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Everything you need to know about ideotype breeding !
Q. 1. What is ideotype?
Ans. A biological mode which is expected to perform or behave in a predictable manner within a defined environment is known as ideotype. It is also known as ideal plant type or model plant type.
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Q. 2. Who developed the concept of plant type?
Ans. The concept of plant type was first introduced in rice breeding by Jennings in 1964.
Q. 3. Who coined the term ideotype?
Ans. The term ideotype was coined by Donald in 1968 working with wheat crop.
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Q. 4. What is crop ideotype?
Ans. A plant model which is expected to yield greater quantity of grains, fibre, oil or other useful product when developed as a cultivar is called crop ideotype.
Q. 5. Who developed the concept of crop ideotype?
Ans. The concept of crop ideotype was developed by Donald 1968 on wheat.
Q. 6. What is ideotype breeding?
Ans. A method of crop improvement which is used to enhance genetic yield potential through genetic manipulation of individual plant character is termed ideotype breeding.
Q. 7. What is harvest index?
Ans. The ratio of economic yield to the biological yield or the ratio of economic produce to total biomass is called harvest index.
Q. 8. Who coined the term harvest index?
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Ans. The term harvest index was first used by Donald in 1962.
Q. 9. What is biological yield?
Ans. Total dry matter production per plant is called biological yield or biomass.
Q. 10. What is economic yield?
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Ans. The dry weight of useful plant part such as grain yield in cereals, pulses and oilseeds and seed cotton yield in cotton is referred to as economic yield.
Q. 11. What is determinate plant type?
Ans. The plant type in which growth of apical bud is ceased after a definite period is known as determinate plant type. Usually such plants produce only one flush of flowers such as early genotypes of pigeon-pea, green-gram, black-gram, cowpea etc.
Q. 12. What are indeterminate plants?
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Ans. Plant genotypes in which apical bud grows continuously are called indeterminate plants. Such genotypes can produce second flush of flowers such as long duration genotypes of cotton and pigeon-pea.
Q. 13. What is compact plant type?
Ans. Plant types which have erect stature and have very less plant spread are known as compact plant types; also called erect plant types. Such plant types are suitable for closer spacing.
Q. 14. What is robust plant type?
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Ans. Plant genotypes which have vigorous plant growth are called robust plant types. Such genotypes are generally spreading types.
Q. 15. What is dwarf plant type?
Ans. Plant genotype having dwarf stature is called dwarf plant type.
Q. 16. What is the source of dwarfing gene in wheat?
Ans. In wheat, Norin 10 is the important source of dwarfing gene.
Q. 17. What is the source of dwarfness in rice?
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Ans. In rice, Dee-Geo-Woogen is the important source of dwarfing gene.
Q. 18. What is tall plant type?
Ans. Plant genotypes having tall stature are called tall plant types. Such genotypes are generally prone to lodging.
Q. 19. What is pyramidal plant type?
Ans. In dicots, genotypes having pyramidal shape such as in cotton refer to pyramidal plant type.
Q. 20. What are erect leaves?
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Ans. In cereals, leaves having upright position are called erect leaves. Such leaves have acute angle with the stem and also have high CO2 fixation efficiency.
Q. 21. What are drooping leaves?
Ans. in cereals, leaves having downward bending position are known as drooping leaves. Such leaves have right or obtuse angle with the stem and are considered physiologically less efficient.
Q. 22. What are tillers?
Ans. In cereals, the replica of main stem originating from the base of a plant is called tiller.
Q. 23. What is culm?
Ans. In cereals, the shoot length from first internode to the base of the spike is called culm.
Q. 24. Define physiologically efficient plants.
Ans. Plant genotypes with following characteristics are considered physiologically efficient:
(i) High CO2 fixation efficiency.
(ii) High mineral absorption efficiency.
(iii) High response to nutrients.
(iv) Low photo respiration.
(v) Photo and thermo insensitivity.
Q. 25. What is physiological crop breeding?
Ans. Genetic improvement of crop plants in relation to following physiological parameters is known as physiological crop breeding:
(i) CO2 fixation efficiency,
(ii) Nutrient uptake capacity,
(iii) High harvest index,
(iv) Reduction in photo-respiration and transpiration.
Q. 26. What is synchronous maturity?
Ans. The maturity of all fruits of a plant at the same time is known as synchronous maturity. Such trait is desirable for harvesting by machine.
Q. 27. What is idiotype?
Ans. Morphological features of the chromosomes of a particular plant species refers to idiotype.
Q. 28. What are C3 plants?
Ans. Plant species producing three carbon compounds (phosphoglyceric acid) as the first stable substance during photosynthesis are called C3 plants. C3 plants are physiologically lesser efficient than C4 plants.
Q. 29. What are examples of C3 plants?
Ans. Majority of crop plants are C3. Examples of C3 plants include rice, wheat, barley, pulses, oil seeds etc.
Q. 30. What are C4 plants?
Ans. Those plant species which produce four carbon compounds (oxaloacetic acid) as the first stable product of photosynthesis are called C4 plants. Physiologically C4 plants are more efficient than C3 plants.
Q. 31. Cite examples of C4 plants.
Ans. C4 plants include Maize, Sorghum, Sugarcane and Amaranthus.
Q. 32. Who first proposed ideal plant type of maize?
Ans. In maize, ideal plant type was first suggested by Mock and Pearce in 1975.
Q. 33. Who first suggested ideal plant type of six-rowed barley?
Ans. In six-rowed barley, ideal plant type was first suggested by Rasmusson in 1987.
Q. 34. Who proposed ideal plant type of cotton for irrigated conditions?
Ans. The ideal plant type of American and Desi cottons for irrigated conditions was proposed by Singh et.al (1974).
Q. 35. Who proposed ideal plant type of cotton for rainfed conditions?
Ans. For rainfed conditions, ideal plant type of upland and arboreum cottons was proposed by Singh and Narayanan in 1993.
Q. 36. Who proposed ideotype of Brassica?
Ans. Ideotype of Brassica was proposed by Bhargava et al in 1984.
Q. 37. Who proposed ideotype of wheat for rainfed conditions?
Ans. In India, ideotype of wheat for rainfed conditions was proposed by R.D. Asana.
Q. 38. Who proposed ideotype of Brassica napus for rainfed conditions?
Ans. Ideotype of Brassica napus for rainfed conditions was proposed by Thurling in 1991.
Q. 39. What are main features of ideotype breeding?
Ans. Main features of ideotype breeding are given below:
(i) Emphasis is given on individual trait which enhances the yield.
(ii) It includes morphological and physiological traits.
(iii) It exploits physiological variation.
(iv) It involves inter-disciplining approach.
(v) It is a slow method of cultivar development.
(vi) Selection is focused a yield enhancing traits.
(vii) Values of each character are decided in advance.
Q. 40. What are main features of wheat ideotype?
Ans. Main features of wheat ideotype are listed below:
(i) Short and strong stem.
(ii) Erect leaves.
(iii) Few small leaves.
(iv) Larger and erect ear.
(v) Presence of awns.
(vi) A single culm.
Q. 41. What are main features of rice ideotype?
Ans. Main features of rice ideotype as given below:
(i) Semi dwarf stature.
(ii) High tillering capacity,
(iii) Short, erect, thick and highly angled leaves.
Q. 42. What are main features of maize ideotype?
Ans. In maize, main features of ideal plant type are given below:
(i) Low tillers.
(ii) Large cobs.
(iii) Engled leaves.
Q. 43. What are the factors affecting ideotype?
Ans. Ideotype is affected by following factors:
(i) The crop species,
(ii) Type of cultivation or cultivation practices,
(iii) Socioeconomic conditions of farmers,
(iv) Economic use.
(v) Market requirements etc.
Q. 44. What steps are involved in ideotype breeding?
Ans. Ideotype breeding consists of following steps:
(i) Development of conceptual model.
(ii) Selection of base material from germplasm.
(iii) Incorporation of desirable traits.
(iv) Selection of desirable plant type.
Q. 45. In which crops ideotype breeding has been rewarding?
Ans. Ideotype breeding has been rewarding in cereals (wheat and rice) and millets (Sorghum and pearl millet).
Q. 46. What is the plant type suggested by M.S. Swaminathan?
Ans. M.S. Swaminathan has listed the following desirable attributes of crop ideotypes with special reference to multiple cropping in the tropics and sub-tropics.
They are:
(i) Superior population performance.
(ii) High productivity per day.
(iii) High photosynthetic ability.
(iv) Low photorespiration.
(v) Photo and thermo insensitivity.
(vi) High response to nutrients.
(vii) High productivity per unit of water.
(viii) Multiple resistances to insects and diseases.
(ix) Better protein quantity and quality.
(x) Crop canopy that can retain and fix a maximum of CO2.
(xi) Stability to mechanization.
Q. 47. What are advantages of ideotype breeding?
Ans. It provides solution to several problems at a time like disease, insects and lodging resistance, maturity duration, yield and quality by combining desirable genes for these traits from different sources into a single genotype.
Q. 48. What are demerits of ideotype breeding?
Ans. Ideotype breeding has some limitations or demerits. Incorporation of several morphological, physiological and resistance traits from different sources into a single genotype is a difficult task. Sometimes, combining of some characters is not possible due to tight linkage between desirable and undesirable characters. Presence of such linkage hinders the progress of ideotype breeding. Moreover, it is a slow method of cultivar development.
Q. 49. What are differences between traditional breeding and ideotype breeding?
Ans. Main differences between traditional breeding and ideotype breeding are presented below in Table 30.1:
