Plant Breeding

Question 1

Sexual reproduction

Answer 1

The production of new living organisms by combining genetic information from two individuals of different types (sexes).
Benefits – variation in offspring,
Disadvantages – requires 2 parents

Question 2

Asexual reproduction

Answer 2

Is a type of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only
Benefits – same genetic information, reproduce quickly
Disadvantages – can pass on damaged genes, prone to extinction, can’t adopt to changing environments

Question 3

Self pollination

Answer 3

naturally pollinate their own flowers

Why – exactly the same

Question 4

Cross pollination

Answer 4

naturally pollinate other plants of the same species and frequently have mechanisms to prevent self-pollination
Why – Breed different characteristics Eg) higher yields, greater genetic variation

Question 5

Breeding systems

Answer 5

1. Collecting and selecting varieties that between them have the characterises required in the final crop or pasture
2. Crossbreeding the collected varieties to combine the desired characterises
3. Selecting among the offspring of the crosses those individuals that do have desired characterises
4. Evaluating the selected offspring for presence of the desired characterises under field conditions.

Question 6

Cross breeding

Answer 6

The collected varieties to combine the desired characteristics

Question 7

In breeding

Answer 7

Mating closely related relatives

Question 8

Gene

Answer 8

a unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring.

Question 9

Chromosome

Answer 9

a thread-like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes

Question 10

Genotype

Answer 10

Combination of alleles giving that appearance

Question 11

Phenotype

Answer 11

The appearance the organism has

Question 12

Impacts of environments on phenotype of a plant

Answer 12

P = G + E (Phenotype = Genotype + Environment)
The Environment includes all the factors that affect the yield of a species but are not genetic.
Eg) waterlogging, grazing, disease, late break of season, lack of nutrients, competition

Question 13

Aims of plant breeding

Answer 13

1. Grain - short variety, Hay - taller variety
2. Higher yield
3. Disease resistance
4. Increase in quality
5. Larger leaf to stem ratio
6. Maturing variety