Biotech and novel crops

Give some examples of how technology has changed our food.

How does traditional plant breeding methods work?

A desirable trait is identified in a wild species, this wild species is crossed with the domestic variety. This might produce offspring with both the desirable trait and the undesirable ones. The ones with the desired traits are crossed with members of the domesticated species again. This continues until desired outcome. 

How and why are transgenic plants made? Give some examples.

A transgene is a gene that has been transferred from on organism into another,this can occur both in nature as well as in a genetic engineering lab. Transgenic plants are usually made to increase yield, nutrition or more resistant to diseases.

How can we use plant breedng or biotechnology to improve crops? 

Chemicals, radiation, natural variation, CRISPR or transgenes – what
are the pros and cons to use these to get new traits?

Can we create ”natural” Bt or Herbicide tolerant (Ht) GMOs using
CRISPR/Cas?

Should we allow CRISPR modified crops in organic agriculture? Should
they be labelled?

Bt and herbicide resistant GMOs are the most popular. What is the
next big GMO to create? How can we do it?

Name two mechanisms of asexual reproduction.

Fragmentation: detached roots and stems of some plants can develop into offsprings, occurs from budding in potatoes.

Apomixis: The production of seeds without pollination or fertilization, occurs in dandelions. A diploid cell gives rise to the embryo, the ovules mature into seeds which are then dispersed by the wind. This process is of interest to plant breeders to introduce in hybrid crops since it would allow hybrid plants to pass desirable genomes intact to offspring.

What are the advantages and disadvantages of asexual reproduction? 

Advantages:
No need for pollination, beneficial where plants of the same species are sparsly distributed. 
Passes on all the genetic material to it’s progeny, if the plant is well suited to an environment, this is very beneficial. 
Vegetative reproduction (growth from stems, leaves or roots) produces stronger seedlings than those from sexual reproduction. 

Disadvantages:
The genetic uniformity might expose the plants to local extinction if the conditions of the environment changes.

What are the advantages and disadvantages of sexual reproduction? 

Advantages:
Generates variation in offspring and therefore might be more adaptable to new or unstable environments.
Greater distribution due to seed dispersal. 
Seed germination can be delayed until environmental conditions are favorable, ensuring and maximizing growth. 

Disadvantages: 
Seeds are tougher than the seedlings, seedlings are exposed to predators etc. 

What mechanisms exists to prevent self-fertilization?

Self-incompability: The rejection of a plants own pollen and the pollen of closely related individuals. The recognition of “Self” pollen is based on genes called S-genes. There are two types of self-incompability, gametophytic and sporophytic.

Gametophytic: S-allele in the pollen genome governs the blocking of fertilization.
Sporophytic: fertilization is blocked by incompabilities between S-allele gene products present in the sporophytic parental tissue adhering to the pollen wall and S-allele products secreted by the stigma of the receptive flower.

How do plant-breeders prevent self-fertilization?

By removing the anthers (ståndare) from the parent plants or use male-sterile strains of the crop plants.

What does totipotent mean? 

Any cell in a multicellular organism that can divide and asexually generate a clone of the original organisms is said to be totipotent. This is found in many plants, particularly in their meristematic tissues. This is the underlier to most techniques used by humans to clone plants. 

Explain vegetative propagation.

When vegetative reproduction is used by humans. Cuttings are plant fragments that has usually been taken from shoots of plants.
The wounded end of the shoot starts developing totipotent cells called callus. Roots develop from the callus.

What is grafting? What is stock and scion?

Grafting is when a severed shoot from one plant is permanently joined to tre stem of another plant. This is usually done to closely related individuals and can combine the best qualities of different species or variations into one plant. The plant that provides the roots is called the stock and the twig grafted onto the stock is known as the scion.

How can plant breeders hasten mutations?

By treating large batches of seeds or seedlings with radiation or chemicals.