eChapters

Miscellaneous causes of male infertility 

1. Failure of proper delivery of semen into the vagina

It may be secondary to lacerations of the ventral caudal portions of the glans penis with a fistulous opening of the urethra ventrally. In such case, at the time of ejaculation, neither semen is deposited in the middle portion of the vagina nor sprayed over the cervix. In addition, it is observed in rams following necrosis of most of the urethral process secondary to urinary calculi or lacerations or injury.

Advantages and limitations of artificial insemination

Artificial insemination is the first great biotechnology applied to improve reproduction and genetics of domestic animals. Artificial insemination includes the collection of semen from the male, semen assessment for quantity and quality, dilution with extender, preservation and then insemination. Artificial insemination (A.I.) is a breeding technique where semen with living sperm is deposited into the reproductive tract of a female who is in estrus by use of instruments. Artificial insemination is the most important single technique widely used worldwide to upgrade the genetic makeup of the farm animals. Artificial insemination can be performed in most of the domestic animals like cow, buffalo, mare, sow, bitch, queen cat, lambs, does etc. Due to invention of frozen semen technology, the extended semen doses can be preserved for years together and permit wide spread use of superior germplasm. Artificial insemination is a powerful tool mostly employed for livestock improvement. The advantages and limitations of frozen semen technology are enlisted below:

Semen collection in bulls and buffalo bulls

Semen collection from domestic animals is an art and skilled job to get maximum quantity and quality of an ejaculate. Ejaculation of semen in a male is a complex process and consists of several events sexual arousal, courtship, erection, penile protrusion, mounting, intromission, ejaculation, orgasm like reaction and dismounting. Ejaculation is the result of neuro-muscular stimulation that starts in the vas differentia and accessory sex glands. The semen ejaculation is finally brought about by the rhythmical contractions of penile musculature and urethra. The muscular contractions proceed progressively in waves, forcing the semen out of the external urethral orifice. To get good quality semen, the bulls must undergo all the related events of ejaculation. The semen collectors should have knowledge of inhibitory and stimulatory factors for the act of ejaculation in male domestic animals. The stimulatory factors are:

Semen evaluation alone should not be interpreted as the sole indicator of the fertility of bulls but it will provide significant information of the sexual apparatus. After receipt of the semen sample in the laboratory, it is kept in a hot water bath at 350C until the evaluation is complete. One has to prevent cold shock to the living sperm cells during the evaluation process. All the glassware and other items coming directly or indirectly in contact with the sperm cells should be sterilized properly and kept ready in a thermostatically controlled cabinet at body temperature. Sudden changes in exposure of semen to cold or hot temperature results in higher dead spermatozoa or sperm agglutination. Semen should not be exposed to sunlight, wind, chemicals, smoke, vibration and water. A single laboratory test is not sufficient to assess the semen quality and semen should be examined within a shortest possible time after ejaculation as mentioned below (Table 9.1).

Microscopic examination 

A phase contract microscope with biotherm (37o C) is necessary for correct evaluation of semen because the refractive index of spermatozoa differs slightly from that of the surrounding medium. The ordinary bright field microscope will not provide sufficient contrast between the spermatozoa and the medium. Under phase contrast microscope, the object will appear dark on a bright background. This is achieved by reducing the light passing through the object by half a wavelength compared to the light passing through the medium. The eyepiece has a magnifying capacity of 10X while the objectives have 10, 40 and 100X. This will provide the microscope the magnifications of 100, 400 and 1000. The lenses and eyepiece should be kept clean by wiping with tissue paper and distilled water. Xylol can also be used to remove greasy material. The microscope has to be kept in one place and covered with Perspex cover when not in use to avoid dust accumulation. Personnel familiar with the operation of a particular microscope alone should be allowed to handle the microscope, since lot of differences exist between different makes of microscopes. 

Good quality semen is more acidic than semen with lower sperm concentration. In contrast, bacterial contaminated semen and semen with more dead spermatozoa evolve ammonia that will increase pH of semen. In orchitis, seminal vesiculitis and epididymitis the pH of semen will be alkaline due to presence of pus. In azoospermic or necrozoospermic semen, the pH may be neutral or alkaline. pH variation may be due to change in season/climate and frequency of successive ejaculates. Depending on the concentration and activity of spermatozoa, the pH of semen varies. The narrow range pH (BDH) paper are more convenient in routine work. The first change in color is matched with color on the cover of booklet. Use of BDH capillary set is time consuming whereas digital pH meters are also being used. The normal pH range is depicted in Table 11.1.

