Strategies for Enhancement in Food Production — NEET Notes

The food mandate — why this chapter exists

India hosts more than 70 per cent of the world's livestock population alongside China, yet contributes only 25 per cent of world farm produce. The arithmetic is brutal: very high stock, very low productivity per unit. With a population that no longer pauses, the country cannot afford the gap. Biological principles applied to animal husbandry and plant breeding have already once rescued India from grain dependence — the Green Revolution of the 1960s lifted wheat production from 11 million tonnes to 75 million tonnes between 1960 and 2000, and rice from 35 million tonnes to 89.5 million tonnes. Newer techniques — embryo transfer, tissue culture, biofortification, single-cell protein — are positioned to play the same role again. This chapter assembles the toolkit.

"More than 840 million people in the world do not have adequate food. A far greater number — three billion — suffer from hidden hunger: deficiencies of iron, vitamin A, iodine, zinc."

The food-security mandate behind biofortification — NCERT 2019

Animal husbandry — the working definitions

Animal husbandry is the agricultural practice of breeding and raising livestock — buffaloes, cows, pigs, horses, cattle, sheep, camels, goats — that are useful to humans. Extended, it covers poultry farming (chicken, ducks, turkey, geese) and fisheries (fish, molluscs, crustaceans), and reaches as far as bee-keeping and sericulture. Each branch shares a core management discipline: select disease-free, high-yielding breeds; provide hygienic housing, clean water and scientifically formulated fodder; mechanise milking, storage, and transport where possible to minimise human contact with the produce; and keep detailed records with periodic veterinary inspection.

Two specialised branches deserve separate framing. Apiculture — bee-keeping — is the maintenance of hives of honeybees for honey production. The most common reared species is Apis indica. Honey is a high-nutritive-value food and a recognised ingredient in indigenous medicine; beeswax is used in cosmetics and polishes. Critically, bees are the pollinators of many crop species — sunflower, Brassica, apple, pear — so keeping beehives in a flowering crop field improves both honey yield and crop yield via better pollination. Bee-keeping is not labour-intensive but does demand knowledge of bee biology, hive location, swarm hiving, season-by-season management, and clean handling of honey and beeswax.

Fisheries cover catching, processing and selling of fish, shellfish and other aquatic animals (prawns, crabs, lobster, edible oyster). Common freshwater fishes include Catla, Rohu and common carp; common marine fishes include Hilsa, Sardine, Mackerel and Pomfret. Through aquaculture (controlled growing of aquatic plants and animals, fresh-water and marine) and pisciculture (specifically fish-farming), India has driven a "Blue Revolution" along the same lines as the Green Revolution — providing income and employment to millions of coastal-state farmers.

Animal breeding — inbreeding, outbreeding, MOET

A breed is a group of animals related by descent and similar in most characters — general appearance, features, size, configuration. Animal breeding aims at increasing yield and improving desirable qualities. Two broad strategies operate, and NEET tests the distinction directly (the 2019 paper asked an incorrect-statement question on inbreeding, the 2020 paper asked about Hisardale sheep, and the 2017 paper asked how purelines in cattle are obtained — all answered by this section).

Inbreeding is the mating of more closely related individuals within the same breed for 4–6 generations. Superior males and superior females of the same breed are identified and mated; superior progeny are then identified and mated further. A superior female cow or buffalo is one that produces more milk per lactation; a superior bull is one whose progeny outperform those of other bulls. The strategy mirrors Mendel's pureline development in peas: inbreeding increases homozygosity, evolves purelines, exposes harmful recessives that selection can eliminate, and accumulates superior alleles. The catch is inbreeding depression — continued close inbreeding reduces fertility and even productivity. The escape hatch is to mate selected animals of the inbred population with unrelated superior animals of the same breed, restoring fertility and yield.

Outbreeding is the breeding of unrelated animals. Three sub-types exist: out-crossing (same breed but no common ancestor up to 4–6 generations — the offspring is an out-cross, and a single such cross often reverses inbreeding depression); cross-breeding (superior males of one breed mated with superior females of another, combining the desirable qualities of both — the textbook example is Hisardale, a new breed of sheep developed in Punjab by crossing Bikaneri ewes with Marino rams); and interspecific hybridisation (two different species — the mule, from a male donkey × female horse, is the standing example).

