Hybridization -

genetic modification & organic

Hybridization - Genetic modification & organic                          NZ Horticulture 2002

 

 

It is only right that we should be scared about any tampering that affects the make-up of the food we put on our tables and that we should be frightened by closet manipulation of any organism. That old deep fear of relinquishing control to unknown forces.

A number of words by association, tumble into focus when the questions arise.  Words covering choices of growing methods currently in favour include organics and  bio-dynamics and then the alarm triggers, like GE and GM hybridization?

In the GE & GM debate, where does hybridization fit in?  Is there a difference between GE & GM?

But general background information on hybridization, even a basic word description, is elusive.  A very limited amount of information seemed available in response to initial research feelers from my desk.

 

A hybrid is the offspring of 2 plants or animals of different species or varieties.

Is there a difference between GE & GM?  Do the 2 terms mean the genes have been manipulated but whereas GM means modified within a plant type, GE means the crossing of genes from one plant type or organism to another?

I understand hybridization to be a naturally occurring phenomena of genetic modification, which may be assisted by man to speed the process of evolving commercially desirable varieties.

 

Dr Pike, Director (retired) of The Vegetable & Fruit Improvement Centre at Texas A&M University, has some answers:-

"The question you ask is a good one. Traditional hybridization is crossing  plants with different characteristics to create seeds that segregate into many new different plants when grown. The new plants can have almost unlimited new traits depending on the diversity of the two parents. This hybridization can be between two commercial varieties or between a commercial variety and a wild weed type growing in the wild. Most new improved fruit, vegetable and agronomic varieties have been developed using this method. Corn, wheat fruits and vegetables were at one time all weed types.

The term biotechnology should be used for this type of breeding as well as for gene (trait) transformation. However, scientists doing trait transformation have "coined" this term to distinguish the creation of new plants through inserting a gene or a few genes from one plant or animal in some cases, into another plant. This has been done with a 'gene gun' where genetic material has been inserted into cells of a plant,  by small blast,  into another plant. Other methods include putting genetic material into a bacteria and then introducing that bacteria carrying the gene into another plant. This can be used to get foreign genes into plants that cannot be introduced by natural crossing.

I think the most resistance from consumers to the new way of introducing different genes is the fear that other genes not intended to be introduced into the new plant may occur. Also new inserted genes may not produce the intended results as sometimes two genes will work together to give very different results than either gene by itself.

I have heard from many people the complaint that they wanted to know which new varieties were so called GMO. There has been resistance by biotechnologists to want to disclose GMO's in new varieties and this worries a lot of people.

I think GMO's will be very valuable if used correctly and safely in the future. It is going to have to be done with a good understanding by scientists to be totally sure of what their goals are and to do a good job of letting consumers know and understand the process.

A second thing that has happened is that some companies have found that to sell their products as "Non GMO" is a good marketing tool. In some instances they are not selling more of their products but at a higher price."

 

GE, GM questions, proliferate and raise real concern, but unfortunately, because of their complexity and the loud voice of vested interest groups, are seldom answered clearly and satisfactorily.  A wave of uncertainty and suspicion in relation to short and long term health effects heavily hangs around the consumption of ‘tampered’ food items linked to genetic manipulation. The dictionary description describes – genetic engineering  as the deliberate modification of the characteristics of an organism by the manipulation of DNA and the transformation of certain genes. 

Anything including the word genetic starts to raise suspicion. It leads to recollection of TV series of the 70s about Andromeda – a then perceived to be far fetched story about a beautiful woman growing from a single cell as a result of scientific experiments. 

Where do scare-mongering and common sense meet?  My thoughts reach back to biology classes at school, and the talk of plant components. As a gardener, I think of the beautiful roses of David Austin and our own Sam McGready, as a result of plant breeding. What clearly comes to mind is remembering a life-time of talk referring to hybrids.  

Where do Bio-dynamics fit in?

What about pure organics – Where does the use of blood and bone as a natural fertilizer fit in? Blood and bone, is just that. When you think what this actually is, the thought is not a pleasant one.

‘The Creative Food and Lifestyle Magazine’, March-May 2001 ran an article ‘What is organic food?’  It says in the vegetable marketplace, there are organic and certified organic vegetables.  Vegetables from organic farms that have not been inspected by an accredited organic certifier carry an organic label. Whereas produce carrying the label ‘certified organic’ are certified and are inspected on a yearly basis by an organic certifier e.g. Bio-Gro (NZ).  ‘Vegetables grown in backyards cannot be termed organic, even if they are grown without pesticides or artificial fertilizers.  They are best referred to as natural foods.  To qualify to use the term organic, food must satisfy many conditions and  certified organic products must bear the certifier’s logo.

 

“Transgenic Onions are on the way’ Dr. Mike Havey in the September 2000 ‘Onion World” Magazine.

A transgenic onion plant carries a foreign gene inserted through a biotechnological means.  At least one foreign gene has been put into the plant.  It may be from another closely related plant, bacteria or even an animal.  GMO stands for genetically modified organism and that genetic modification could come from classical or biotechnological means.

Plant breeders have been inserting foreign genes in plants for many years.  We cross the close relatives and we do so using classical plant breeding approaches.  There are many examples around.  Most wheat produced out West, for example, has a small piece of genetic material from rye in it.  Much of the disease resistance in today’s vegetables, especially tomatoes, peppers and potatoes, come from distantly related species.  Hence gene transfer is not new.  What is new is that it is now possible to transfer genes from bacteria, fungi and animals.  They can be inserted into plants to develop new products or cultivars.

A gene is a stretch of DNA containing the recipe for making a protein.

Genes are contained in the cells in all living things.  They guide how living things are made and how they function. They act as codes for different traits which are passed from one generation to the next.  Each gene is responsible for making a particular protein.  Proteins make up the working parts of all plants and animal organisms.  Genes are carried in a chemical called DNA.  Every cell that makes up every plant or animal has its own DNA.

DNA stands for deoxyribonucleic acid, the chemical which carries the information every cell needs in order to do its job.                                                           

History of hybrids

Originally seeds from the most productive, disease resistant plants were saved and planted out to produce better crops.  Then farmers learnt to cross one successful plant with another to produce a hybrid plant with the best qualities of the two plants.  Hybrid crops are made by controlling the pollination of the plant’s flowers, but the plants must be closely related to allow cross-pollination to happen. 

GM Crops 

Agrobacterium method.  The desired gene(better flavour or colour) is identified and cut into the plasmid of a bacterium called Agrobacterium tumefaciens.  This is put in a dish with cells of plant you wish to enhance with a nutrient jelly to keep the cells alive.  The modified cells are encouraged to grow and planted out.  Therefore agrobacterium tumefaciens is a bacterium used to infect plants and carry foreign genes into them.

Microscience.  Some plants cannot be modified as above (e.g. cereals) and genes are coated onto tiny gold pellets, which are then fired (shot from a gene gun) into plant cells.

 

Therefore, with GM crops, scientists cut or fire new genes into a plant’s cells to produce a crop with the desired properties.  GM is a more precise technique because it transfers just the desired gene rather than the many genes that get transferred in traditional cross breeding. 

Animal, vegetable or mineral?  GE could give the game we used to play as children, a new twist!  The issues are complex and now the ground swell of public debate has been heightened by election momentum and the most recent GM Sweetcorn question.    Although media coverage is energetic, offering the reader approaches from many angles, reports are often highly technical, confusing and present contradictory information. It is hard to sort out the basics, when the lines between GE/GM and biotechnology issues blur, organics are mentioned in the same breath and hybridization doesn’t get a mention. 

 

So where do scare mongering and common sense meet? Having the clear answer to a few questions is a good start. Is there a difference between GE and GM and if so, what is it?  What is GMO?  Is it acceptable to consider GE produced medicine (i.e. insulin) OK but not plants or animals?  Why is GE all right if it doesn’t leave the laboratory?  What does the term biotechnology mean?  Where do organics fit in?  What about hybridization?

 

My involvement in the horticultural industry gave me access to some useful definitions.

Finally Dr Pike described GMO as a genetically modified organism and added that genetic modification could come from classical or biotechnological means.

Local research offered an answer to the question regarding whether GE and GM are the same things.  Sources say there is a difference.  Today, GE (Genetic Engineering) really refers to the process, while GM (Genetically Modified) refers to the product.

It was also pointed out that most commercial crops are developed by classical breeding systems, also called genetic modification. This is the manipulation that has been practiced throughout the ages, as gardeners started saving seeds and screened them to achieve new generations of seedlings with improved characteristics as well as selecting related plants for cross-pollination. It could be simply natural breeding selection by observation known as ‘rogueing', that sees plant selection based on a genetic disposition.  A plant is chosen as a parent to breed with a wild or other substitute variety of the same species.

Genetic engineering produces plants and other organisms, through a process using molecular biology, in which genes are incorporated (usually using a bacterium) from another organism into the target plant or animal.  A gene is a stretch of DNA containing the recipe for making a protein. Proteins make up the working parts of all plants and animal organisms. Genes are contained in the cells in all living things and are carried in a chemical called DNA.  Every cell that makes up every plant or animal has it's own DNA.

What is organic food? As defined by a USDA (United Sates Dept of Agriculture) Study Team on Organic Farming, "Organic farming is a production system which avoids or largely excludes the use of synthetically compounded fertilizers, pesticides, growth regulators, and livestock feed additives. To the maximum extent feasible, organic farming systems rely upon crop rotations, crop residues, animal manures, legumes, green manures, off-farm organic wastes, mechanical cultivation, mineral-bearing rocks, and aspects of biological pest control to maintain soil productivity and tilth, to supply plant nutrients, and to control insects, weeds and other pests”.

 

Hence GE and organic are kindred spirits.  For instance, Bio-Gro NZ, New Zealand’s largest organics organization, will not accept any GE content in certified organic produce. We see the word organic attached to many products, but vegetables etc. from organic farms that have not been inspected and passed by an accredited organic certifier cannot be ‘certified organic’.  Certified organic is subjected to strict controls, whereas food simply labeled organic could be less satisfactory than conventional products governed by regulations. Farmers wanting a ‘natural’ fertilizer, choosing blood and bone, may accumulate stockpiles of butchers waste, stored and decomposing in the open  - all parts included.

It is said we are what we eat. We are entitled to know about tampering taking place with the make-up of the food we put on our tables and in turn suspicious of closet manipulation, but many food producers mask undesirable food additives by hiding them as numbers.

E.g. 621 = MSG  GE in relation to health and marketing tool implications is one thing, but without correct and full labeling of all goods on the shelf, the consumer can’t make an honest choice.

These are just answers to very specific questions and not solutions.  But they do broadly outline the  facts and myths about hybrid, GM, GE and organic.

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