Lecture 17 - Selecting

Question 1

what is the difference between bulk and pedigree breeding methods

Answer 1

• bulk: bulk for many generations and then start selection
  -pedigree: start selecting from beginning and take individuals each generation

Question 2

2 common variants of bulk method

Answer 2

modified bulk
F2-derived family method

Question 3

modified bulk method

Answer 3

bulk population is planted and best plants are selected. They are then bulked and planted to produce plants for next gen until satisfied (typically F5). progeny rows are then grown from selected plants and performance test trials are performed via pedigree method

Question 4

t/f: modified bulk method is a compromise between the bulk and pedigree methods (more resources then bulk, less than pedigree)

Answer 4

t

Question 5

what do you lose when you use modified bulk method

Answer 5

lose the familial relationships/ the fake replication

Question 6

F2-derived family method

Answer 6

individual plant selections are made in F2 and then subsequent generations are bulked and grown in rows or microplots until homozygosity is reached. culling occurs at each gen and can trace back to 1 F2 plant

Question 7

objective of doubled haploids

Answer 7

to produce a population of completely homozygous lines in a short time by using tissue culture procedures

Question 8

basic procedures of doubled haploids

Answer 8

-produce haploid plant from population which have heterozygous loci (typically F1)
-homozygous lines produced by doubling the chromosomes of the haploid plants
-evaluate lines using pure-line selection

Question 9

Wide hybridization

Answer 9

using a wild relative to fool the ovule into thinking it has been fertilized, generating haploid embryos that must be rescued

Question 10

type of doubled haploid method

Answer 10

microspore culture

Question 11

microspore culture

Answer 11

immature pollen is isolated and cultured so they germinate as haploid plants. The chromosomes are then artificially doubled using mitotic inhibitors

Question 12

the success rate of microspore culture is ________ dependent

Answer 12

genotype

Question 13

what do you need to watch out for in microspore culture

Answer 13

segregation distortion
meiotic instabilities
chromosomal abnormalities
somaclonal variation

Question 14

what a major concern of using double haploidy

Answer 14

only has 1 meiotic event/less recombination so it will be harder to break up negative linkage