• Rapeseed and mustard form an important part of the total oilseed production in India. Among the different biotic stresses which influence the performance of rapeseed and mustard, Alternaria blight disease caused by Alternaria brassicae (Berk.) Sacc. is considered as one of the major yield attributing factor in West Bengal causing considerable losses to the crop. In view of the potentiality of the disease and its annual recurrence in unpredictable climatic condition facing off now in lateritic belt of West Bengal, attempts were made for studying the Alternaria blight of mustard with a view to get information on the existing isolates of the pathogen, their potential level of natural incidence, disease – environmental relationship and to explore the possibilities of controlling the disease with the help of SAR chemicals, biological agents and by selecting some resistant cultivars suitable for this location. An attempt was also made for development of a probable potent marker in relation to Alternaria blight resistance. RAPD profile analysis was carried out using different RAPD primers and extent of polymorphism with each primer was studied. Using the RAPD derived finger print profiles using selected primers, amplicon size for susceptible, moderately susceptible, highly susceptible and moderately resistant genotypes was also determined which formed the baseline for development of Alternaria blight resistant marker. Cluster analysis using morphological (epidemiological) traits and RAPD fingerprint profiles were also found to exhibit parallelism forming an important aspect of the study undertaken. This book is the final outcome of that exploratory/scientific research.

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        Introduction

I.      Background

2      Strategies for Disease Management

        Plants Elicitors

        Biological control or Biocontrol

        Host Plant Resistance

        Markers

        Statement of the Problem and Objectives of the Study

        Scope and Importance

3      Past Studies

        Symptomatology

        Geographical distribution

        Yield loss

4      The Pathogen

        Taxonomic position

        Host range

        Disease cycle

        Process of infection and pathogenesis

5      Epidemiology

        Disease development in relation to environmental conditions

        Physiological changes in host during infection

        Phytotoxins

        Host resistance

        Disease Management

        Molecular marker technology (M.M.T.)

        Marker assisted selection (MAS)

        Combined marker assisted selection

        Advantages of MAS over conventional methods

        MAS versus phenotypic selection

        Molecular mapping of disease resistance genes

        Determining probable potent marker in relation to disease resistance

        Overview of “Review of Literature”

6      Research Methodology

        Experimental site

        Agro-climatic conditions of the experimental site

        Cropping history of the experimental field

        Land preparation

        Application of manures and fertilizers

        Varieties grown

        Experimental design

        Calendar of operations

        Preparation of media

        Collection and maintenance of Alternaria isolates

        Collection of infected plant samples

        Cleaning of glass wares and slides

        Sterilization in hot air oven

        Sterilization of media in autoclave

        Studies on morphological variability of Alternaria brassicae

        Survey on the natural incidence of Alternaria leaf blight of rapeseed and mustard

        Evaluation of different abiotic chemical agents (elicitor compounds) for management of Alternaria leaf blight

        Evaluation of different biological control agents for management of Alternaria leaf blight

        Screening of rapeseed-mustard germplasms for their resistance against Alternaria blight under natural conditions

        Studies on the effect of Alternaria leaf blight on the yield components of different rapeseed-mustard varieties

        Influence of environmental factors on Alternaria leaf blight development on rapeseed-mustard

        Methods of statistical analysis

        Development of molecular marker linked with Alternaria blight of rapeseed and mustard

7      Results and Discussion

• Findings of Objective 1: To study the morphological variability of A. brassicae present in the undulating red and lateritic zone of West Bengal
• Findings of Objective 2: To study the natural incidence of Alternaria leaf blight of rapeseed and mustard in the undulating red and lateritic zone of West Bengal.
• Findings of Objective 3: To evaluate different chemical agents (elicitor compounds) for management of A. brassicae induced leaf blight
• Findings of Objective 4: To evaluate different biocontrol agents for management of A. brassicae induced leaf blight
• Findings of Objective 5: To screen various genotypes grown in the undulating red and lateritic zone of West Bengal for seeking their resistance against the disease.
• Findings of Objective 6: To study the effect of Alternaria leaf blight on the yield components of different rapeseed and mustard varieties grown.
• Findings of Objective 7: To study the influence of environmental factors on the progress of Alternaria leaf spot of rapeseed and mustard
• Findings of Objective 8: To determine probable potent markers in relation to Alternaria blight resistance using RAPD derived fingerprint profiling

8      Summary and Conclusions

        Summary

        Scope for future research

Appendix

• Meteorological data in weekly representation for I crop season i.e. 2011- 2012
• Meteorological data in weekly representation for IIcrop season i.e. 2012- 2013
• Analysis of variance in CRD for average conidial length of different Alternaria brassicae isolates
• Analysis of variance

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