I= BIOLOGICAL CONTROL OF DIFFERENT SOIL BORNE FUNGAL DISEASES OF POTATO (SOLANUM TUBEROSUM L.) RAISED THROUGH TISSUE CULTURE BY USING VESICULAR ARBUSCULAR MYCORRHIZA AND OTHER ANTAGONISTIC FUNGI
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Title of Thesis
BIOLOGICAL CONTROL OF DIFFERENT SOIL BORNE FUNGAL DISEASES OF POTATO (SOLANUM TUBEROSUM L.) RAISED THROUGH TISSUE CULTURE BY USING VESICULAR ARBUSCULAR MYCORRHIZA AND OTHER ANTAGONISTIC FUNGI

Author(s)
Masood Khan Lodhi
Institute/University/Department Details
University of the Punjab
Session
2004
Subject
Botany
Number of Pages
240
Keywords (Extracted from title, table of contents and abstract of thesis)
fungal diseases, potato, solanum tuberosum l, fungal pathogens, vesicular arbuscular mycorrhiza, antagonistic fungi, aphid virus vectors, malt extract agar, potato dextrose agar

Abstract
The present research work presents the use of some fungal biotechnological techniques for biological control of soil borne fungal pathogens of potato (Solanum tuberosum L.) by employing vesicular arbuscular mycorrhiza and other antagonistic fungi i.e. Aspergillus niger (Van) Tiegh, and Trichoderma viride Pers with different soil amendments and variable ranges of pH and temperature under glasshouse, screen house and field conditions.

Because of aphid virus vectors, which transmit viruses in potatoes resulting in low yield, a study was conducted to determine the best season to raise healthy potato seed crop by avoiding aphid attack. The vector for the transmission of PLRV in potatoes is the green peach aphid (Myzus persicae Sulz). It was found that the population of Myzus persicae was maximum in the months of March and April. It was concluded that the spring crop in the plains of Punjab province is not fit for seed potato production purposes.

The potato planting materials i.e. plants and tubers were raised through tissue culture techniques of apical meristem culture, nodal stem cuttings, layering, micro propagation in in-vitro and in-vivo and micro tuberization in-vitro and multiplication of seed tubers. Plants were grown out under field conditions and under controlled conditions in glass houses through out the course of the study. Murashige and Skoog Medium of inorganic salts with various amendments both in solid and liquid media were used for the commercial production of micro plants and micro tubers in in-vitro propagation. The liquid medium proved most suitable to elucidate the virus problem in the potato crop. Virus free seed tubers and plants used in experiments were screened through Enzyme linked immunosorbent assay (ELISA) to detect the potato viruses i.e. PVX, PVY, PLRV and PVS.

An elaborate survey was carried out of endogonaceous spore density. Vesicular arbuscular mycorrhizal fungi status and pathogenic infections. This was done in the root systems and in rhizosphere soil of the four potato varieties approved by the Seed Council of Pakistan i.e. Cardinal, Desiree, (red skin) Diamant and Patrones (white skin), growing in different areas of Pakistan (Plains and Northern Hilly Areas). All major vesicular arbuscular mycorrhiza (V AM) forming fungi genera were found in both potato growing areas. During this study the significance of various potato pathogens was determined in these four potato varieties. The investigations took place in both hilly areas and plains of Pakistan using the potatoes crop raised through tissue culture. A survey was also carried out of mycoflora in the rhizosphere of potato plants and a number of potato pathogens were isolated and identified. Fungi were isolated on malt extract agar (MEA) and potato dextrose agar (PDA) media except for obligate parasites. The potato pathogens identified were Rhizoctonia solani Kuhn (stem canker and black scurf), Verticillium alba-atrum Reinke and Berth, V dahliae (Verticillium wilt), Fusarium oxysporum schlect, Fusarium .spp. (Fusarium wilt), Alternaria solani Soraner (early blight), Phytophthora infestans (Mont) de Bary (late blight), Spongospora subterranea (wallr) Lagerh, (Powdery scab) and Streptomyces scabies (Thaxt.) waks and Henric (common scab).

The preparations of culture media and inoculum were carried out on various types of substrata including agricultural byproducts. Amongst these, sorghum seeds and wheat straw were the most successful substrates for inoculum. They were treated with 0.1 normal (N) and 0.2 N concentration of sulfuric acid (H2SO4) before being inoculated with antagonistic fungi.

A new method was developed for the sterilization of compost and solid media through direct Sun light (Solarizaiton) at 60-75°C by polythene sheets covering.

It was observed that the single and dual inoculations of antagonists of Trichoderma viride and VAM resulted in significant control of R. solani, Fusarium oxysporum and Verticillium albo-atrum. Significant biocontrol of disease severity was also obtained with dual inoculations (VAM + Aspergillus niger) made against R. solani and Verticillium spp.

Fusarium oxysporum, the cause of wilting disease of potatoes, was suppressed and controlled biologically by using. T viride and VAM. There was a synergistic interaction of R. solani and F. oxysporum during interaction with each other and the wilt disease control in sterilized compost media.

Pre inoculations with VAM of tissue culture raised microplants from test tubes to glass houses showed considerable hardening toward water and light stresses and a reduced mortality rate.

Spongospora subterranea, the cause of powdery scab in potatoes, was controlled biologically through pre-inoculation of antagonist Trichoderma viride and by adjusting pH levels (i.e. 5.5 to 7.90) under field conditions by amending rhizosphere soils with Single Super Phosphate (SSP) and 1 N Sulphuric acid I-H2SO4.

Download Full Thesis
6466.35 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
313 KB
2 1 Introduction 1
314.59 KB
  1.1 Potato Production In Pakistan 5
  1.2 Potato Crop Cycle In Pakistan 7
  1.3 Seed Potato Production System In Pakistan 8
3 2 Literature Survey 12
418.12 KB
  2.1 Viral Diseases 0 F Potato 12
  2.2 Bacterial Diseases 0 F Potato 14
  2.3 Fungal Diseases 0 F Potato 16
  2.4 Bio-Control Of Fungal Potato Diseases 17
  2.5 Mycorrhiza As A Beneficial Soil Fungus 19
  2.6 Biological Control Of Fungal Diseases By Using Ant Agonistic Fungi 26
  2.7 Mycoparasitsm Of Pathogens By Antagonistic Fungi 28
  2.8 Volatile And Non-Volatile Substances 31
  2.9 Use Of Different Antagonistic Fungi In Potato And Other Crops 31
4 3 Materials And Methods 34
514.06 KB
  3.1 Potato Plant Characteristics 34
  3.2 Production Of Healthy Planting Materials 36
  3.4 Monitoring 0f Aphids 45
  3.5 Virus Testing Through Elisa (Enzyme Linked Immunosorbent Assay) Technique 46
  3.6 Planting Of Microplants , Rooted Cuttings And Microtubers Raised Through Tissue Culture Techniques In Soil Media 51
  3.7 The Isolation Of Soil Borne Potato Pathogens On Different Synthetic Media 58
  3.8 Preparation Of Substratum For Biological Control Of Soil Borne Fungal Diseases 61
5 4 Results 64
3942.3 KB
  4.1 Section -I: Screening Of Potato Viruses Through Enzyme Linked Immunosorbent Assay -Elisa Technique To Raise Healthy Seed Potato Stocks 64
  4.2 Section -Ii:-Survey Of Fungal Diseases Of Potato In Pakistan 77
  4.3 Section:-III-Biological Control Of Soil Borne Fungal Diseases Of Potato 105
6 5 Discussion 146
203.37 KB
  5.1 Conclusion 157
7 6 References 159
725.76 KB
  6.1 Appendix -I 207