Genetics and Plant breeding pointers 46

1. 2,4-D is the most frequently used auxin in tissue culture.

2. A cell without a nucleus is known as a eunucleate cell.

3. A chromosome with four chromatids produced by endoreduplication is called a diplochromosome.

4. A culture medium having no growth regulator is called basal medium.

5. A fusogen is a chemical that promotes fusion of protoplasts.

6. An inherent capacity of the host to resist pathogen-caused disease symptoms is called host resistance.

7. The number of copies of a gene in a particular genome is called amplification.

8. A pathogen that does not cause disease because the plant carries a specific resistant gene is said to be avirulent.

9. A reporter gene is also known as a scorable marker.

10. A shuttle vector propagates into cells of two different organisms without modification.

11. A single variety having resistant genes for different races of a pathotype is called gene pyramiding.

12. A suicide vector is a viral vector unable to replicate after gene delivery.

13. A terminal portion of the shoot (0.1-0.5 mm) containing the apical meristem and two or three youngest leaf primordia is called a shoot tip.

14. Tolerant varieties show lower reduction in yield despite disease symptoms.

15. A transfer gene is isolated from one organism and transferred to another, producing a transgenic plant.

16. Alfa-alfa variety Sigma is a polycross among selected somaclones.

17. Insects and diseases feeding on crop plants develop adverse effects.

18. An organism producing disease is called a pathogen.

19. Andro is a somaclone of flax.

20. Anther culture is generally used for the production of haploid plants.

21. A sporophyte with gametic chromosome number is known as haploid.

22. Barley variety Mingo Gwyian was developed as a homozygous diploid from a cross between H. vulgare and H. bulbosum.

23. Biffen (1905) proposed the concept of genetics of disease resistance.

24. Bio-13 is a variety developed from Citronella java.

25. Bollard is a cotton variety resistant to bollworm and budworm insects.

26. BXN is a cotton variety resistant to bromoxynil herbicide.

27. Calcium hypochlorite, sodium hypochlorite, and mercuric chloride are surface sterilants.

28. Calcium or sodium hypochlorite are surface sterilizing agents.

29. Caulimovirus and Geminivirus can be used in gene transfer but their use is limited.

30. A cell without cell wall and nucleus is known as a cytoplast.

31. Cellulase, pectinase, and macrozyme are cell wall degrading enzymes.

32. Chemically defined media containing inorganic salts, vitamins, sucrose, agar, etc. are called synthetic media.

33. Colchicine-treated haploid plants develop into homozygous diploid plants.

34. Cross protection occurs when a mild strain of virus infects a plant and makes it resistant to severe infection by the same or related virus.

35. Cry gene is isolated from Bacillus thuringiensis.

36. CryII protein is active against both Diptera and Coleoptera.

37. CryI protein is insecticidal to Coleoptera, and CryIII protein is specific to Diptera.

38. Cytokinin promotes cell division and shoot regeneration.

39. Deletion of oncogenes (cancer-producing genes) from T-DNA to make it suitable for gene transfer is called gene disarming.

40. A dikaryon cell contains two nuclei.

41. Disease is an abnormal condition in plants produced by pathogens.

42. Disease resistance depends on both host and pathogen genotypes.

43. Disease score of 0 means absence of disease symptoms.

44. DMSO, glycerol, and proteins are used as cryoprotectants during cryopreservation; DMSO is the most common.

45. DMSO, glycerol, or proline are cryoprotectants added to media to prevent cryoinjury.

46. DNA fragments are inserted into vectors and sealed by DNA ligase.

47. DNA that suppresses and expresses another gene is called a silencer.

48. DMSO stands for Dimethyl sulphoxide.

49. Early or mid-uninucleate stages in cereals are used for pollen culture.

50. Epidemics are common in airborne fungi.

51. Eradication of pathogens through chemicals is called chemotherapy.

52. Escaping damage due to disease or insects by susceptible host varieties is known as avoidance.

53. Evergreen is a somaclone of blackberry.

54. Every resistance gene in host and pathogen has a corresponding gene-for-gene relationship.

55. Flavr and Sqvr are transgenic tomato varieties developed using antisense RNA technology.

56. Flor proposed the gene-for-gene hypothesis.

57. Florin is the first haploid wheat variety developed in France.

58. Freedom II is a variety of squash.

59. G. Haberlandt is known as the father of plant tissue culture.

60. Gene-for-gene relation between host and pathogen was first proposed based on linseed rust.

61. Generally, 5 to 10 shoot pieces with some leaf primordia are used for meristem culture.

62. Generally, 2,4-D auxin is used in tissue culture at 0.5–2.0 mg/liter.

63. Aggressiveness of a pathogen refers to the severity of insect/disease damage caused to crops.

64. Interspecific or distant hybridization often requires embryo culture techniques.

65. During the pathogenic phase, pathogens are generally diploid.

66. Genetically identical varieties that differ only in resistance genes are called multiline varieties.

67. Genetics of disease resistance is due to resistance and virulence genes.

68. H.G. Khorana (1970) and coworkers synthesized analyI-tRNA for yeast genes.

69. Haploid has a gametic chromosome complement; monoploid has one copy of a single genome.

70. Heritable variation present in tissue culture is called somaclonal variation.

71. High concentrations of auxin are used for induction of somatic embryos in tissue culture.

72. HindII was the first restriction endonuclease discovered.

73. Horizontal resistance shows resistance to all races of a pathogen.

74. A hormone is a substance synthesized in one part of a multicellular organism that acts in another part.

75. A host that does not show symptoms despite pathogen inoculation is called immune.

76. Iaam and Iaah genes present in T-DNA govern tumor formation; bGV3850 and pMON 505 are examples of binary vectors.

77. Iaam, iaah, and ipt genes are involved in tumor formation.

78. If there are n differential hosts and r disease reactions, the number of physiologic races is (r^n).

79. In alloplasmic lines, the nucleus is from one species, and the cytoplasm is from another.

80. In auxotrophic mutants, a negative selection approach is required.

81. In biotic stresses, one organism adversely affects the performance of another.

82. DNA sequencing is the determination of the base sequence of a DNA molecule.

83. In the hypersensitive response, the plant shows cell death around the site of pathogen invasion.

84. In an immune reaction, the reproduction rate of the pathogen is zero.

85. Epigenetic variation is not transmitted during meiotic division.

86. Parasexual hybridization produces hybrids without gamete fusion.

87. Pathogen inoculum landing on the host is called contact.

88. Insertion of viral genome or vector into plant cells within T-DNA of Ti plasmid is called agroinfection.

89. Interaction between host and pathogen is called infection.

90. Jenson proposed the concept of multiline varieties of oats.

91. Jinghua 1 and Shinshu are haploid-derived varieties of wheat and rice, respectively.

92. Joining two DNA segments by a phosphodiester bond is known as DNA ligation.

93. K.C. Mehata discovered the life cycle of rust in India.

94. Kary Mullis (1985) discovered the polymerase chain reaction (PCR).

95. Kbp stands for kilobase pair.

96. Kinetin and benzylaminopurine (BAP) are commonly used cytokinins in tissue culture.

97. Larkin and Scowcroft (1981) coined the terms somaclonal variation and somaclone.

98. Leaf mesophyll cells produce the best protoplasts in dicot plants.

99. Mango is the first haploid variety of barley developed in Canada.