Semen is admixture of secretions of testes containing spermatozoa and accessory sex glands. Spermatozoa are formed in the seminiferous tubules of the testes. The tubules contain a complex series of developing germ cells that ultimately form the male gametes. The spermatozoa are unique type of cells containing nucleus (head portion) and a tail. The acrosome is a double walled structure situated between the plasma membrane and the anterior portion of the sperm head and neck connects the sperm head with its tail.

The idea behind semen dilution is to extend its volume without affecting its fertility so that many females can be bred from an ejaculate. The basic components of semen extender are Tris buffer, fructose, glycerol, egg yolk and antibiotics.

The semen storage technology and glass ampoules were earlier developed in USA and French, Danish and West Germany introduced straw technique and in the mean time Japanese scientists developed pellet freezing method. 

1. Ampoule method 

The diluted semen is filled in ampoules after labeling, sealed, frozen and preserved in liquid nitrogen. For insemination, the ampoule is thawed in warm water of 37^ºC until liquidation then ampoule is cut and semen is drawn into glass catheter with the help of a sterile syringe and used for insemination. In this method, semen may not be contaminated and identification of semen is easy. However, the semen is frozen in a larger volume so the freezability and fertility are less and it requires more storage space in cryocan. About 8-10% of semen is lost while thawing, loading and insemination.  Use of glass catheter for insemination is risky because chances of breaking and chances of injury to cow or inseminator and passing of catheter in the cervix.

1. Preparation of diluents 

The diluent is prepared one hour before semen collection so that it is stabilized. The diluent is prepared by mixing the ingredients and kept ready in water bath at 30oC. One of the diluents is detailed below

Liquid nitrogen and cryocan

Several cryogenic agents like solid carbon-di-oxide (-79^ºC), liquid air (-183^ºC), liquid helium  (-263^ºC) and liquid nitrogen (-196^ºC) have been used in many countries for freezing and preservation of bovine semen. Liquid nitrogen is fourth coldest substance known and its small amount is converted into a very large amount (near about 700 times) of its volume when exposed to atmosphere. It is a colourless, odorless, non-irritant, non-toxic, non-caustic, non-corrosive, non-inflammatory and inert gas having boiling point of -196^ºC. Being a liquid it comes into good contact with the surface of the semen straws, constant storage temperature is maintained throughout the straw, and due to these properties LN2 is most widely used refrigerant for semen cryopreservation in the world. 

There is no rapid direct test to determine fertility of semen sample. During freezing and thawing of semen, 20-80% of the spermatozoa become immotile or dies. In addition to this, there may be damage to spermatozoa by disintegration of sperm cell membrane and acrosome leading to loss of intracellular enzymes. The only reliable method to evaluate the semen is to inseminate a cow and get a calf at the end of gestation period. Now-a-days new methods have been developed for in-vitro assessment of fertility of spermatozoa. Some of these methods are exhaustive, time consuming, need for a full-fledged analysis and difficult under field conditions.

1. AI with liquid semen

The ampoule is thawed in ice water for 6-7 minutes. Then, the ampoule is dried and cut. The semen is drawn in a sterilized glass pipette (40-42 cm x 5 mm length diameter) fitted to a sterile glass/plastic syringe (2-5 mL) filled with 1 mL of semen with a rubber connecter. Artificial insemination is done by recto-vaginal method after securing cow/buffalo in standing position in the trevis.

The reproductive efficiency in dairy herd is one of the important factor in determining total production and profitability. To remain profitable, dairy cows must reproduce at greatest efficiency and should calve every year (12-13 months). The measure of fertility in a herd is the calving rate (percentage of live, normal calves born). However, it is also necessary to measure fertility based on services per conception. In a healthy herd in which fertile bulls are used, an average of about 1.6 to 1.7 services is required per conception. The number of services per conception is particularly useful for analyzing costs and in comprising the A.I. quite similar to that obtained through natural service in well managed herds. Another measure of fertility is the non-return rate that is calculated from insemination records. Non-return rate is the percentage of cows that are not subsequently rebred within a defined period (60 to 90 days) following an insemination. On an average, about 70% percent of cows inseminated fail to return for service after first service on a 60 to 90 days non-return basis.

The spermatogenesis is a continuous process in male animals but affected by following factors. 
    
1.     Genetic makeup of male animal: Certain sperm defects like Diadem defect, knobbed sperm, decapitated sperm, sterilizing tail stump, corkscrew mid piece and narrow head are inherited defects and reported in certain males. Few inherited genetic factors are also associated with poor libido and poor fertility. Inherited sperm defects affect sperm motility, fertilization and embryo formation.

