Unit 4: Haploid Production, Somaclonal Variations and Plant Microbe Interactions - Practice Quiz

1 Anther culture is a technique used to produce plants that are:

2 In anther culture, the haploid plants develop from which cells?

3 The production of haploid plants from the male gametophyte (pollen/microspore) is called:

4 The production of haploid plants from the female gametophyte is known as:

5 Ovule culture is mainly used to obtain haploids through:

6 The phenomenon of pollen grains switching from the normal gametophytic pathway to the sporophytic pathway in anther culture results in:

7 Doubling the chromosome number of a haploid plant produces a:

8 Which chemical is most commonly used to double the chromosome number in haploid plants?

9 A major advantage of using haploids in plant breeding is the rapid production of:

10 Somaclonal variation refers to the genetic variation observed in plants regenerated through:

11 The term 'somaclone' was coined to describe plants derived from:

12 Variation arising specifically from cultured gametic (germ) cells is often referred to as:

13 In vitro selection of somaclonal variants often uses a selective agent added to the medium such as:

14 Somaclonal variation is useful in crop improvement mainly because it can generate plants with:

15 A limitation of somaclonal variation in crop improvement is that some variations are:

16 Which factor increases the frequency of somaclonal variation during tissue culture?

17 In vitro plant-microbe interaction assays are performed under conditions that are:

18 A common purpose of in vitro plant-microbe assays is to study:

19 A key limitation of in vitro plant-microbe interaction studies is that they may not fully reflect:

20 In vitro plant-microbe interaction techniques are widely applied to study beneficial associations such as:

21 In anther culture, the developmental stage of pollen most favorable for inducing androgenesis is usually the:

22 A researcher recovers many diploid and mixoploid plants from an anther culture instead of pure haploids. The most likely source of these diploids is:

23 The essential difference between androgenesis and gynogenesis in haploid production is that:

24 Gynogenesis is often chosen over androgenesis for a particular crop when:

25 Unpollinated ovary or ovule culture for haploid production must typically be initiated:

26 The main advantage of using doubled haploids (DH) over conventional inbreeding in plant breeding is that DH lines:

27 Haploids are especially valuable for detecting recessive mutations because in a haploid:

28 To convert a haploid plant into a fertile doubled haploid, the agent most commonly applied is:

29 Somaclonal variation is best defined as the genetic and epigenetic variation observed among plants that are:

30 A prolonged callus phase and higher levels of hormones such as 2,4-D during culture tend to:

31 To isolate cell lines resistant to a fungal toxin, the most direct in vitro strategy is:

32 A variant recovered in vitro that loses its altered trait after being transferred to selection-free medium is best described as showing:

33 Which technique is most appropriate for confirming that a selected somaclone carries a true chromosomal number change?

34 The disease-resistant sugarcane and potato somaclones developed commercially illustrate that somaclonal variation can be used to:

35 For a micropropagation industry aiming to produce genetically uniform planting material, somaclonal variation is regarded as:

36 Compared with conventional mutation breeding using chemical mutagens, an advantage of exploiting somaclonal variation is that it:

37 A key requirement when developing an in vitro dual-culture assay for a plant–pathogen interaction is:

38 In an in vitro assay to screen for a beneficial plant growth-promoting rhizobacterium, the most relevant positive readout would be:

39 A major limitation of studying plant–microbe interactions purely in vitro is that:

40 In vitro establishment of mycorrhizal or Rhizobium associations with plantlets is primarily applied to:

41 In anther culture, the developmental stage of the microspore at the time of inoculation is critical for successful androgenesis. If anthers are cultured too late (after the first pollen mitosis with a well-developed generative cell), which outcome is most likely?

42 A researcher obtains a high frequency of regenerated plants from anther culture but finds many are diploid and heterozygous rather than haploid. What is the most probable origin of these plants?

43 Ovule culture is often preferred over embryo culture in certain wide crosses. What is the primary rationale for culturing the intact ovule rather than excising the embryo directly?

44 Gynogenesis is used instead of androgenesis in species such as onion and sugar beet primarily because:

45 The 'bulbosum method' in barley produces haploids through a mechanism distinct from anther culture. Which best describes this mechanism?

46 Doubled haploid (DH) technology dramatically shortens breeding programs. Compared to conventional selfing to reach near-homozygosity, the key genetic advantage of DH lines is:

47 Why are haploids and doubled haploids especially powerful for mapping and selecting recessive mutations?

48 Cold pretreatment (e.g., 4°C) of anthers before culture improves androgenesis. The most widely accepted explanation for this stress effect is:

49 A somaclonal variant selected in vitro for herbicide tolerance loses the trait after a few generations in the field. This 'epigenetic' variation is best distinguished from a true genetic mutation because it:

50 To isolate salt-tolerant somaclones, cells are cultured on medium with gradually increasing NaCl. A limitation of this positive in vitro selection strategy is that:

51 Somaclonal variation frequency generally increases with which culture condition, making it a double-edged sword in micropropagation?

52 The disease-resistant sugarcane and the tomato variety 'DNAP-17' are cited examples of somaclonal variation. The chief advantage of using somaclonal variation over conventional mutation breeding here is that it:

53 A key criticism limiting the practical exploitation of somaclonal variation for crop improvement is that:

54 When developing an in vitro dual-culture assay to study a mycorrhizal symbiosis, a major methodological challenge with arbuscular mycorrhizal (AM) fungi specifically is that:

55 In designing an in vitro assay to screen for biocontrol activity of a rhizobacterium against a fungal pathogen, the most rigorous positive readout that distinguishes true antagonism from mere nutrient competition is:

56 A recognized limitation of studying plant–microbe interactions in vitro (axenic culture) rather than in soil is that:

57 Ri T-DNA transformed 'hairy root' cultures are extensively used in in vitro plant–microbe studies. Their principal advantage for such research is that they:

58 In doubled haploid production, colchicine is applied to double the chromosome number. If colchicine treatment is applied after several cell divisions of the haploid have already occurred, the likely consequence is:

59 Albinism is a frequent problem in cereal anther/microspore culture. The underlying cause of these albino regenerants is most often:

60 Consider a scenario where a somaclone shows an improved trait, but you must confirm it is a genuine, exploitable somaclonal variant. The most decisive evidence is that the trait: