Test 1-1996

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Plant Science 446/546

Class Test February 22, 1996

12:15 to 1:15

Ag.Sci Room 339

Name :

Answer all

8

questions

A total of 100 points are available

Points available from each part of each question are shown in bold square parenthesis

Try to be as brief and concise as possible

Please write in a legible form

Show any working/calculations

Make sure that any additional paper used is attached to the questionnaire

1

1.

2a.

Briefly, describe one major problem that can be encountered,

or

one attribute of the crop type that can be utilized, when breeding:

[4 points]

1.

2.

3.

4. a pure-line cultivar; a out-pollinated cultivar; a hybrid cultivar; a clonal cultivar.

2b.

3a.

3b.

In order to justify development of hybrid cultivars it is necessary to have some method of producing inexpensive hybrid seed. Outline three systems that have been used to produce hybrid seed and indicate any advantages or disadvantages of each system.

[6 points]

.

1.

2.

3.

Design a breeding scheme (using diagrams as necessary) to develop a new hybrid corn cultivar that will use a

cytoplasmic male sterile system

for seed production

[10 points]

.

Discuss the advantages and disadvantages of a bulk and a pedigree breeding scheme when developing new cultivars of an inbreeding crop

[6 points]

.

(a) Bulk breeding scheme

(b) Pedigree breeding scheme

You have been asked to design a breeding scheme to develop a replacement for

`Steptoe' (the leading spring malting barley in North Idaho). Outline the scheme you would chose (use diagrams as necessary) and explain why you chose this breeding scheme.

[10 points]

4. `Russet Burbank' has been the predominant potato cultivar in the Pacific Northwest for many years. You have been asked to design a breeding program that will produce cultivars that can replace some of the Russet Burbank acreage. Outline the

2

5a. breeding design you would use indicating:

(a)

(b) five breeding objectives

1.

2.

3.

4.

5.

[5 points]

; the breeding scheme (use diagrams if necessary), indicating number of clones evaluated and selected at each stage

[10 points].

5b.

5c.

6.

In plant breeding, two main disease resistance mechanisms exist,

inhibition of infection

and

inhibition of growth after infection

. Explain (with examples if necessary) each of the mechanisms

[5 points]

.

Explain the terms

tolerance

and

escape

in relation to breeding for insect resistance.

How do tolerance and escape differ from plant resistance mechanisms

[5 points]

.

Discuss the difference between

durable

and

non-durable

insect resistance. Include any examples (using either disease or pest) in your answer.

[5 points]

.

Many believe that the beginning of man's civilization began with the beginnings of agriculture (although no one is alive from that time period to say for sure). Basically there are two forms of agriculture: (1) rearing animals for meal, milk etc. and (2) raising crops for human or animal feed. No one knows which form of agriculture came first (or maybe both types started together). Explain why (in your opinion) one form came before the other or both forms evolved at the same time.

[10 points]

.

7. You have been offered a job as Senior Plant Breeder with the "Dryeye Onion

Company" in Southern Idaho. Your first task in this new position is to set breeding objectives for onion cultivar development.

(a)

(b)

Outline the main points to be considered when setting your breeding objectives

[5 points]

; indicate what questions you would like answered to enhance the breeding objectives you will set.

[5 points]

.

3

8a.

8b.

You did so well in your last position as onion breeder that you have been asked to be

Vice-President of Research and Development (with a whopping big salary and many great benefits) at the "Grassland Gene-Tech Co.". One of the objectives of this

stock share funded

company is to develop new synthetic cultivars of rye grass.

You are to explain the breeding system used to develop these synthetic cultivars to a share holders meeting. Outline the main aspects of the breeding scheme and explain the advantages of synthetic lines over open pollinated cultivars to these share holders.

[8 points]

.

After several rounds of clonal selection breeders in you company have identified 4 potential high production rye grass parent lines for developing a new synthetic (lines are coded as

A, B, C,

and

D

). F

1

hybrid seed was produced from all parent cross combinations possible and these F

1

's were evaluated in yield trials along with the parent lines. From the yield (kg/ha) results (below) indicate the

three parent

synthetic most likely to be highest yielding

and

estimate its expected yield

[6 points]

.

Parent A = 118 Parent B = 122 Parent C = 121 Parent D = 125

A x B = 125

B x C = 130

A x C = 126

B x D = 121

A x D = 124

C x D = 124

4

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