are also likely to promote vegetative mass of all plant parts of both species, whereas higher irradiance levels than used in this study would enhance main bulb growth.

THE USE OF WATER BY WHEAT PLANTS WHEN INOCULATED WITH HELMINTHOSPORIUM SATIVUM

1940 ◽  
Vol 18c (5) ◽  
pp. 178-198 ◽  
Author(s):  
B. J. Sallans
Keyword(s):  
Spring Wheat ◽  
Root Rot ◽  
Marked Reduction ◽  
Dry Matter ◽  
Severely Injured ◽  
Light Conditions ◽  
Water Requirements ◽  
Stages Of Growth ◽  
Early Stages ◽  
Helminthosporium Sativum

The transpirational histories of wheat plants, inoculated with Belminthosporium sativum Param., King & Bakke to produce root rot, showed a marked reduction in water loss during the early stages of growth, when compared with uninoculated plants. This was accompanied by a corresponding reduction in the transpiring areas owing to reduced lengths and widths in the second, third, and fourth leaves to appear. As the plants entered into the early stages of elongation of the culm the transpirational story reflected a recovery in the inoculated plants. The later leaves to appear were longer with greater transpiring areas than in uninoculated plants. This fact combined with the death of the first three or four leaves resulted in greater transpirational and photosynthetic areas in the inoculated plants with consequent increased yields of dry matter. Probably similar recovery does not occur under competitive field conditions, where weeds and healthy wheat plants are present. Poor light conditions and low soil moistures were not conducive to recovery of inoculated plants. The water requirements of wheat did not appear to be affected significantly by inoculation. Of two varieties of spring wheat, Reward was more severely injured initially and recovered more rapidly than Marquis. Several possible explanations of the recovery recorded here are discussed.

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