Two technologies amplify the breeder's reach. Artificial insemination collects semen from a chosen male, freezes and transports it, and inseminates the female. The single ejaculate can fertilise many females, semen survives freezing, and a champion bull can be used across continents and across years. Multiple Ovulation Embryo Transfer Technology (MOET) takes the female side of the equation: a cow is administered FSH-like hormones to induce super-ovulation — instead of one egg per cycle she produces 6–8. She is then mated with an elite bull or artificially inseminated. The fertilised eggs at the 8–32 cell stage are recovered non-surgically and transferred to surrogate mothers, while the genetic mother is freed up for another round. MOET has been demonstrated in cattle, sheep, rabbits, buffaloes and mares — and is the route by which high milk-yielding females and lean-meat-yielding bulls are scaled up in short timeframes.

Plant breeding — the six-step pipeline

Traditional farming can only yield a limited biomass; better management and more acreage take that biomass up only a little further. Plant breeding is the purposeful manipulation of plant species to create desired plant types that are better suited for cultivation, give better yields and are disease resistant. Conventional plant breeding has been practiced for 9,000–11,000 years; classical plant breeding involves crossing or hybridisation of pure lines followed by artificial selection. With molecular biology and tissue culture, the toolkit has widened — but the workflow remains the same five-to-six-step pipeline, and every NEET-relevant variety (Himgiri wheat, Pusa Swarnim mustard, Saccharum officinarum × barberi sugarcane, Jaya/Ratna rice) came out of this pipeline.

Two textbook outcomes anchor this pipeline. Wheat and rice in the Green Revolution: Norman E. Borlaug, at CIMMYT in Mexico, developed semi-dwarf wheat; varieties Sonalika and Kalyan Sona were introduced across India in 1963, high-yielding and disease-resistant. Semi-dwarf rice was derived from IR-8 (IRRI, Philippines) and Taichung Native-1 (Taiwan) and released in 1966; Jaya and Ratna followed as improved Indian-developed lines. Sugarcane: Saccharum barberi (north India — poor sugar, low yield) was crossed with Saccharum officinarum (south India — thick stems, high sugar, but did not grow well in the north). The cross combined high yield, thick stems, high sugar, and ability to grow in northern sugarcane belts. Millets: hybrid maize, jowar and bajra are now widely cultivated, with several water-stress-resistant high-yielding varieties.

Four breeding objectives — what breeders target

Plant breeders work towards four primary objectives. NEET has tested each one — biofortification was a direct ask in 2022, disease-resistance varieties appear in match-the-following questions, and pest-resistance examples surface in straight-recall stems. Memorise at least one example variety per objective.

Plant breeding for disease resistance

Fungal, bacterial and viral pathogens cut yields by 20–30 per cent, sometimes wiping out entire crops. Examples: fungal brown rust of wheat, red rot of sugarcane, late blight of potato; bacterial black rot of crucifers; viral tobacco mosaic, turnip mosaic. Breeding resistant cultivars reduces dependence on fungicides and bacteriocides, and is more sustainable. Resistance is determined by the genetic constitution of the host — so the breeder's task is to identify a resistance gene (in the cultivated species or a wild relative) and move it into the high-yielding cultivar via hybridisation and selection. The standard pipeline applies: screen germplasm → hybridise selected parents → select & evaluate hybrids → test & release.

The named varieties to memorise: Himgiri (wheat — leaf rust, stripe rust, hill bunt), Pusa Swarnim / Karan rai (Brassica — white rust), Pusa Shubhra and Pusa Snowball K-1 (cauliflower — black rot and curl blight black rot), Pusa Komal (cowpea — bacterial blight), Pusa Sadabahar (chilli — chilli mosaic, tobacco mosaic, leaf curl). When the cultivated species offers no resistance gene, mutation breeding kicks in: mutations are induced artificially through chemicals or gamma radiation, and the resistant plants are selected. Mung bean resistance to yellow mosaic virus and powdery mildew was developed by mutation breeding. Where a wild relative has the gene, sexual hybridisation transfers it — yellow mosaic virus resistance in bhindi (Abelmoschus esculentus) was transferred from a wild species, giving rise to Parbhani Kranti.

Plant breeding for insect-pest resistance

Insect attack causes losses comparable to disease. Resistance is built into a host plant through one of three routes — morphological (hairy leaves resist jassids in cotton and cereal leaf beetle in wheat; solid stems make wheat non-preferred by the stem sawfly; smooth, nectar-less cotton does not attract bollworms); biochemical (high aspartic acid + low nitrogen + low sugar in maize confers resistance to maize stem borers); or physiological. The breeding pipeline is again standard: source resistance from cultivars, germplasm, or wild relatives → cross → select → release. The named pest-resistant varieties: Pusa Gaurav (Brassica/rapeseed mustard — aphids), Pusa Sem 2 and Pusa Sem 3 (flat bean — jassids, aphids, fruit borer), Pusa Sawani and Pusa A-4 (okra/bhindi — shoot and fruit borer).

