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Everything you need to know about breeding for drought and salinity resistance !
Q. 1. What is stress?
Ans. Stress refers to adverse conditions for crop growth and production imposed by either biotic or abiotic factors.
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Q. 2. What are biotic factors?
Ans. Living organisms such as diseases, insects and parasitic weeds which cause stress conditions for crop growth and production are called biotic factors.
Q. 3. What is biotic stress?
Ans. Biotic stress refers to adverse conditions for crop growth and production imposed by biotic factors such as diseases, insects and parasitic weeds.
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Q. 4. What are abiotic factors?
Ans. Non-living factors such as drought, salinity, alkalinity, acidity, cold, frost, heat etc. which adversely affect crop growth and production are called abiotic factors.
Q. 5. What is abiotic stress?
Ans. Abiotic stress refers to adverse conditions for crop growth and production caused by abiotic factors. It is also known as environmental stress.
Q. 6. What is drought?
Ans. Condition of soil moisture deficiency or water scarcity is known as drought.
Q. 7. What are mechanisms of drought resistance?
Ans. There are four mechanisms of drought resistance as follows:
(i) Drought escape
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(ii) Drought tolerance
(iii) Drought avoidance
(iv) Drought resistance
Q. 8. What is drought escape?
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Ans. Ability of crop plants to complete their life cycle before the start of moisture stress in the field is known as drought escape. Early maturing varieties generally escape from late season drought.
Q. 9. What is drought avoidance?
Ans. Ability of plants to maintain a favourable internal water balance under moisture stress is referred to as drought avoidance.
Q. 10. What is drought tolerance?
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Ans. Ability of crop plants to grow, develop and reproduce normally under moisture deficit conditions is called drought tolerance. In other words, it refers to survival of crop plants under water deficit conditions without injury.
Q. 11. What is drought resistance?
Ans. Ability of crop plants to give higher yield under moisture stress conditions is known as drought resistance. It refers to good yielding ability under moisture deficit conditions.
Q. 12. What is moisture stress?
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Ans. In the soil, moisture deficit conditions which make survival of the plants difficult or have adverse effects on the plant growth and reproduction is referred to as moisture stress.
Q. 13. What is drought hardening?
Ans. Improvement in drought tolerance ability of a genotype through various seed and seedling treatments is called drought hardening.
Q. 14. What is salt tolerance?
Ans. Ability of crop plants to prevent, reduce or overcome the injurious effects of soluble salts present in the root zone is called salt tolerance.
Q. 15. What is hydroponics?
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Ans. Hydroponics refers to growing of plants in the nutrient solution.
Q. 16. What is lysimeter?
Ans. Cemented micro plots of various sizes which are used to undertake study on roots and salt tolerance are called lysimeters.
Q. 17. What is porometer?
Ans. An instrument which is used for measuring stomatal aperture is called porometer.
Q. 18. What is psychrometer?
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Ans. An instrument which is used to measure tissue water potential in plants is known as psychrometer,
Q. 19. What is tensiometer?
Ans. An instrument which is used for measuring soil moisture is known as tensiometer.
Q. 20. What are xerophytic plants?
Ans. Plant species showing normal growth and development under moisture stress conditions are called xerophytic plants.
Q. 21. What are mesophytic plants?
Ans. Those plant species which grow well under average or normal moisture conditions are known as mesophytes.
Q. 22. What are hydrophytic plants?
Ans. Those plant species which exhibit normal growth and development under excessive moisture conditions are called hydrophytes. Such plants can withstand water stagnation in the field.
Q. 23. What are oxylophytes?
Ans. Plant species which exhibit normal growth and development under acidic soil (soil acidity) are called oxylophytes.
Q. 24. What are halophytes?
Ans. Plant species which exhibit normal growth and development under salinity conditions are termed halophytes.
Q. 25. What are glycophytes?
Ans. Plant species which are sensitive to high salt concentrations (cannot tolerate high salt concentrations) are called glycophytes.
Q. 26. What are lithophytes?
Ans. Plants which can grow on hills are called lithophytes.
Q. 27. What are sociophytes?
Ans. Plants which exhibit normal growth and development under shade conditions are called sociophytes.
Q. 28. Which areas are more prone to drought?
Ans. Arid and semi-arid areas are more prone to drought conditions. About 36% of the land area constitutes arid and semi-arid zones.
