You are a Botanist working in the area of plant breeding. Describe the various steps that you will undertake to release a new variety.
Plant breeding programmes are carried out in a systematic way world wide-in government institutions and commercial companies.
The main steps in breeding a new genetic variety of a crop are
(i) Collection of Variability Genetic variability is the root of any breeding programme. In many crops pre-existing genetic variability is available from wild relatives of the crop.
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.
The entire collection (of plants/seeds) having all the diverse alleles for all genes in a given crop is called germplasm collection.
(ii) Evaluation and Selection of Parents The germplasm is evaluated so as to identify plants with desirable combination of 'characters. The selected plants are multiplied and used in the process of hybridisation. Purelines are created wherever desirable and possible.
(iii) Cross Hybridisation Among the Selected Parents The desired characters have very often to be combined from two different plants (parents), e.g., high protein quality of one parent may need to be combined with disease resistance from another parent.
This is possible by cross hybridising the two parents to produce hybrids that genetically combine the desired characters in one plant. This is a very time-consuming and tedious process since the pollen grains from the desirable plant chosen as male parent have to be collected and placed on the stigma of the flowers selected as female parent.
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 This step consists of selecting, among the progeny of the hybrids, those plants that have the desired character combination. The selection process is crucial to the success of the breeding objective and requires careful scientific evaluation of the progeny.
This step yields plants that are superior to both of the parents (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 The newly selected lines are evaluated for their yield and other agronomic traits of quality, disease resistance, etc.
This evaluation is done by growing these in the research fields and recording their performance under ideal fertiliser application, irrigation and other crop management practices.
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 when the crop is usually grown.
The material is evaluated in comparison to the best available local crop. After evaluation the variety can be relased for the farmers.
(a) The shift from grain to meat diets creates more demands for cereals. Why?
(b) A 250 kg cow produces 200 g of protein per day but 250 g of Methylophillus methylotrophus can produce 25 tonnes of protein. Name this emerging area of research. Explain its benefits.
(a) The shift from grain to meat diets creates more demand for cereals as it takes $3-10 \mathrm{~kg}$ of grain to produce 1 kg of meat by animal farming.
(b) This research is related to single cell protein.
Microbes are being grown on an industrial scale as a source of good protein. Microbes like Spirulina can be grown easily on materials like wastewater 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.
Such utilisation also reduces the environmental pollution.
What are the advantages of tissue culture methods over conventional method of plant breeding in crop improvement programmes?
As traditional (conventional) breeding methods failed to keep pace with demand and to sufficiently provide fast and efficient systems for crop improvement, another technology called tissue culture developed.
The advantages of tissue culture over conventional breeding are as follows
(i) It can be used to produce large number of plantlets within a short period by micropropagation.
(ii) All cells in the culture are derived from a single explant by mitotic division, therefore all have the similar genotype and constitute a clone.
(iii) Tolerance to stress can be obtained by providing pollutants, toxins, salts, etc., in culture medium in increasing dosage. The surviving healthy cells are selected for raising resistant plants.
(iv) Virus free plantlets can be obtained by meristem culture.
(v) Embryos which do not survive inside seeds can be grown by tissue culture to form new plants.
'Modern methods of breeding animals and plants can alleviate the global food shortage'. Comment on the statement and give suitable examples.
With ever increasing population of the world, enhancement of food production is a major necessity. Modern biological principles as applied to animal husbandry and plant breeding have a major role in our efforts to increase food production. These modern techniques include embryo transfer technology and tissue culture techniques.
Multiple Ovulation Embryo Transfer Technology (MOET) is a programme for herd improvement in animals like cattle, sheep, rabbits, buffaloes, mares, etc.
High milk-yielding breeds of female are bred with high quality meat-yielding (meat with less lipid) bulls to increase herd size. It ensures good quality of progeny. It is also economic and time saving process to obtain the desirable progeny.
The procedure for MOET is as follows
(i) A cow is administered hormones with FSH-like activity to induce follicular maturation and super-ovulation.
(ii) The cow produces 6-8 eggs instead of one egg produced normally.
(iii) It is now, either mated with an elite bull or artificial insemination is carried out.
(iv) When the fertilised eggs attain 8-32 cells stage, they are non-surgically removed and transferred to a surrogate mother.
(v) The genetic mother can now be again super ovulated.
Modern methods in plant breeding involves following
(i) Tissue culture is an in vitro technique of regeneration of a whole plant from any part of a plant (explant) by growing it on culture medium under aseptic conditions.
(ii) Biofortification is the method for developing crops with higher levels of vitamins, minerals, proteins and healthier fats to improve public health.
(iii) Single cell protein is an alternative protein source for animal and human nutrition from certain beneficial microorganisms like Spirulina.
Does apiculture offer multiple advantages to farmers? List its advantages if it is located near a place of commercial flower cultivation.
Yes, apiculture offers many advantages to farmers such as
(i) Honey produced by honeybees is a food of high nutritive value.
(ii) It is used in the indigenous system of medicine.
(iii) Honeybee also produces beeswax, which is used in the preparation of cosmetics and polishes of various kinds.
If apiculture is done near a place of commercial flower cultivation it offers several advantages. Bees are the pollinators of many crop species such as sunflower, Brassica, apple and pear. Keeping beehives in crop fields during flowering period
(i) Increases pollination efficiency.
(ii) Improves the yield which is beneficial both from the point of view of crop yield and honey yield.