The progress of AI organization depends upon the type of service over and above that initially expected by the members. A well-conducted field service is very important in expanding the growth of any breeding organization. It includes activities as publicity, cooperation in health control, production testing and culling and progeny appraisal, the holding of demonstrations and open house and participation in cattle shows. The salary of a technician with bonus incentive encourages to do work of a high order. The semen costs per inseminated cow can be reduced by maintaining highest quality standards in producing, processing and shipping, by increasing number of cow serviced and by cutting all unnecessary costs. When breeding efficiency is high, the required amount of semen is kept at a minimum. An increase in cows inseminated is a key factor in keeping an organization in the back.

The information in respect of reproductive parameters and events are recorded in respect of following points.
    
1.    Date of semen collection, evaluation, preservation and semen distribution from different bulls 
    
2.    Fertility status of semen 
    
3.    Reproductive performance of females 
    
4.    Work of inseminators

Immediately after use, all sorts of items are thoroughly washed with water and the rubber catheters are washed with the force of tap water to remove the residual diluted semen. The glass wares are kept in 1% chromic acid solution for overnight to remove cloudiness of glass surface. Then the articles are washed with lukewarm laboratory grade detergent (ex. Labolene®) with a brush to make the articles grease free. All the items are thoroughly washed several times under distilled water and kept inverted position in a clean trough then the openings of glassware wrapped with aluminum foil / paper.

Breeding soundness examination can be used as a diagnostic aid in herd fertility problems. After breeding soundness examination, a bull is classified as a satisfactory potential breeder, a questionable potential breeder or an unsatisfactory potential breeder. Members of the Society for Theriogenology developed the concept of a breeding soundness examination as mentioned below.

The first buffalo AI progeny is reported at Allahabad in August 1943. Although AI is commonly used as a tool of breeding in buffaloes and complaints have appended that conception rate is not satisfactory. There are differences in the anatomy of the sexual organs, sexual physiology and general breeding behaviour that have to be known and taken into consideration when the same technique of AI used in cattle is applied in buffalo breeding. It explains the lower semen production capacity of male buffaloes compared to the cattle bulls. The buffalo bull’s penis is shorter and thinner than penis of the cattle bull. There is a pronounced tapering of the penile end and glans penis is rather poorly developed. The thrust is shorter and less forceful than the bulls. The sheath is tighter and closer to the abdomen than zebu cattle. These anatomical differences are of significance in the semen collection work and type of artificial vagina to be used. The weight of testis and epididymidis in the male buffalo is only ¼ of what it is in cattle. In addition, the seminal vesicles and the prostate are considerably smaller.

Artificial insemination in horses is being practiced since many years in Russia and China for genetic up-gradation. The equine artificial insemination industry has evolved a system in which mares are inseminated with fresh or cooled semen (500 million motile sperm) every 48 hours until estrus is no longer detected or until ovulation is detected by trans-rectal palpation or ultrasonography of ovaries respectively. The advantages of AI include:

Artificial insemination (AI) technique in pigs is being performed since several decades in many countries but not widely accepted technology as in cattle due to reasons like sub-standard method of semen cryopreservation and lower fertility rate. The main idea is to increase the breeding efficiency by utilization of superior boars. The number of boars needed for breeding purposes can be reduced by use of AI and reduced transmission of infectious diseases. A minimum of 15 to 20 sows can be inseminated after dilution over a 2 days period with an ejaculate from a boar. Artificial insemination had considerable impact worldwide in its application to commercial pig production. The main advantage of using fresh liquid boar semen is that fertility is maintained even with low number of spermatozoa in the inseminate. AI provides unique opportunity for the genetic improvement of pig industry. Using fewer than 1 million sperm cells per breeding unit can achieve conception rates with liquid semen similar to those with frozen thawed semen containing approximately 15 million sperm and reduced fertility makes cryopreservation an uneconomical option in boars.

Artificial insemination Technology is a high cost and labour intensive technique in sheep and In India, sheep are reared by economically weaker sections of the society and any advanced technique may take much time to reach their flocks.  Considerably more research work has been done in AI with sheep than with goats. However, the equipment and techniques are very similar for the two species. Goat semen may be stored and frozen more successfully than ram semen.

Artificial insemination technology is a valuable tool to inseminate 2000 to 3000 does by frozen semen instead of breeding 40 to 50 does by natural service in a year. Goat semen may be stored and frozen more successfully than ram semen. The buck will be sexually mature at 6-7 months of age.

Castration means removal of the testicles and there are two methods of castration in domestic animals viz. closed and open method.

1. Closed method

In closed method, without incision, the spermatic cord is crushed where thrombus is formed which arrest blood flow to the testicles resulting in gradual atrophy of the testicles. ex. Burdizzo method

1.1     Prokaryotic 
    
1.2     Eukaryotic
    
1.3     Cell orgenellie

2.1     Regulation of the Cell Cycle 
    
2.2     Mitosis
    
2.3     Meiosis

DNA (deoxyribonucleic acid), the giant molecule that carries genetic information in living things, is made up of just a few chemical building blocks that bond together in very particular ways. A typical molecule of DNA consists of two strands that are linked together. A segment can be visualized as a ladder-like structure:

The DNA as made of two strands, a left and a right, which are linked in the middle. In reality, since the ladder is twisted, there really is no “right” or “left,” but we use that terminology here since it applies to the model graphs. The square shapes and diamonds you see in the middles of the “rungs” are the links, which are meant to represent the different chemical bonds between the two strands of DNA.

4.1 DNA: The word means
    
4.2 Double Helical Structure: The Watson and Crick Model
    
4.3 Family of DNA 
    
4.4 The Chromosomes

5.1 Replication
    DNA Replication in Bacteria
    DNA Replication in Eukaryotes
    
5.2 Transcription

5.3 Translation

6.1 Prokaryotic Gene Expression
    
6.2 The lac  Operon
    
6.3 The trp  Operon

7.1 Gel Electrophoresis
    
7.2 Polymerase Chain Reaction (PCR)
    
7.3 Restriction Fragment Length Polymorphisms (RFLPs)
    
7.4 Random Amplification of Polymorphic DNA (RAPD)
    
7.5 Amplified Restriction Fragment Length Polymorphism (AFLP)

8.1 Sub Cloning
    
8.2 Cloning into a Yeast Artificial Chromosome (YAC)
    
8.3 DNA Libraries

9.1 Methylases
    
9.2 Polymerases
    
9.3 Nucleases
    
9.4 Ligases
    
9.5 Phosphatase
    
9.6 Topoisomerase
    
9.7 Restriction enzymes

10.1 Plasmids
    
10.2 Retrovirus

11.1 Total DNA Extraction by cTAB Method
    
11.2 Extraction, Purification Estimation of DNA
    
11.3 Potassium Acetate Procedure
    
11.4 DNA  Estimation
    
11.5 Restriction Enzymes

Acetic acid            
    

Molecular weight    60.05        
    Melting point (^ºC)    17        
    Boiling point (^ºC)    118        
    Flash point (^ºC)    40        
    Auto-ignition point (^ºC)    426        
    Specific gravity at 20^ºC    1.05        
    Molarity of the concentrated acid (M)    17.4    
    1 M solution    57.5 ml concentrated acid per litre

1.1    General Circulation of the Atmosphere
    
1.2    World Climates
    
1.3    World Climate Classification by Köppen’s method
    
1.4    Climatic Classification over India
    
1.5    Asian Summer Monsoon and Rainfall Distribution
    
1.6    The Indian Monsoon
    Features of monsoon
    Monsoon circulation
    Onset of monsoon
    Withdrawal of monsoon
    Southwest monsoon rainfall
    Active phase of monsoon
    Break monsoon conditions
    Winter monsoon

1.7    Causes for Failure of Monsoon
    
    Prediction of onset of monsoon rainfall

1.8    Spatial Distribution of Weather Parameters over India
    Rainfall
    Temperature
    Humidity
    Sunshine and Radiation
    Wind speed

1.9    Famines in India
    
1.10    Historical Evidences of Droughts
    
1.11    Distribution of Drought Prone Regions over the Globe
    1.11.1    Occurance of drought in different countries
    
1.12    Distribution of Drought Prone Regions in India
    
1.13    Weather Phenomena Associated with Droughts
    
1.14    Effect of Droughts on Natural Resources
    1.14.1    Surface water resources
    1.14.2    Groundwater sources
    
1.15    Impact of Latest Droughts on Crop Production in India
    
1.16    Economic Impacts of Droughts in India
    
1.17    Economic Impacts of Droughts in other Nations
        
References

2.1    Definition of Droughts
    
2.2    Types of Droughts
    2.2.1    Meteorological Droughts
    2.2.2    Agricultural Droughts
    2.2.3    Hydrological Droughts
    2.2.4    Socio-economic Droughts
    
