The Science Behind Plant Hybridization and Gene Modification

Plant hybridization and gene modifications are methods of bringing changes in the genotype (genetic makeup) and phenotype (gene expression /physical appearance) of a plant. Both these methods are used to produce plants with enhanced good characteristics. 

Contents: 

1. Gene modification
2. Types of gene modifications

1. Selective 
2. Inbreeding
3. Hybridization

• Advantages of hybridization
• Types of hybridization
• Steps to hybridize plants at home

1. Genome editing
2. Genome sequencing

What is Gene modification? 

Gene modification is a group of techniques to bring changes in the genes or DNA of a plant. 

Types of gene modifications: 

There are 3 types of gene modifications.

1. Selective breeding
2. Genome editing
3. Genetic engineering
   

Selective breeding

Selective breeding involves breeding or crossing two plants with desired characteristics, for example, two tall trees, to produce offspring having those desired characteristics i.e. tallness. After a few generations of tall plants being bred together, it may be even possible to produce a plant even taller than the original parental generation. It produces homozygosity in plants. 

What is Inbreeding? 

The first method of selective breeding is “inbreeding”. It is done by breeding two similar parent plants. This kind of breeding is used to conserve genes for the desired characteristics within a population. But at the same time recessive genes like diseases that were not visible in parents, can become active or visible in homozygous offspring. 

What is Plant Hybridization? 

Hybridization, a method of selective breeding, is the process in which two genetically distant organisms (plants) are crossed with each other. This creates a new combination of alleles in the resulting individual. This way variabilities are created in genotypes of the population i.e. homozygosity is reduced. It is done to produce a genotype with desired traits. Plant hybridization or outbreeding can be both natural and artificial. 

Hybrids: Resulting individuals will be called hybrids

Advantages of plant hybridization: 

1. It combines the traits of two distinct plants. 
2. Hybridization produces a heterozygous generation in which favorable traits are selected. Hybridization is especially beneficial in commercially important traits. 
3. Moreover, it brings genetic variability which leads to better chances of survival for resulting individuals. 
4. Another benefit of hybridization is that it results in individuals that are adapted to the selected trait. 

What are the types of hybridization? 

Hybridization can be of two types, 

1. Somatic hybridization
2. Sexual hybridization

Somatic hybridization is a modern technique of fusion of two protoplasts, performed in vitro. Sexual hybridization, on the other hand, is a classic approach with many sexual barriers. 

Examples of hybrids;  

• Sweet corns: Result of naturally occurring mutation in sugar-converting genes
• Pomato: Hybrid produced by grafting a tomato plant with a potato plant
• Sudachi yuzu: a hybrid between Sudachi and Yuzu
• Meyer lemon trees: a hybrid of lemon and orange plants

Scientists have also classified hybridization based on the taxonomic relationship of the parent plants as follows. 

1. Intervarietal or intraspecific hybridization 
2. Distant hybridization

Intervarietal or intraspecific hybridization involves parent plants of the same species but different strains or varieties. Word inter suggests between (two different varieties) and intra suggests within (the same species). Such a cross is commonly used in crop improvement programs. Whereas distant hybridization involves two different species or even different genera.  

Steps to hybridize plants at home 

1. Choose your favorite plants which you want to hybrid. 
2. You need to cross-pollinate these. But before that, select one plant to act as a male and the other to act as a female. 
3. If you are worried about their self-pollination, remove stamens from your female plant. 
4. To cross-pollinate, collect pollen from the stamen of the male plant and sprinkle them on the style of the female plant. 
5. Keep these plants in a separate place away from other plants till it grows fruits. 
6. Take these fruits and harvest them. These fruits are the first hybrids and their seeds will be the F1 generation.
7. Planting F1 generation seeds, you will get your new hybrid plants. 
8. Hybridization will work for compatible plants only and this could be a random process giving unpredictable traits as a result. 

Note: Hybridization doesn’t change the genetic makeup of an individual. It only produces a new combination of genes. Whereas, gene modification is a process of producing changes in the genetic makeup (DNA) of an individual. 

Genome editing 

Gene editing or genome editing News is various techniques of making changes in the genes (adding, deleting, altering) of plants. 

Genetic engineering

Gene modification is also known as genetic engineering or genetic manipulation. As the name suggests it is the method of bringing Genetic variability in plants. It uses techniques and technology to modify or manipulate a plant’s genetic makeup. It is an artificial process where scientists can remove a gene from one plant and transfer it to the other. This transferred gene will show its expression in the new host as well. 

GMOs: Organisms produced as a result of gene modifications or genetic engineering are known as genetically modified organisms (GMOs) or transgenic.

Examples of GMO plants

• Argentine Canola (Brassica napus)
• Cotton (Gossypium hirsutum L.)
• Bean (Phaseolus vulgaris)
• Apple (Malus x Domestica)
• Alfalfa (Medicago sativa)