Lecture 3 - Gathering Variability

Question 1

who was Seager Wheeler

Answer 1

made Marquis 10B wheat (most grown wheat variety for 30yrs) by identifying off-types and was crowned World Wheat King 5 times

Question 2

what is economic yield

Answer 2

portion of plant biological yield that humans use

Question 3

breeding

Answer 3

selecting plants with traits that are superior to those previously found in the population

Question 4

where do alleles arise from when crossing

Answer 4

-mutations
-local and genome duplications (autopolyploidy)
allopolyploidy

Question 5

when is there less genetic recombination

Answer 5

there is less recombination near centromeres/less distance because it causes blocks of alleles to be inherited together)

Question 6

linkage blocks

Answer 6

blocks of alleles inherited together

Question 7

what does genetic linkage cause

Answer 7

decreases ability to create variability

Question 8

how does temperature affect recombination

Answer 8

it has different impacts in males and females
can affect crossover events and break linkage

Question 9

what is required to get genetic recombination

Answer 9

mating systems (Sexual or asexual)

Question 10

what determines the genetic structure of a population

Answer 10

mating systems

Question 11

2 types of a population

Answer 11

natural and cultivated

Question 12

how can knowing the type of reproduction of your crop be important for breeding decisions

Answer 12

determines the form of the end product and the breeding methods to be used

Question 13

cultivar types (end products)

Answer 13

pure lines
multi-lines
hybrids
open pollinated (synthetics)
clonal
apomyctic

Question 14

genetic characteristics of inbreeders (self-pollinated plants)

Answer 14

low recombinant genotype frequency
high local fitness
uniform populations
deleterious recessives rare

Question 15

mating of outcrossing plants occurs between ______ individuals

Answer 15

unrelated

Question 16

what is outcrossing plants typically considered to be in

Answer 16

Hardy-Weinberg equilibrium (random mating)

Question 17

which parent do you know when you select

Answer 17

typically only known female. male is completely unknown due to pollen

Question 18

genetic characteristics of outcrossers (outcrossing plants)

Answer 18

-high recombinant genotype frequency
-variable fitness
-can more readily adapt to new environments
-carry and hide deleterious recessives
-susceptible to inbreeding depression

Question 19

2 types of asexual reproduction

Answer 19

vegetative propagation
apomixis

Question 20

vegetative propagation

Answer 20

plant tissue other than seed is used to produce a clone (ex: cuttings and tissue cultures)

Question 21

apomixis

Answer 21

plant embryos develop from megaspore mother cell without fertilization

Question 22

genetic characteristics of asexual reproduction

Answer 22

-all progeny are identical to the parent plant (no genetic variation)
-can maintain a superior genotype

Question 23

types of mutation effects on organisms

Answer 23

silent, missense, and non-sense

Question 24

silent mutation

Answer 24

same amino acid coded for so there is no change in phenotype

Question 25

missense mutation

Answer 25

change of amino acid produces a different protein which changes the phenotype

Question 26

non-sense mutation

Answer 26

codon is changed to stop codon which prematurely stops translation and produces a different or lethal phenotype

Question 27

what are the compounds in faba bean that cause favism (Acute Hemolytic Anemia)

Answer 27

Vicine and Convicine

Question 28

plant breeders are only interested in mutations if they …..

Answer 28

affect a plants ability to reproduce or affect plant’s end-use quality
and occurs in cells that produce gametes

Question 29

where do different alleles come from

Answer 29

-mutations
-variation in chromosome # (polyploidy)

Question 30

genome

Answer 30

each basic set of chromosomes characteristic of a species

Question 31

ploidy

Answer 31

the number of sets of these chromosomes

Question 32

diploid

Answer 32

2 sets of chromosomes

Question 33

haploid

Answer 33

1 set of chromosomes

Question 34

polyploid

Answer 34

more than 2 sets of chromosomes

Question 35

examples of a tetraploid (4x), hexaploid (6x), and octoploid (8x)

Answer 35

4x - durum wheat
6x - bread wheat
8x - strawberries

Question 36

autopolyploid

Answer 36

multiple copies of the same genome in an individual (ex: alfalfa AAAA)

Question 37

allopolyploid

Answer 37

several genomes within a single individual and acts like a diploid ex: bread wheat AABBDD

Question 38

advantages to polyploidy

Answer 38

-increased vegetative vigour
-facilitates new gene combinations that wouldn’t occur in a diploid
-possibility of recessive is much lower
-can combine genomes to create new species
-allows duplicate locus differentiation

Question 39

when can a triploid occur

Answer 39

when an accidental unreduced diploid gamete pairs with a normal haploid one or when you cross a diploid with a tetraploid

Question 40

what happens when a triploid attempts to pair during meiosis

Answer 40

generates massive genetic imbalances upon cell division and typically produces a sterile plant

Question 41

how are triploids maintained

Answer 41

seed propagation is only possible if it is a result of a diploid x tetraploid
otherwise vegetative propagation is necessary

Question 42

examples of useful triploids

Answer 42

banana
seedless watermelons
some flowering plants