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Integrated cereal crops disease

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  • INTEGRATED CEREAL CROPS DISEASE MANGMENTS IN IRIGATED AGRICULTURAL

    Prof. Mohamed Abdelkader Hasan

    Cereal Pathology

    PPI(ARC) [email protected]

  • INTEGRATED CEREAL CROPS DISEASE MANGMENTS IN IRIGATED AGRICULTURAL

    Cereal crops in irrigated area are suffering from many

    diseases

    Seed born

    diseases

    Foliar

    diseases

    PLANT DISEASES

    Plant disease is an impairment

    of the normal state of a plant

    that interrupts or modifies its

    vital functions

  • Disease infection leads to

    Complete damage to the economic part ( loose smut)

    Partial damage to the economic part (covered smut).

    Damage to the other parts (down mildew, powdery mildew, leaf spot and rusts)

    Missing plants (damping off, wilt)

    A biotic factors

    nutriments, pesticide exposure, environment pollution, temprature, moisture, & light.

    Biotic factors fungi, bacteria, nematodes, parasitic plants & virus

  • The Disease Triangle

    Environment

    Pathogen HostDISEASE

    Properties of PathogenLevel of virulence Adaptability Dispersal efficiency Survival efficiency Reproductive fitness

    Properties of HostSusceptibility Growth stage & form Population density & structure

    General healthProperties of Environment

    Temperature Rainfall / Dew Leaf wetness period Soil properties Wind

  • Plant disease can be

    Sporadic the disease appear on few host plant

    and distribute in a different places on the field

    Endemic the disease appear yearly on a

    regular basis and in moderate severity

    Epidemic the disease appear with high severity

    on most of the field and high

    sensitivity to the environmental

    conditions

  • Stages in Disease Development

    1) Inoculation

    2) Penetration

    3) Infection

    4)Growth and Reproduction

    5)Dissemination of Pathogen

  • 7

    Host Resistant Susceptible Disease reaction

    Pathogen Avirulent Virulent Pathogenicity

    Host:Pathogen

    Interaction

    Incompatible

    [Low]

    Compatible

    [High]

    Infection type or

    phenotype

    Concepts and terminology - host: pathogen interactionsConcepts and terminology - host: pathogen

    interactions

  • 8

    Resistant Susceptible

    and terminology

    Concepts and terminology -resistance and susceptibility

    A B

    0 1

    - At what level is the cut-off between resistance and susceptiblity?

    - Cultivar A is more resistant than cultivar B

    Resistance and susceptibility are relative terms - they represent a continuum on a scale - e.g. stripe rust, scale from 0 to 1:

  • Not all resistance provides a level of protection that will prevent yield losses:

    - Stripe rust resistance gene Yr18:

    - ffungicides protected plots - noloss

    - ssusceptible control - 75%loss

    - Yr18 line - 30%loss

    Breeders want resistance that is:easy to select, minimies yield loss, is durable

  • Plant Resistance: the retardation of infection and growth of a parasite on or with in host tissues.

    Monogenic resistance

    Race specific

    Polygenic resistanceRace non specific

    Fast lastDurable

    More than one gene (minor)

    Cultivarresistance

    One major gene

  • Identification resistance genes

    Should be done at pre breeding

    program

    Promising lines

  • Identification resistance genes

    1- Gene postulation( probable)

    2- Genetic analysis

    3- Using DNA markers

    Advantages:-

    1- Analysis can be done in several weeks

    2- Easy when only a few genes are present .

    Gene postulation

  • Disadvantages:-

    1- A collection of isolates differing in virulence is required.

    2- The presence of a gene is indicated but not proven.

    3- This method used only in identification of resistance

    genes that express in seedling plants and not

    appropriate for the identification of resistance genes that

    are expressed in adult plants.

    4-When more than one effective resistance gene is present in a

    cultivar or breeding line, the characteristic infection types of

    the individual genes are often altered due to interaction

    between the resistance genes.

  • 2- Genetic analysis

    Advantages:-

    1- Very accurate.

    2-This method used for identification resistance

    genes that express in seedling plants and also

    appropriate for the identification of resistance

    genes that are expressed in adult plants.

    Disadvantages:-

    1- This method needs at least 3 years for

    identification any resistance genes .

  • Advantages:

    Detects variations directly at DNA level

    Not influenced by environment

    Numerous in number

    Automation is possible

    Disadvantages:-

    Costs

    Trained peoples

    Molecular techniques

  • INTEGRATED CEREAL CROPS DISEASE (ICM)

    Is the causal organism really causing the problem?

    1st Step: Always identify causal organism before taking any action!

    Become familiar with its life cycle and habits

    Use the information to design a diseasemanagement plan

    Misidentification results in lack of knowledge = ineffective control of the real disease.

  • 1- Agricultural practices

    Planting timing (sowing date)

    spots Rust

    Wheat stem rust

  • Seed rate

    Crop rotation

    Preparation of suitable seed bed( soil born diseases)

    Irrigation

    fertilization

    Trap crops

    Powdery mildew Plant density will be high

  • Virus disease

    We must control the victor

  • Tolerant or resistant varieties

    2-Resistant varieties

    susceptible

    Resistant

  • Biological control

    In some cases we can use the natural enemies of the disease, fungi, bacteria and insect to reduce the disease severity

    Bacillus thuringiensis

  • Applied Chemical Control

    fungicide: any material that is applied to kill, attract, repel, or regulate the disease

    Advantages: effective, fast, easy

    Fungicide should be:

    *On the right time

    *recommended dose

  • fungicides vary by

    Mode of action: how they work to control the

    the disease

    Systemic fungicides are absorbed through tissues and transported elsewhere where the disease encounters it

    Contact fungicides must come in direct contact with the disease

  • Thank you