Strategies for enhancement in food production
Animal husbandry
· It is the agricultural practice of breeding and raising livestock (usually goat, sheep, buffaloes, cows, pigs, horses, cattle etc.; also extended to fish, poultry )
· Both science as well as art
· Fisheries include rearing, catching, selling etc., of fish, mollusks (shell – fish) and crustaceans (prawns, crabs etc.)
· >70 % of the world livestock populations (< 25% production) is in India and China
· Productivity per unit is very low
· Newer technologies need to be applied for improving quality and productivity of livestock
1. Management of farms and farm animals
1.1. Dairy Farm Management:
· Dairying is the management of animals for milk and its products for human consumption.
· Dairy farm management deals with processes and systems that increase yield and improve quality of milk.
· Milk quality depends on quality of breeds
Good quality breeds: Characteristics
1. High yielding potential (milk production)
2. Resistance to diseases
3. Adaptability to climatic conditions
To realize high yield potential:
1. Proper housing facilities
2. Adequate water availability
3. Disease free maintenance
4. Sufficient quantity of good quality fodder
Milking, storage and transport of milk and milk products:
· Stringent cleanliness and hygiene of both cattle and handlers
· Nowadays –mechanized handling (reduces contamination by handler)
Scientific management of dairy farms:
1. Stringent cleanliness and hygiene of both cattle and handlers
2. Regular inspections
3. Proper record keeping
4. Regular visits by a veterinary doctor (mandatory)
9.1.1.2 Poultry Farm Management
Ø Poultry is the class of domesticated fowl (birds) used for food or for their eggs. They typically include chicken and ducks, and sometimes turkey and geese.
Ø The word poultry is often used to refer to the meat of only these birds, but in a more general sense it may refer to the meat of other birds too.
Important components of poultry farm management:
· selection of disease free and suitable breeds,
· proper and safe farm conditions,
· proper feed and water, and
· hygiene and health care
9.1.2 Animal Breeding
Breeding of animals - an important aspect of animal husbandry.
Animal breeding aims at increasing the yield of animals and improving the desirable qualities of the
produce.
Breed: A group of animals related by descent and similar in most characters like general appearance, features, size, configuration, etc.,
Some common breeds of cattle and poultry: (a) Jersey (Cattle) (b) Leghorn (Poultry)
Inbreeding: Inbreeding refers to the mating of more closely related individuals within the same breed for 4-6 generations.
The breeding strategy:
Ø superior males and superior females of the same breed are identified and mated in pairs.
Ø The progeny obtained from such matings are evaluated and superior males and females among them are identified for further mating.
Ø A superior female, in the case of cattle, is the cow or buffalo that produces more milk per lactation.
Ø On the other hand, a superior male is the bull, which gives rise to superior progeny as compared to those of other males.
Ø Inbreeding increases homozygosity.
Ø Thus inbreeding is necessary if we want to evolve a pureline in any animal.
Ø Inbreeding exposes harmful recessive genes that are eliminated by selection.
Ø It also helps in accumulation of superior genes and elimination of less desirable genes.
Ø this approach increases the productivity of inbred population.
Ø However, continued inbreeding, especially close inbreeding, usually reduces fertility and even
productivity. This is called inbreeding depression.
Ø Whenever this becomes a problem, selected animals of the breeding population should be mated with unrelated superior animals of the same breed. This usually helps restore fertility and yield.
Out-breeding : Out-breeding is the breeding of the unrelated animals, which may be between individuals of the same breed (but having no common ancestors), or between different breeds (cross-breeding) or different species (inter-specific hybridisation).
Out-crossing: This is the practice of mating of animals within the same breed, but having no common ancestors on either side of their pedigree up to 4-6 generations. The offspring of such a mating is known as an out-cross.
Ø It is the best breeding method for animals that are below average in productivity in milk production, growth rate in beef cattle, etc.
Ø A single outcross often helps to overcome inbreeding depression.
Cross-breeding: In this method, superior males of one breed are mated with superior females of another breed.
Ø Cross-breeding allows the desirable qualities of two different breeds to be combined. The progeny hybrid animals may themselves be used for commercial production.
Ø Alternatively, they may be subjected to some form of inbreeding and selection to develop new stable breeds that may be superior to the existing breeds.
