CBSE Class 12 Biology Revision Notes Chapter 9 - strategies for enhancement in food production
REVISION NOTES FOR CBSE CLASS 12 BIOLOGY CHAPTER 9
Improvement in food production: Plant breeding, tissue culture, single cell protein, Biofortification, Apiculture and Animal husbandry.
Explant: Any part of plant excised from its original location and used for tissue culture.
Germplasm Collection: The entire collection having all the diverse alleles for all the genes in a given crop.
Totipotency: The ability or capacity of a cell or explant to give rise to a complete plant is called totipotency.
Inbreeding Inbreeding: refers to the mating of more closely related individuals within the same breed for 4-6 generations.
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 (interspecific hybridisation).
Inbreeding depression: Continued close inbreeding decreases the fertility and productivity.
• Out crossing: 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 (interspecific hybridisation)
• Cross breeding: The practice of mating of animals of same breed but have no common ancestor on either side of pedigree upto 4-6 generations. A single outcross helps to overcome the inbreeding depression.
The Multiple Ovulation Embryo Transfer (MOET): Technology can improve the success rate of fertilisation. In this procedure, a cow is given hormonal treatment (FSH), so that more than one ova/eggs (6-8) are produced per cycle. After mating or artificial insemination the embryos at 8-32 celled stage are transferred to different surrogate mother cows. This technology has been successfully used for cattle, sheep, rabbit, mares and buffaloes.
ABBREVIATIONS
ET - Embryo Transfer
IARI - Indian Agricultural Research Institute
IRRI - International Rice Research Institute
ICAR - Indian Council of Agriculture Research
MOET - Multiple Ovulation Embryo Transfer Technology
NDRI - National Dairy Research Institute
BEE-KEEPING
Apiculture or Bee-keeping is the maintenance of hives of honeybees for the production of honey. Apiculture is beneficial for farmers in many ways. Honey bee also produces beewax which is used in industries, such as in preparation of cosmetics and polishes of various kinds. If Bee-keeping is practiced in any area the commercial flowers are cultivated, it will be beneficial in the following ways.
(i) Bees are pollinators of many crop species including flowering crops such as sunflower.
(ii) It improves the honey yield, because honeybees collect the nectar from flowers for making honey. Apis indica is the most common species which is reared in India.
MANAGEMENT OF FISHERIES :
(i) Fresh water fishes: Catla, Rohu, Common Carp
(ii) Marine fishes: Hilsa, Sardines, Mackerel and Pomfrets etc.
Aquaculture and Pisciculture: The production of useful aquatic plants and animals (both freshwater and marine) like fishes, prawns, lobsters and edible oysters is called aquaculture while the production of fishes only is called pisciculture.
Blue Revolution: Increase in fish production due to utilisation of m technology.
Plant breeding : Manipulation of plant species to create plants with desn qualities like high yield and disease resistance.
MAIN STEPS IN BREEDING A NEW GENETIC VARIETY OF CROP:
(i) Germ-plasm collection or collection of variability
(ii) Evaluation and selection of parents
(iii) Cross breeding or hybridisation of selected parents.
(iv) Selection and testing of superior recombinants
(v) Testing, release and commercialisation of new cultivars.
HIGH YIELDING VARIETIES:
(i) Wheat: Sonalika, Kalyan Sona.
(ii) Rice: IR-8, Jaya, Ratna, Padma
(iii) Sugarcane :
(i) Viral: Tobacco mosaic, turnip mosaic..
(ii) Bacterial : Black rot of crucifers, blight of rice.
(iii) Fungal : Rust of wheat, red rot of sug late blight of potato.
Mutation : Sudden inheritable change in the characters of an organism to change in the sequence of bases in the gene(s).
¶ Mutation results in a new character or trait, not found in the parental type.
¶ It can also be induced by using mutagens like gamma radiations.
¶ Such plant materials are used as such or used for breeding new varieties.
¶ Mung bean resistance to yellow mosaic virus and powdery mildew.
Mutational breeding : When mutations are artificially induced and such plants with desirable traits are selected. This process is called mutational breeding.
Steps of mutational breeding: Mutations are induced by physical (low or high temperature) chemical (hydrazines, nitrous acid) or radiations (x-rays).
¶ Mutants are tested for the desired trait
¶ If desired trait obtained then they are used to transfer this trait to desirable varieties e.g. mung bean obtained resistant to yellow mosaic virus.
BIOFORTIFICATION :
Biofortification is the plant breeding programme designed to increase vitamins, minerals, higher proteins and healthier fat content in crops. This programme improves the quality of food products. It is required to prevent hidden hunger. Some of the examples of fortified crops are :
(i) New hybrid of maize : twice the amount of amino acid lysine and tryptophan.
(ii) Wheat: Atlas 66, having a high protein content
(iii) Rice : 5 times iron than the normal amount. IARI Delhi has released
Single Cell Protein (SCP): Protein Rich food obtained from microbes such as algae, bacteria, yeast e.g. Methylophilus methylotrophus, Spirulina, Mushrooms.
It is a quick method of protein production because the growth rate of microbes is enormous. several crops which are rich in vitamins and minerals. Consumption of
such biofortified food will vastly improve the public health.
Tissue Culture: In this method any vegetative part of plant such as stem or meristem is placed in a nutrient medium containing sugar, salt, vitan. and growth regulator under optimal condition. This gives rise to plants identical to parent plant.
This method is used for micropropagation as thousands of plants which are genetically identical to parent plant (Somaclones) can be obtained in a short duration.
Comments
Post a Comment