Q. 29. What are effects of drought?
Ans. In crop plants, drought leads to reduction in both quality and yield. It has adverse effects a plant growth and development. Drought damages chloroplasts and lowers output of the photosynthetic apparatus. Drought leads to increase in proline, abscisic acid and ethylene in the leaves.
Q. 30. What are morphological traits associated with drought?
Ans. Following morphological characters of crop plants are associated with drought resistance:
(i) Earliness.
(ii) Lesser number of stomata per unit area on leaves.
(iii) Thick and small leaves.
(iv) Leaf and stem waxiness.
(v) Deep root system.
(vi) Determinate growth habit.
Q. 31. What are physiological characters associated with drought?
Ans. Following physiological characters are associated with drought resistance:
(i) High photosynthetic rate.
(ii) Low transpiration rate.
(iii) High osmotic concentration.
Q. 32. What are sources of drought resistance?
Ans. In crop plants, following are main sources of drought resistance:
(i) Cultivated varieties.
(ii) Germplasm collections.
(iii) Wild relatives and wild species.
(iv) Induced mutations.
Q. 33. What are measurements of drought resistance?
Ans. Main ways of measuring drought tolerance/resistance are given below:
(i) Higher leaf water retention under drought conditions,
(ii) High rate of photosynthesis under drought conditions.
(iii) Superior yield performance under drought conditions.
(iv) Deep root system.
Q. 34. What are indicators of drought?
Ans. Indications of drought are given below:
(i) Rolling of leaves.
(ii) Increase in proline level in leaves.
(iii) Soil moisture deficit.
Q. 35. How drought tolerance is measured in rice?
Ans. In rice, the force required to pull out the seedlings from paddy soil is used as a measure of drought tolerance.
Q. 36. What are drought tolerant varieties of sugarcane?
Ans. Drought tolerant varieties of sugarcane are COS 510, BO 1, CO 1148, CO 449, CO 997, CO 1158, CO 62175 and CO 6907.
Q. 37. What are drought tolerant varieties of wheat?
Ans. In bread wheat, drought tolerant varieties include NP 4, NP 720, PB 9-D, C 217, C 281, K 46, RS 31-1, AO 88, AO 113 and AO 115.
Q. 38. What are drought tolerant varieties of durum wheat?
Ans. In durum wheat, varieties Motia, Gulab, Jay and Arnej are resistant to drought.
Q. 39. What are drought tolerant varieties of Cowpea?
Ans. In Cowpea, varieties IGFRI 437 and IGFRI 450 are resistant to drought.
Q. 40. Which is drought tolerant variety of rice?
Ans. In rice, variety Akashi is drought tolerant.
Q. 41. What is drought tolerant variety of barley?
Ans. In barley, variety Karan-280 is tolerant to drought.
Q. 42. What are drought tolerant varieties of groundnut?
Ans. In groundnut, varieties Jyoti and HD 3-30 are drought tolerant.
Q. 43. What are drought tolerant varieties of sunflower?
Ans. In sunflower, varieties EC 68414 and EC 68415 are tolerant to drought.
Q. 44. What is drought tolerant variety of pearl-millet?
Ans. In pearl-millet, variety BJ 104 is tolerant to drought.
Q. 45. What are salinity tolerant varieties of sugarcane?
Ans. In sugarcane, varieties CO 453, CO 997, CO 62399, CO 7717, CO 1148, COS 767 and BO 91 are tolerant to soil salinity.
Q. 46. What is salinity tolerant variety of okra?
Ans. In okra, variety Pusa Sawani is salinity tolerant,
Q. 47. What are salinity tolerant varieties of barley?
Ans. In barley, varieties Ratana, RS 6, Karan 18, Karan 19 and Karan 92 are tolerant to salinity,
Q. 48. Give name of one salinity tolerant variety of rice.
Ans. Variety Mohan of rice is tolerant to salinity.
Q. 49. What are drought tolerant varieties of cotton?
Ans. In cotton, varieties MA 9 and MCU 10 are tolerant to drought.
Q. 50. What are drought tolerant varieties of onion?
Ans. In onion, varieties Hisar 2 and Punjab Selection are tolerant to salinity.
Q. 51. What is full name of Soil Salinity Institute of India?
Ans. In India, research work on soil salinity is carried out at the Central Soil Salinity Research Institute, Karnal and State Agricultural Universities.
Q. 52. What are differences between drought avoidance and drought tolerance?
Ans.
Main differences between drought avoidance and drought tolerance are presented below in Table 28.1:
