Response of Aphanomyces euteiches mycelia, zoospore, and oospore to oat extract

2004 ◽  
Vol 84 (2) ◽  
pp. 687-690
Author(s):  
M. A. Chandler ◽  
V. A. Fritz ◽  
R. R. Allmaras
Keyword(s):  
Pisum Sativum ◽  
Root Rot ◽  
Green Manure ◽  
Mycelial Growth ◽  
Late Summer ◽  
Aphanomyces Euteiches ◽  
Economic Threat ◽  
Pisum Sativum L ◽  
Production Research ◽  
Reduce Disease Severity

Root rot (Aphanomyces euteiches Drechs.) is a serious economic threat to pea (Pisum sativum L.) production. Research has shown a late-summer-seeded oat (Avena sativa L .) crop can reduce disease severity. A. euteiches was exposed to extracts of oat cvs. Bay and Ogle. Oat extract significantly enhanced mycelial growth of the pathogen. Key words: Root rot, biological control, green manure, Pisum sativum

scholarly journals 488 Effect of Oat Extract on Pea Root Rot Pathogen Aphanomyces euteiches

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 529B-529
Author(s):  
M.A. Chandler ◽  
V.A. Fritz ◽  
F.L. Pfleger ◽  
R.R. Allmaras
Keyword(s):  
Spore Germination ◽  
Root Rot ◽  
Mycelial Growth ◽  
Great Lakes Region ◽  
Aphanomyces Euteiches ◽  
Causal Organism ◽  
Economic Threat ◽  
Pea Root ◽  
Germination And Growth ◽  
Pea Root Rot

Pea root rot is a serious economic threat to pea production in the Great Lakes region. The primary causal organism is Aphanomyces euteiches Drechs., which is responsible for an estimated 10% annual crop loss. A fall oat (Avena sativa) rotation before spring pea planting reduces disease severity. To better understand the beneficial effect of oat on A. euteiches, isolated individual pathogen lifecycle stages of zoospores, mycelium, and oospores were treated in culture with oat extract. Resulting mycelial mats were dried and weighed. Treatment with 90%, 70%, 50%, and 30% oat extract resulted in significant spore germination and mycelial growth of A. euteiches. In the presence of nutrient solution, oat extract concentrations of 90%, 70%, 50%, and 30% significantly enhanced spore germination and mycelial growth of the pathogen. These results demonstrate that the use of oat extract results in dosage dependent germination and growth of A. euteiches.

Identification, laboratory, greenhouse and field handling of Aphanomyces euteiches on pea (Pisum sativum L.)

2021 ◽  
Author(s):  
Kimberly Anderson Zitnick ◽  
Lyndon Porter ◽  
Linda E Hanson ◽  
Julie Pasche
Keyword(s):  
Pisum Sativum ◽  
Root Rot ◽  
Lateral Roots ◽  
Infected Plant ◽  
Molecular Techniques ◽  
Economic Losses ◽  
Infested Soil ◽  
Aphanomyces Euteiches ◽  
Pisum Sativum L ◽  
Initial Symptoms

Aphanomyces euteiches is a destructive soilborne plant pathogen, causing economic losses when adequate to excess soil moisture is available. This oomycete organism survives in the soil for decades and infects and degrades roots of plants from 11 families. Symptoms of Aphanomyces root rot are similar across the major economic hosts alfalfa (Medicago sativa subsp. sativa L.), lentil (Lens culinaris Medik.), and pea (Pisum sativum L.). Initial symptoms include the appearance of grey, water-soaked root tissue. Roots develop a golden-brown color, and lateral roots begin to disintegrate as the disease worsens. In the most severe cases, the entire root system is destroyed and aboveground chlorosis and necrosis are observed. A. euteiches isolation can be successful from both infested soil and infected plant tissue. Macroscopically, colony growth is generally nondescript and white in color. A. euteiches is self-fertile (homothallic) and produces sexual oospores in culture in addition to asexual zoosporangia and zoospores (primary and secondary) on hyphae lacking regular septa (coenocytic). Numerous molecular techniques have been developed for successful A. euteiches detection. A. euteiches can be stored in frozen soil or on agar slants, but viability should be evaluated regularly. Oospores or zoospores have been utilized for inoculation under greenhouse and field conditions; although the generation of a field site using soil infestation techniques can take several seasons of productions of a susceptible crop to be utilized to effectively screen for Aphanomyces root rot.

scholarly journals Identification of Pisum sativum Germ Plasm with Resistance to Root Rot Caused by Multiple Strains of Aphanomyces euteiches