2.3    Criteria for Classification of Droughts
    Meteorological Droughts
    Agricultural Droughts
    Hydrological Droughts
    
2.4    Data requirements in Drought Analysis
    
2.5    Drought Indices
    2.5.1    Rainfall-based Indices
    2.5.2    Climate Derivate Based Indices
    2.5.3    Remote Sensing Based Indices
    2.5.4    Processes Based Indicators
    
2.6    Assessment of Drought Prone Regions in India
    
2.7    Indicators for Declaration of  Droughts in India
    2.7.1     Rainfall Deficiency
    2.7.2    Area Under Sowing
    2.7.3    Normalized Difference Vegetation Index
    
2.8    Drought Management Procedures in India
    
2.9    Drought Code adopted by Local Governments
    
2.10    Spatial Variability of Droughts and their Frequency of Occurrence in India
    
2.11    Drought Vulnerability Assessment
    
2.12    Vulnerability of Society to Drought
        
References

3.1    Factors Contributing to Climate Change
    3.1.1    Natural Causes to Climate Change
    3.1.2    Human Causes to Climate Change
    
3.2    Climatic Trends
    3.2.1    Global level
    3.2.2    National level
    
3.3    Climate Projections
    3.3.1    Global level Projections on Future Changes in Climate
    3.3.2    Climate Projections at the National level
    3.3.3    Climate Projections at the Regional level
    3.3.4    Projections of Extremes in Rainfall and Temperature
    
3.4    Consequences of Climate Change on Droughts and Agriculture
    3.4.1    Impact of Climate Change on Agriculture in some States of India
    
References

4.1    Approaches for Drought Monitoring
    
4.2    Weather Network System in Different Countries
    
4.3    Drought Monitoring using Climatological, Hydrological and Combination Approaches in Different Countries
    
4.4    International Cooperation in Drought Monitoring
    
4.5    Drought Monitoring Mechanism in India
    
4.6    Early Warning and Decision Support System
    4.6.1    Software for Drought Detection, Monitoring and Early Warning
    4.6.2    Decision Support System for Droughts Developed Outside India
    
4.7    GIS and Drought Monitoring
        
References

5.1    Global Food Production
    5.1.1    Area Under Cultivation
    5.1.2    World Food Production
    
5.2    Variability in Global and Indian Food Grain Production
    
5.3    Impact of Phenomenal Drought During 2009 on Food Grain Production in Different Countries
    
5.4    Impacts on Livestock and Fisheries
    5.4.1    Livestock
    5.4.2       Milk Production
    5.4.3    Fisheries
    
5.5    Estimation of Food Grain Production in India using Rainfall indices
    5.5.1    Trend in the annual food grain production
    5.5.2    De-trended production index
    5.5.3    Construction of rainfall indices (RI)
    5.5.4    Development of model for estimation of production index
    5.5.5    Verification of model performance
    5.5.6    Estimation of Kharif Price Production
    
5.6    Forecasting of Agricultural Output Using Space, Agrometeorology and Land based Observation (FASAL)
        
References

6.1    Hydrological Cycle
    
6.2    Global Surface Waters
    
6.3    Surface Water over India
    
6.4    Ground Water Potentials in India
    
6.5    Influence of Drought on Water Resources, its Fauna and Flora
    6.5.1    Effects on Fauna and Flora
    
6.6    Influence of Changing Climate on Droughts and Water Resources
    6.6.1    Global warming and droughts at global scale
    6.6.2    Global warming on water resources at global scale
    6.6.3    Global warming and droughts at national scale in India
    6.6.4    Global warming impacts on water resources at National scale
        