Ø Many new animal breeds have been developed by this approach.
Hisardale is a new breed of sheep developed in Punjab by crossing
Bikaneri ewes and Marino rams.
Interspecific hybridisation: In this method, male and female animals of two different species are mated. In some cases, the progeny may combine desirable features of both the parents, and may be of considerable economic value, e.g., the mule
Mules are the cross between a male donkey and a female horse, and hinnies are the cross between a male horse and female donkey.
Artificial insemination: The semen is collected from the male that is chosen as a parent and injected into the reproductive tract of the selected female by the breeder. The semen may be used immediately or can be frozen and used at a later date. It can also be transported in a frozen form to where the female is housed.
Multiple Ovulation Embryo Transfer Technology (MOET): is one such programme for herd improvement. In this method, a cow is administered hormones, with FSH-like activity, to induce follicular maturation and super ovulation instead of one egg, which they normally yield per cycle, they
produce 6-8 eggs. The animal is either mated with an elite bull or artificially inseminated. The fertilised eggs at 832 cells stages, are recovered non- surgically and transferred to surrogate mothers. The genetic mother is available for another round of super ovulation.
This technology has been demonstrated for cattle, sheep, rabbits, buffaloes, mares, etc. High milk-
yielding breeds of females and high quality (lean meat with less lipid) meat-yielding bulls have been bred successfully to increase herd size in a short time.
9.1.3 Bee-keeping
Bee-keeping or apiculture is the maintenance of hives of honeybees for the production of honey.
Ø It has been an age-old cottage industry.
Ø Honey is a food of high nutritive value and also finds use in the indigenous
systems of medicine.
Ø Honeybee also produces beeswax, which finds many uses in industry, such as in the preparation of cosmetics and polishes of various kinds.
Ø Bee-keeping can be practiced in any area where there are sufficient
bee pastures of some wild shrubs, fruit orchards and cultivated crops.
Ø There are several species of honeybees which can be reared. Of these, the most common species is Apis indica.
Ø Beehives can be kept in one's courtyard, on the verandah of the house or even on the roof. Bee-keeping is not labour-intensive.
Ø Bee-keeping though relatively easy does require some specialized knowledge and there are several organisations that teach bee-keeping.
Important points for successful bee-keeping:
1. Knowledge of the nature and habits of bees,
2. Selection of suitable location for keeping the beehives,
3. Catching and hiving of swarms (group of bees),
4. Management of beehives during different seasons, and
5. Handling and collection of honey and of beeswax.
ü Bees are the pollinators of many of our crop species such as sunflower, Brassica, apple and pear. Keeping beehives in crop fields during flowering period increases pollination efficiency and improves the yield beneficial both from the point of view of crop yield and honey yield.
9.1.4 Fisheries
Ø Fishery is an industry devoted to the catching, processing or selling of fish, shellfish or other aquatic animals.
Ø A large number of our population is dependent on fish, fish products and other aquatic animals such as prawn, crab, lobster, edible oyster, etc., for food.
Ø Some of the freshwater fishes which are very common include Catla, Rohu and common carp. Some of the marine fishes that are eaten include Hilsa, Sardines, Mackerel and Pomfrets.
Ø Fisheries has an important place in Indian economy. It provides income and employment to millions of fishermen and farmers, particularly in the coastal states. For many, it is the only source of their livelihood.
Ø through aquaculture and pisciculture we have been able to increase the production of aquatic plants and animals, both fresh-water and marine.
Ø Pisciculture refers to the breeding, hatching, and rearing of fish under controlled conditions.
Ø Aquaculture is the cultivation of aquatic organisms. Unlike fishing, aquaculture, also known as aquafarming, implies the cultivation of aquatic populations under controlled conditions.
Ø Mariculture refers to aquaculture practiced in marine environments. Particular kinds of aquaculture include algaculture (the production of kelp/seaweed and other algae); fish farming; shrimp farming, shellfish farming, and the growing of cultured pearls aquaculture.
Ø Blue Revolution is the water equivalent of the green revolution and primarily refers to the management of water resources that can steer humanity to achieve drinking water and crop irrigation security.
9.2 PLANT BREEDING
ü Green revolution was dependent to a large extent on plant breeding techniques for development of high-yielding and disease resistant varieties in wheat, rice, maize, etc.
What is Plant Breeding?
Ø Plant breeding is the purposeful manipulation of plant species in order to create desired plant types that are better suited for cultivation, give better yields and are disease resistant.
Ø evidence of plant breeding dates back to 9,000-11,000 years ago.
Ø Many present-day crops are the result of domestication in ancient times.
Ø Today, all our major food crops are derived from domesticated varieties.
Ø Classical plant breeding involves crossing or hybridisation of pure lines,
followed by artificial selection to produce plants with desirable traits of higher
yield, nutrition and resistance to diseases.
Ø plant breeding is now increasingly being carried out by using molecular genetic tools.
List the traits or characters that the breeders try to incorporate into crop plants:
· increased crop yield and improved quality.
· Increased tolerance to environmental stresses (salinity, extreme temperatures, drought),
· resistance to pathogens (viruses, fungi and bacteria) and
· increased tolerance to insect pests would
The main steps in breeding a new genetic variety of a crop are
(i) Collection of variability:
ü Genetic variability is the root of any breeding programme. In many crops pre-existing genetic variability is available from wild relatives of the crop.
ü Collection and preservation of all the different wild varieties, species and relatives of the cultivated species (followed by their evaluation for their characteristics) is a pre-requisite for effective exploitation of natural genes available in the populations.
ü Germplasm collection: The entire collection (of plants/seeds) having all the diverse alleles for all genes in a given crop
(ii) Evaluation and selection of parents:
ü The germplasm is evaluated to identify plants with desirable combination of characters.
ü The selected plants are multiplied and used in the process of hybridisation.
ü Purelines are created wherever desirable and possible.
(iii) Cross hybridisation among the selected parents:
ü The desired characters have very often to be combined from two different plants
(parents), for example high protein quality of one parent may need to be combined with disease resistance from another parent.
ü This is possible by cross hybridising the two parents to produce hybrids that genetically combine the desired characters in one plant.
ü This is a very time-consuming and tedious process
ü Also, it is not necessary that the hybrids do combine the desirable characters; usually only one in few hundred to a thousand crosses shows the desirable combination.
(iv) Selection and testing of superior recombinants:
ü Plants, among the progeny of the hybrids, that have the desired character combination are selected (plants superior than both parents)
ü very often more than one superior progeny plant may become available. These are self-pollinated for several generations till they reach a state of uniformity (homozygosity), so that the characters will not segregate in the progeny.
(v) Testing, release and commercialisation of new cultivars:
ü The newly selected lines are evaluated for their yield and other agronomic traits of quality, disease resistance, etc. in the research fields and their performance is recorded under ideal fertiliser application, irrigation, and other crop management practices.
ü The evaluation in research fields is followed by testing the materials in farmers' fields, for at least three growing seasons at several locations in the country, representing all the agroclimatic zones where the crop is usually grown. The material is evaluated in comparison to the best available local crop cultivar a check or reference cultivar.
Indian Agriculture
Ø India is mainly an agricultural country.
Ø Agriculture accounts for approximately 33 per cent of India's GDP and
Ø employs nearly 62 per cent of the population.
Challenges after India's independence,
ü one of the main challenges facing the country was that of producing enough food for the
increasing population.
ü As only limited land is fit for cultivation, India has to strive to increase yields per unit area from existing farm land.
Green Revolution : The development of several high yielding varieties of wheat and rice in the mid-1960s, as a result of various plant breeding techniques led to dramatic increase in food production in our country. This phase is often referred to as the Green Revolution.
Wheat and Rice:
1960 to 2000
ü wheat production increased from 11 million tones to 75 million tonnes
ü rice production went up from 35 million tonnes to 89.5 million tonnes.
Reason for increase:
ü development of semi-dwarf varieties of wheat and rice.
Wheat: Nobel laureate Norman E. Borlaug, at International Centre for Wheat and Maize
Improvement in Mexico, developed semi-dwarf wheat. In 1963, several varieties such as Sonalika and Kalyan Sona, which were high yielding and disease resistant, were introduced all over the wheat-growing belt of India.
Rice: Semi-dwarf rice varieties were derived from IR-8, (developed at International Rice Research Institute (IRRI), Philippines) and Taichung Native-1 (from Taiwan). The derivatives were introduced in 1966. Later better-yielding semi-dwarf varieties Jaya and Ratna were developed in India.