Biofortification — breeding for food quality

This is the most directly NEET-tested objective in the chapter — the 2022 paper asked, in a one-line direct stem, "Breeding crops with higher levels of vitamins and minerals or higher proteins and healthier fats is called ____?" The answer is biofortification. The 2021 paper asked which is not an objective of biofortification, with disease resistance as the trap option. Memorise the four objectives and rule out anything outside them.

The four objectives of biofortification are: (i) protein content and quality; (ii) oil content and quality; (iii) vitamin content; and (iv) micronutrient and mineral content. Examples to memorise — in 2000, maize hybrids with twice the lysine and tryptophan of conventional varieties were developed. Atlas 66 wheat is a high-protein donor used to improve cultivated wheat. Iron-fortified rice contains over five times the iron of common rice. The Indian Agricultural Research Institute (IARI), New Delhi, has released vitamin-A-enriched carrots, spinach, pumpkin; vitamin-C-enriched bitter gourd, bathua, mustard, tomato; iron- and calcium-enriched spinach and bathua; and protein-enriched broad bean, lablab, French bean, garden peas. A separate brief in the chapter mentions Brassica BHU-1 as a protein-rich biofortified variety in Indian breeding circles.

Single Cell Protein (SCP)

Conventional cereal-pulse-vegetable production may not keep pace with population growth, especially as diets shift from grain to meat: it takes 3–10 kg of grain to produce 1 kg of meat (a consequence of trophic-level energy loss). More than 25 per cent of the human population suffers hunger or malnutrition. Single Cell Protein is one of the alternate protein sources — microbes grown industrially as a source of protein-rich biomass for human and animal nutrition.

Two organisms appear in NCERT and remain the canonical NEET examples. Spirulina, a blue-green alga, can be grown on waste water from potato-processing plants (containing starch), straw, molasses, animal manure, and even sewage — producing large quantities of biomass that is rich in protein, minerals, fats, carbohydrate, and vitamins. The bacterium Methylophilus methylotrophus, on account of its high biomass-production rate, can be expected to produce 25 tonnes of protein. Edible mushrooms are widely consumed and large-scale mushroom culture is a growing industry, making it plausible that microscopic fungi will become acceptable as food. SCP delivers two benefits — protein production and waste recycling (it reduces environmental pollution by consuming industrial and agricultural waste).

Tissue culture & totipotency

Traditional breeding could not keep pace with demand for fast, efficient crop improvement. Tissue culture — developed in the 1950s — was the answer. Scientists discovered that whole plants could be regenerated from explants (any part of a plant taken out and grown in a test tube under sterile conditions in special nutrient media). The capacity of any cell or explant to regenerate into a whole plant is called totipotency. This is the conceptual foundation of all plant tissue culture.

The nutrient medium is non-negotiable. It must supply: a carbon source like sucrose; inorganic salts; vitamins; amino acids; and growth regulators — particularly auxins and cytokinins. Under sterile conditions with the right ratio of these hormones, the explant first proliferates as an unorganised callus, which is then induced to differentiate into shoot and root systems and regenerate a whole plant.

The technique enables micropropagation — production of thousands of plants in very short durations from a single explant. Every plant produced is genetically identical to the original parent; these are called somaclones. Commercial micropropagation has been demonstrated in tomato, banana, apple, and many other food crops. A separate application of tissue culture is recovery of virus-free plants from infected stock: even when the whole plant is infected with a virus, the meristem (apical and axillary) remains virus-free. Excising the meristem and growing it in vitro yields virus-free plants — a strategy successfully applied to banana, sugarcane, and potato.

Somatic hybridisation — protoplast fusion & pomato

Tissue culture's most exotic offspring is the somatic hybrid. Scientists have isolated single cells from plants and, after digesting away the cell wall with enzymes, recovered naked protoplasts bounded only by the plasma membrane. Isolated protoplasts from two different varieties — each carrying a desirable character — are then induced to fuse. The fused protoplast, a hybrid protoplast, is grown into a new plant. This is somatic hybridisation; the product is a somatic hybrid. The most famous somatic hybrid is pomato — a fusion between a tomato protoplast and a potato protoplast. Pomato was successfully generated, but it did not exhibit the desired combination of characters and never reached commercial cultivation.

The 2021 NEET paper tested this whole region as a four-way match: protoplast fusion ↔ pomato; plant tissue culture ↔ totipotency; meristem culture ↔ virus-free plants; micropropagation ↔ somaclones. Memorise the four pairings as a unit.