References

Good Practices for Drought Management
    7.1    Drought Planning and Preparedness
    7.1.1    Drought Planning in India
    7.2    Global Experiences in Drought Planning
    7.2.1    USA
    7.2.2    South Africa
    7.2.3    African Nations
    7.2.4    Namibia
    7.2.5    Ethiopia
    7.2.6    Botswana
Drought management plans in Europe
    7.2.7    Spain
    7.2.8    England and Wales
    7.2.9    Portugal
    7.2.10    Australia
    7.2.11    China
    7.2.12    Palestine
    7.2.13    Global Initiatives
    7.3    Drought Preparedness Action Plans in India
    7.3.1    Drought Preparedness Checklist
    7.4    Drought Preparedness Action Plans in Different Countries
    7.4.1    Arizona State in USA
    7.4.2    Texas State in USA
    7.4.3    Italy
    7.4.4    Mediterranean Region
    7.4.5    Pakistan
    7.4.6    Darfur in Sudan
    7.4.7    Bangladesh
    7.5    Indigenous Knowledge for Drought Management
    7.5.1    Astro Meteorological Methods
    7.5.2    Traditional Knowledge in Weather Prediction
     7.5.3    Traditional wisdom in Drought Risk Region (DRR)
        Rajasthan and Bundelkhand region in Uttar Pradesh
    7.5.4    Indigenous technologies for moisture conservation 
        in dry lands of semi-arid regions of India
    7.6    Traditional Wisdom for Drought Management in a few selected countries
    7.7    Role of Weather-based Agro-advisories
    7.7.1    Strategies for dissemination of advisories
    7.7.2    Role of ICAR and AICRPAM on Agromet Services
    7.7.3    Agromet Advisory services through mobile phone
    7.7.4    Status of Agromet Advisory Services in other Countries
    7.8    Value Addition to Agromet Information
    7.8.1    AICRP on Agrometeorology
    7.8.2    Thumb rules for weather-pest/diseases
    7.9    Contingency Crop Planning for Minimizing Risks
    7.9.1    Contingency Crop Planning for Rainfed Regions of India
    7.10    Drought Proofing Mechanisms
    7.10.1    Watershed Development for Drought Management
    7.10.2    Watershed Development in India
    7.10.3    The Success Stories of Watershed as a Drought Proofing Mechanism
    7.10.4    Watershed Policies and Recommendations
    7.10.5    Farm Ponds for Drought Management
    7.10.6    Success Stories of Farm Ponds
    7.11    Rainfed Technologies for the Drought Management in different agro climatic region
    7.12    Farmer’s Awareness on Climate Management
    7.12.1    India
    7.12.2    In other Countries
    7.13    Role of ICT in Climate Risk Management through AAS
    7.13.1    India
    7.13.2    Application of ICT in Providing Advisories in other Countries
    7.14    Integrated Drought Management Strategies through Farming Systems Approach
    7.14.1    Drought Adaptation Strategies in Rajasthan and in Maharashtra
    7.14.2    Improvement and Rural Livelihood
    7.15    Drought Mitigation Measures
    7.15.1    Drought Mitigation Plans
    7.15.2    Soil water Conservation and Recharging of Ground water Methods
    7.15.3    Traditional Water Harvesting and Conservation 
        Techniques
        References

Review of the state of art of Drought on impact assessment, monitoring and management with special reference to agricultural production has revealed that Drought is still a complex natural disaster and difficult to forewarn in spite of advancements in atmospheric sciences and computational procedures. It is realized only after it is set in and is not known when it is likely to withdraw. A long way one has to travel to predict its occurrence, spread and its continuation to the next season over a region. The existing net work of observational set up in developing countries in Africa, Asia and in South America need to be strengthened further for effective monitoring of significant weather events at regional and micro regional level. With the rapid expansion of communication system over the past two decades, establishment of Automatic Weather Stations (AWS) at as many locations as possible even in remote regions should be taken up on priority basis and funding may be provided by the respective governments or by the International Organizations where ever necessary. Nations with limited resources may also be convinced to strengthen their weather observational net work in view of the increased occurrences of climate extremes and changing climate. Drought vulnerability regions over the globe were delineated based on sparse historical weather data which do not match with real surface conditions. Now, with the availability of weather data from more number of stations both temporally and spatially, drought prone regions over the world may be re-delineated. This would help the planners to allocate funds rationally to the affected regions. Globally every year, some regions or others may be experiencing droughts and more so in drought prone regions.

1.    Anthracnose
    
2.    Powdery mildew
        
3.    Mango malformation
        
4.    Red rust
        
5.    Grey blight
        
6.    Sooty mould
        
7.    Stem end rot
        
8.    Bacterial leaf spot

1.    Panama wilt
        
2.    Moko or Bacterial wilt
        
3.    Sigatoka disease
        
4.    Anthracnose
        
5.    Bunchy Top

1.    Downy mildew
        
2.    Powdery mildew
        
3.    Anthracnose/Bird’s eye spot

1.    Gummosis
        
2.    Canker
        
3.    Scab/Verucosis
        
4.    Tristeza or quick decline
        
5.    Greening
        
6.    Exocortis or scaly butt

1.    Wilt
        
2.    Anthracnose
        
3.    Canker