Sugar cane: Saccharum barberi was originally grown in north India, but had poor sugar content and yield. Tropical canes grown in south India Saccharum officinarum had thicker stems and higher sugar content but did not grow well in north India. These two species were successfully crossed to get sugar cane varieties combining the desirable qualities of high yield, thick stems, high sugar and ability to grow in the sugar cane areas of north India.
Millets: Hybrid maize, jowar and bajra have been successfully developed in India. Hybrid breeding have led to the development of several high yielding varieties resistant to water stress.
9.2.2 Plant Breeding for Disease Resistance
ü Crop losses due to diseases can often be significant, up to 20-30 per cent, or sometimes even total.
ü Breeding and development of cultivars resistant to disease enhances food production. This also helps reduce the dependence on use of fungicides and bacteriocides.
ü Resistance of the host plant is the ability to prevent the pathogen from causing disease and is determined by the genetic constitution of the host plant.
ü it is important to know about the causative organism and the mode of transmission.
ü Some of the diseases caused by fungi are rusts, e.g., brown rust of wheat, red rot of sugarcane and late blight of potato; by bacteria black rot of crucifers; and by viruses tobacco mosaic, turnip mosaic, etc.
Methods of breeding for disease resistance:
ü Breeding is carried out by the conventional breeding techniques or by mutation breeding.
The conventional method of breeding for disease resistance: 1. Hybridisation and 2. Selection.
The various sequential steps are :
1. Screening germplasm for resistance sources,
2. Hybridisation of selected parents,
3. Selection and evaluation of the hybrids and
4. Testing and release of new varieties.
Examples of some released crop varieties bred by hybridisation and selection, for disease resistance to fungi, bacteria and viral diseases are given below.
Crop Variety Resistance to diseases
Wheat Himgiri Leaf and stripe rust, hill bunt
Brassica Pusa swarnim White rust
Cauliflower Pusa Shubhra, Black rot and Curl,
Pusa Snowball K-1 blight black rot
Cowpea Pusa Komal Bacterial blight
Chilli Pusa Sadabahar Chilly mosaic virus, Tobacco mosaic virus and Leaf curl
Limitation of Conventional breeding:
ü availability of limited number of disease resistance genes that are present and identified in various crop varieties or wild relatives.
Other breeding methods for developing disease resistance varieties:
· Mutations
· Selection amongst somaclonal variants and
· Genetic engineering.
Mutation is the process by which genetic variations are created through changes in the base sequence within genes resulting in the creation of a new character or trait not found in the parental type.
Mutation breeding:
ü It is possible to induce mutations artificially through use of chemicals or radiations (like gamma radiations), and
ü Selecting and using the plants that have the desirable character as a source in breeding this process is called mutation breeding.
Examples:
1. In mung bean, resistance to yellow mosaic virus and powdery mildew were induced by mutations.
2. Resistance to yellow mosaic virus in bhindi (Abelmoschus esculentus) was transferred from a wild species and resulted in a new variety of A. esculentus called Parbhani kranti.
ü All the above examples involve sources of resistance genes that are in the same crop species, which has to be bred for disease resistance, or in a related wild species.
ü Transfer of resistance genes is achieved by sexual hybridisation between the target and the source plant followed by selection.
9.2.3 Plant Breeding for Developing Resistance to Insect Pests:
Morphological/Physiological characterstics in plants for insect resistance:
Ø Hairy leaves in several plants are associated with resistance to insect pests, e.g, resistance to jassids in cotton and cereal leaf beetle in wheat.
Ø In wheat, solid stems lead to non-preference by the stem sawfly
Biochemical characterstics in plants for insect resistance:
Ø Smooth leaved and nectar-less cotton varieties do not attract bollworms.
Ø High aspartic acid, low nitrogen and sugar content in maize leads to resistance to maize stem borers.
Breeding methods for insect pest resistance:
ü involve the same steps as those for any other agronomic trait such as yield or quality and are as discussed above.
ü Sources of resistance genes may be cultivated varieties, germplasm collections of the crop or wild relatives.
Examples: Some released crop varieties bred by hybridisation and selection, for insect pest resistance are given below.
Crop Variety Insect Pests
Brassica Pusa Gaurav Aphids
(rapeseed mustard)
Flat bean Pusa Sem 2, Jassids, aphids and
Pusa Sem 3 fruit borer
Okra (Bhindi) Pusa Sawani Shoot and Fruit borer
Pusa A-4
9.2.4 Plant Breeding for Improved Food Quality:
More than 840 million people in the world do not have adequate food to meet their daily food and nutritional requirements. A far greater number three billion people suffer from micronutrient, protein and vitamin deficiencies or `hidden hunger' because they cannot afford to buy enough fruits, vegetables, legumes, fish and meat. Diets lacking essential micronutrients particularly iron, vitamin A, iodine and zinc increase the risk for disease, reduce lifespan and reduce mental abilities.
Biofortification breeding crops with higher levels of vitamins and minerals, or higher protein and healthier fats is the most practical means to improve public health.
Breeding for improved nutritional quality is undertaken with the objectives of improving
(i) Protein content and quality;
(ii) Oil content and quality;
(iii) Vitamin content; and
(iv) Micronutrient and mineral content.
ü In 2000, maize hybrids that had twice the amount of the amino acids, lysine and tryptophan, compared to existing maize hybrids were developed.
ü Wheat variety, Atlas 66, having high protein content, has been used as a donor for improving cultivated wheat.
ü It has been possible to develop an iron-fortified rice variety containing over five times as much iron as in commonly consumed varieties.
ü The Indian Agricultural Research Institute, New Delhi has also released several vegetable crops that are rich in vitamins and minerals, e.g., vitamin A enriched carrots, spinach, pumpkin; vitamin C enriched bitter gourd, bathua, mustard, tomato; iron and calcium enriched spinach and bathua; and protein enriched beans broad, lablab, French and garden peas.
9.3 SINGLE CELL PROTEIN (SCP)
ü More than 25 per cent of human population is suffering from hunger and malnutrition.
ü One of the alternate sources of proteins for animal and human nutrition is Single Cell Protein (SCP).
ü Microbes are being grown on an industrial scale as source of good protein.
ü Microbes like Spirulina can be grown easily on materials like waste water from potato processing plants (containing starch), straw, molasses, animal manure and even sewage, to produce large quantities and can serve as food rich in protein, minerals, fats, carbohydrate and vitamins.
ü Incidentally such utilisation of waste also reduces environmental pollution.
ü It has been calculated that a 250 Kg cow produces 200 g of protein per day.
ü In the same period, 250g of a micro-organism like Methylophilus methylotrophus, because of its high rate of biomass production and growth, can be expected to produce 25 tonnes of protein.
ü The fact that mushrooms are eaten by many people and large scale mushroom culture is a growing industry makes it believable that microbes too would become acceptable as food.
9.4 TISSUE CULTURE
What is tissue culture? The process of regeneration of whole plants from explants, i.e., any part of a plant taken out and grown in a test tube, under sterile conditions in special nutrient media is called tissue culture.
Totipotency: The capacity to generate a whole plant from any cell/explant is called totipotency.
Micro- propagation: The method of producing a large number of plants in very short durations in the nutrient medium through tissue culture is called micro- propagation. The nutrient medium must provide a carbon source such as sucrose and also inorganic salts, vitamins, amino acids and growth regulators like auxins, cytokinins etc. Each of these plants will be genetically identical to the original plant from which they were grown, i.e., they are somaclones.
Examples: Many important food plants like tomato, banana, apple, etc., have been produced on commercial scale using this method.
Another important application of the method:
Ø is the recovery of healthy plants from diseased plants.
Ø Although the plant is infected with a virus, the meristem (apical and axillary) is free of virus. Hence, one can remove the meristem and grow it in vitro to obtain virus-free plants.
Ø Scientists have succeeded in culturing meristems of banana, sugarcane, potato, etc.
Somatic hybridization:
ü Scientists have even isolated single cells from plants and after digesting their cell walls have been able to isolate naked protoplasts (surrounded by plasma membranes).
ü Isolated protoplasts from two different varieties of plants each having a desirable character can be fused to get hybrid protoplasts, which can be further grown to form a new plant. These hybrids are called somatic hybrids while the process is called somatic hybridisation.
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