Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Plant Genetics and Crop Improvement > Test Bank > Flashcards

Test Bank Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Inbreeding (self-pollination; sib-mating) results in…

A

Increased frequency of homozygotes; decreased heterozygosity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Random mating results in…

A

Genotypic and phenotypic frequencies that are a function of gene frequency.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

If the broad sense heritability for a trait is 56%, it is known that the contribution of the environment to the total phenotypic variance is…

A

44%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Genetic uniformity among cultivated species (a narrow genetic base) can have a consequence known as…

A

genetic vulnerability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Heritability in the narrow sense is best defined as the…

A

ratio of additive genetic variance to phenotypic variance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

If mass selection for a trait is not effective, that would generally mean that…

A

the trait has a low heritability.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

A major advantage of the bulk method of inbreeding a population is that…

A

natural selection can work to increase the proportion of desirable types.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Selection against a recessive allele that is low in frequency in a population in Hardy-Weinberg equilibrium…

A

is inefficient because most of the alleles are “hiding” in heterozygotes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

One of the assumptions underlying the Hardy-Weinberg principle is…

A

mating is at random.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The basic goal of recurrent selection is to…

A

change the mean in a desirable way while maintaining the degree of genetic variation in population.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

A type of recurrent selection that would be best suited for traits with low heritability would be…

A

full-sib recurrent selection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

“Gridding” as a concept of recurrent selection as proposed by Burton and others was done primarily to…

A

reduce environmental variability and bias.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The final phase in the development of inbred lines for use in commercial F1 hybrids is…

A

individual line testing for specific combining ability.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Among the following which is the preferred genotype to use as a source of a particular gene, assuming all genotypes are of equal value?

A

an obsolete cultivar well-adapted to the area, in the same genus and species as the cultivated type.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

In a population with two alleles, B and b, the frequency of B is 0.43. The frequency of heterozygotes, assuming Hardy-Weinberg equilibrium, would be…

A

0.49

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Variance can best be described as…

A

A measure of the spread of the distribution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

A recessive lethal gene can persist for many generations in a population when…

A

The recessive allele is rare.

18
Q

Mass selection works best with…

A

traits of high heritability.

19
Q

The phenotypic variance among the F1 generation plants of a cross between two homozygous or inbred lines is assumed to be equal to…

A

the environmental variance.

20
Q

The ratio of the total genotypic variance to total phenotypic variance is called…

A

Broad-sense heritability.

21
Q

A heritability estimate of 0.50 means…

A

50% of the variation in a population is due to environmental factors.

22
Q

A modification of the Bulk Method that overcomes the disadvantage of unintended selection for certain yield components (such as seed size and number) in the Bulk Method is…

A

Single-seed descent.

23
Q

One advantage of the Pedigree Method of selection is…

A

it is possible to determine the inheritance or heritability of specific traits.

24
Q

Recurrent selection can be envisioned as a circular process, with an event sequence…

A

Create population -> evaluate individuals -> intermate the population -> create a population

25
Q

As opposed to other Breeding Methods, Early Generation Testing is primarily concerned with…

A

Evaluation of Populations rather that individuals within populations.

26
Q

Single-seed descent has one particular advantage over other methods of inbreeding, which is…

A

It is possible to move through generations rapidly, as many as 3 per year.

27
Q

One reason it is difficult to use recurrent selection in self-pollinated crops is…

A

It is difficult to achieve the necessary generations of intermating in self-pollinated crops.

28
Q

The overall goal of recurrent selection is to…

A

Improve the mean performance of a population without a reduction in genetic variance.

29
Q

Phenotypic recurrent selection is best suited for…

A

Traits with high heritability.

30
Q

A major disadvantage of the backcross method of crop improvement is…

A

It does not work well with quantitative traits.

31
Q

The two major types of evaluation in recurrent selection are…

A

Phenotypic and genotypic.

32
Q

The method of generation advance and selection that relies most heavily on natural selection to increase the frequency of desired genotypes is the…

A

Bulk Method

33
Q

The amount of genetic gain (gain from selection) is dependent upon the genetic variance, the phenotypic variance and the…

A

Selection intensity.

34
Q

Maximum genetic diversity for a species is usually found in…

A

Areas of long-time cultivation or species origin.

35
Q

The major difference between Early Generation Testing (EGT) and other selection methods for self-pollinated crops is…

A

EGT is primarily to identify superior populations from which to select, rather than individuals within populations.

36
Q

The method of generation advance and selection that relies most heavily on natural selection to increase the frequency of desired genotypes is the…

A

Bulk Method.

37
Q

The method of selection of selection that can work well in combination with either the Bulk Method or Mass Selection is…

A

Single-seed descent.

38
Q

A major advantage of the pedigree method over other selection and generation advance methods is…

A

It allows determination of the mode of inheritance of traits of interest.

39
Q

Which cross is likely to generate the most genetic variance in the succeeding generations following the cross?

A

Cultivar x wild accession

40
Q

In analyzing the broad sense heritability for a trait, an h^2 value of 0.9 indicates that…

A

phenotypic and genetic variance are about equal.

41
Q

Parents differing in qualitative genes at 4 loci (AABBccdd and aabbCCDD) are crossed. Progeny are advanced by self-pollination to the F8 generation. With regard to the 4 loci, approximately how many different genotypes are recovered in the F8?

A

2^4

42
Q

One of the assumptions underlying the Hardy-Weinberg principle is…

A

mating at random.

Plant Genetics and Crop Improvement (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions