This article is on the Strategies for Enhancement in Food Production class 12 Notes of Biology. The notes on Strategies for Enhancement in Food Production of class 12 biology have been prepared with great care keeping in mind the effectiveness of it for the students. This article provides the revision notes of the Strategies for Enhancement in Food Production chapter of Class 12 for the students so that they can give a quick glance of the chapter.
Strategies for Enhancement in Food Production
It is the rearing of animals by man for profit. Commonly reared animals include livestock like cows, buffaloes, pigs, horses, cattle, sheep, camels, goats, etc. it also includes poultry farming and fishery. Fisheries include rearing, catching and selling of fish, molluscs and crustaceans (prawns, crabs, etc.).
Estimates predict that more than 70 percent of the world’s livestock population is in India and China. However, their contribution to the world’s produce is only 25 percent. Thus the productivity per unit is very low. Hence, it is essential to think about the adoption usage of new technologies and practices to improve the yield and profitability.
Important Factors Necessary to Enhance the Yield from Animals
1. Suitable breed.
2. Clean shelter.
3.Good quality of appropriate food.
4. Vaccination and other relevant medical care
Breeding is important from the point of view of increasing the output from animals. It allows the breeder to have animals with a desired set of characteristics.
It is breeding between animals of the same breed. It is the mating of closely related individuals within the same breed for 4-6 generations.
The cow or buffalo that yields more milk per lactation is called a superior female. Whereas the bull which gives rise to superior progeny as compared to those of other males is called a superior male. Superior males and superior females of the same breed are identified and mated in pairs. The progeny obtained are evaluated and superior males and females among them are marked for further mating.
Inbreeding increases homozygosity. It is thus used for generating pure lines. Inbreeding tends to expose harmful recessive genes. The organisms with these genes can then be taken out of the breeding program. Thus inbreeding can help to increase productivity. In some cases, continued inbreeding, (especially between closely related individuals) reduces fertility and even productivity. This is called Inbreeding depression. As the remedy for this is to allow mating with unrelated superior animals of the same breed.
The breeding of the unrelated animals, which may be between individuals of the same breed, having no common ancestors or of different breeds or of different species is called out-breeding.
The practice of mating of animals having no common ancestors on either side of their pedigree up to 4-6 generations within the same breed is called out-crossing. The offspring of such a mating is known as an out-cross. A single outcross often helps to overcome inbreeding depression. It also improves milk productivity and growth.
Superior males of one breed are mated with superior females of another. Cross-breeding allows the desirable qualities of two different breeds to be combined. The progeny hybrid animals may themselves be used for commercial production.
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. 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.
3. Interspecific Hybridization
A male and female 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., Mules (Offspring of a male donkey and a female horse) are sturdier and hardier than their parental species.
Poultry farming is the rearing of domesticated birds like fowl, chicken and ducks, turkey and geese. Birds contain more protein compared to fats. Eggs laid by some birds are also consumed. Poultry farming requires less space and investment. The birds are fed with cereals, millets oil cakes, fish and meat meal, minerals and green vegetables, fish silage, protein concentrate etc.
Maintenance of honey bee colonies in hives is called apiculture. Apiculture can provide us with honey. Bees pollinate our crops (E.g. sunflower) and hence are beneficial for farmers too. Bees are social animals and show the division of labour in their colonies. Other products harvested from the beehive include royal jelly, beeswax, beeglue etc.
Important Species of Honey – Bees
1. Apis dorsata (Rock bee)
It is also named as saarang bee. It is a large sized and produces large quantities of honey. But due to its aggressiveness and migratory behaviour, it is not suitable for apiculture.
2. Apis indica (Indian Mona-bee)
It yields about 3- 4 kg of honey per hive. It is not aggressive and hence is suitable for apiculture.
3. Apis florea (Bhiringa – bee)
It is small and timid but yields only 250 gm of honey per hive. Hence it is unsuitable for commercial apiculture.
4. Apis mellifra (European bee)
It is mild and produces more honey than Mona-bee. Hence it is important from the point of view of apiculture.
Artificial hives are used so that the extracting of products becomes simpler. Protective clothing is used to avoid stings. Experienced bee-keeps may not use gloves as they hinder delicate manipulations. Smokers are used as defence mechanisms. Smoke calms bees down and also masks the scent of their signalling mechanisms.
Important focuses for effective Bee Keeping
It does not require high investment and is not labour intensive. The location of an apiary should be near an orchard or a flower garden. The person should possess a knowledge of what type of hive can suit the species of the bees he has chosen for apiculture. He/She should be able to catch a swarm of bees and transfer them into the hive. The person should also possess certain skills required to extract honey and other products from the hive.
It should be understood that along with better management, it is highly essential to use improved varieties of plants if the output is to be drastically improved. Purposeful manipulation of plant species in order to create desired plant varieties that have a better yield, high tolerance to stress-related factors and enhanced disease resistance is called plant breeding.
Desirable characters as such include better quantity and quality of yield, tolerance to drought, salinity, high/low temperatures, disease resistance, pest resistance etc. Generally, pure lines with desirable characters are crossed. Artificial selection is employed to obtain the desired variety. Genetic tools are also being employed to achieve the same.
Steps Involved in Plant Breeding
1. Variability and Parent Selection
Variability is the basic necessity as unless there is no variability, there can be no ‘desirable characters’ which can be used to create an enhanced variety. The entire collection of plants and/or seeds having all the diverse alleles for all genes in a given plant is called germplasm collection. Plants possessing one or more of the desired characters are selected as parents.
2. Pure line Generation
Pure lines homozygous for one or more of the desired characters are generated whenever possible. Understandably, the use of pure lines highly increases the probability of incorporation of the desired characters in the progeny.
The parental plants are crossed. As crop plants possess several genes it should be noted that the frequency of occurrence of progeny possessing a combination of the desired genes from both the parents will be very low.
4. Selection and Generation of Purelines
The progeny has to be tested for the possession of the required genes/traits. The desired progeny then has to be self-pollinated to generate pure lines so that the traits are homozygous (not eliminated in the subsequent generations).
5. Testing and Launch in the Market
The new plant variety is generally grown in test farms to analyse its performance outside the experimental set up in comparison to cultivars already in use. Following positive results, it is marketed. Otherwise, it may have to undergo improvement. The cultivar is also tested in actual farms located in different regions of the country.
The Green Revolution
It was the research, development and actual implementation of reforms in agriculture that led to a significant increase in yield. In India implementation began in the 60s. Semi-dwarf varieties of rice and wheat were grown. The yield increased tremendously. Sonalika and Kalyan Sona were high yieldings and disease resistant varieties of wheat which were introduced all over the wheat-growing belt of India.
Rice varieties derived from IR-8 (Developed at International Rice Research Institute, Philippines) and Taichung Native-1 (Taiwan) were used. Later better-yielding semi-dwarf varieties Jaya and Ratna were developed in India. Saccharum barberi variety of sugarcane was traditionally grown in North India. It had poor sugar content and yield. Saccharum officinarum which was being grown in South India had thicker stems and higher sugar content but did not grow well in North India. These two species were successfully crossed to get varieties with desired characters that could grow well in North India too. Hybrid varieties of maize, jowar and bajra having high draught resistance and producing more grains were developed.
Single Cell Protein (SCP)
The present quantity of agricultural production is not enough to cater the increasing needs. More than 25% of the human population is suffering from hunger and malnutrition. It takes 3-10 kg of grain to produce 1 kg of meat by animal farming. Thus it is essential to also explore alternative sources of food (other than plants and meat). One of them is single cell protein or SCP.
Bacteria like spirulina can be grown on wastes from some industries. They can be consumed as food containing proteins, carbohydrates, fats etc. The advantage of this approach is the high biomass production by the bacteria. An equivalent mass of spirulina can produce several times more proteins than a mammal like cow. Many people are unwilling to consume SCP as food but it can be used as animal feed with relative ease.
The growth of plant or animal tissues in the culture medium is called tissue culture. Plant tissue culture is extensively used in research aimed at enhancing food production. Plants possess an ability to regenerate a whole plant from a single cell or explant. This ability is called totipotency. The explant (any part of the plant) is kept in a nutrient medium in sterile conditions. The medium should have a carbon source, some specific salts, vitamins, some amino acids, auxins and similar growth regulatory substances.
A large number of plants can be generated in a very short period of time using plant tissue culture. This is called micropropagation. Each of the plants is clones of the original plant. Bananas, apples etc. have been produced on a commercial scale by using plant tissue culture. A plant obtained from meristem culture is free from virus or any other infection.
The cell wall of plants can be digested to form protoplast surrounded by the plasma membrane. These protoplasts can be fused to produce somatic hybrids. Somatic hybridization can be used to obtain hybrids that are not possible by sexual reproduction. (E.g. tomato-potato hybrid, rice-carrot hybrid etc.) Anther culture can be used to obtain haploid plants. These plants can be used for crossing or in research. Embryo culture can be used to grow embryos that may not survive ordinarily.
This article has tried to highlight all the important points of Strategies for Enhancement in Food Production in the form of notes for class 12 students in order to understand the basic concepts of the chapter. The notes on Strategies for Enhancement in Food Production have not only been prepared for class 12 but also for the different competitive exams such as iit jee, neet, etc.