Plant Disease ◽  
1999 ◽  
Vol 83 (1) ◽  
pp. 51-54 ◽  
Author(s):  
D. K. Malvick ◽  
J. A. Percich
Keyword(s):  
Pisum Sativum ◽  
Root Rot ◽  
Plant Introduction ◽  
Aphanomyces Euteiches ◽  
Sources Of Resistance ◽  
Breeding Programs ◽  
Pea Seedlings ◽  
Biomass Loss ◽  
Serious Disease ◽  
Multiple Strains

Aphanomyces root rot is a serious disease of pea (Pisum sativum), and additional sources of resistance are needed for development of disease-resistant cultivars. Accessions (n = 123) from the P. sativum Plant Introduction (PI) collection with the highest relative levels of resistance to one strain of Aphanomyces euteiches were previously identified from among approximately 2,500 accessions evaluated. The chosen 123 accessions were evaluated in this study for resistance to root rot caused by multiple strains of this pathogen. Five strains representing different US geographical locations and pathogenicity characteristics were used to evaluate pea seedlings in a greenhouse. Disease severity (DS) and percent loss of fresh biomass (inoculated vs. non-inoculated plants) were determined 15 days after inoculation. Significant differences (P = 0.05) in levels of DS and biomass loss (BL) occurred among the accessions after inoculation individually with the five strains. The relative rank of accessions based on DS and BL varied with the strain of A. euteiches used for inoculations. The 20 accessions with the lowest DS after inoculation with each strain were identified. Based on lowest DS, two accessions were among the 20 identified with all five individual strains, and four other accessions were among the 20 identified with four of the five strains. The results suggest that the P. sativum PI collection contains useful accessions for breeding programs aimed at developing pea varieties with resistance to A. euteiches.

ESTIMATION OF PEA YIELD LOSS FROM SEVERE ROOT ROT AND DROUGHT STRESS USING AERIAL PHOTOGRAPHS AND A LOSS CONVERSION FACTOR

1978 ◽  
Vol 58 (1) ◽  
pp. 159-164 ◽  
Author(s):  
P. K. BASU ◽  
H. R. JACKSON ◽  
V. R. WALLEN
Keyword(s):  
Drought Stress ◽  
Pisum Sativum ◽  
Root Rot ◽  
Yield Loss ◽  
Conversion Factor ◽  
Aerial Photographs ◽  
Average Yield ◽  
Affected Area ◽  
Black And White ◽  
Pisum Sativum L

Vertical aerial photographs were taken over commercial pea (Pisum sativum L.) fields in the Picton-Wellington region, Ontario, in 1975 (a drought year) and in 1976 (a non-drought year) using Kodak Aerochrome Infrared film 2443. Optical separations into black and white images were necessary to assist in delineating healthy crop boundaries from severe root rot- and drought-affected areas (37.14%) as well as void areas (5.29%) from 1975 photographs of 12 selected fields. In these fields, excluding the void areas, an estimated yield loss of 22.7% was calculated by multiplying the percentage of the affected area by an average yield loss conversion factor of 0.61 derived from all available data from greenhouse- and field-grown plants of several commercial pea cultivars.

scholarly journals Biological Control of Root Rot Complex of Pea (Pisum sativum L.)

2018 ◽  
Vol 46 (1) ◽  
pp. 49-67
Author(s):  
Naglaa Muhanna ◽  
Safa Elwan ◽  
Nsreen Dib
Keyword(s):  
Biological Control ◽  
Pisum Sativum ◽  
Root Rot ◽  
Pisum Sativum L

scholarly journals Use of One Cycle of Recurrent Selection per Year for Increasing Resistance to Aphanomyces Root Rot in Peas

1992 ◽  
Vol 117 (4) ◽  
pp. 638-642 ◽  
Author(s):  
Mark E. Lewis ◽  
Earl T. Gritton
Keyword(s):  
Pisum Sativum ◽  
Seed Yield ◽  
Root Rot ◽  
Recurrent Selection ◽  
Control Line ◽  
Aphanomyces Euteiches ◽  
Field Screening ◽  
Phenotypic Recurrent Selection ◽  
Selection Intensities

The effectiveness of one cycle (C) per year of phenotypic recurrent selection was evaluated for improving tolerance of peas (Pisum sativum L.) to aphanomyces root rot (Aphanomyces euteiches Drech.). Each cycle included field-screening a population of F2 lines (summer), diallel intermating among lines selected from the field (fall greenhouse), and one generation of selfing F1 plants (spring greenhouse) to produce F2 lines for the next cycle. The schedule is repeated for each cycle. A blocks-within-replicates design was employed in the field screening of C1 and C2 to improve within-block homogeneity. Selection intensities were 12.4%, 11.1%, and 10.6% for C0, C1, and C2, respectively. Using the performance of a tolerant control line, Mn 108, as a basis of comparison, the realized gain in dry seed yield and survival was 32% and 68% from C0 to C1 and 22% and 115% from C1 to C2, respectively.

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