conventional breeding vs molecular breeding

Conventional breeding

Eight to ten thousand years ago, farmers have been altering the genetic makeup of the crops they grow. Early farmers selected the best looking plants and seeds and saved them to plant for the next season. Initially thousands of years ago corn was found like finger of a hand  but Today, there are hundreds of corn varieties which having various size are available. Conventional plant breeding was the method used to develop new varieties of crops for hundreds of years ago. However, conventional plant breeding can no longer sustain the global demand with the,
1.  Increasing population.2. Decline in agricultural resources such as land and water. 3. Decreasing of the yield curve of the staple crops.4. Thus, new crop improvement technologies should be developed and utilized.

Mutation breeding

1. Validated desirable traits is very important in plant breeding. 2. A few superior traits occasionally arise  through a process called as a mutation.But the natural rate of mutation is very slow.3. Plants were exposed to gamma rays, protons, neutrons, alpha particles, and beta particles to see induced mutations. 4. Chemicals such as sodium azide and ethyl methane sulphonate, were also used to cause mutations. Mutation breeding efforts continue around the world today.

Pure lines and hybrid seed

1. For example parent A is crossed with parent B then after F1 generation hybrid seeds are produced but for pure stable lines there is need of repeated self pollination and selection for near about F6 generations.2. Selection of uniform plants is known as pure line selection.3. selection from the field grown plants is 

known as bulk or mass selection and selection of well documented list of percentage known as pedigree system.4. In hybrid seed technology, two pure lines with complementing traits and are derived from diversely related parents are bred together by hand.5. Then F1 hybrids are tested for hybrid vigor in all agronomic and yield parameters and compared to both parents. he resulting offspring's will usually perform more strongly.

Nonconventional breeding

The field of genetic engineering has developed rapidly due to the greater understanding of DNA. DNA having code from which genes are made.The term genetic engineering is used to describe the process by which the genetic makeup of an organism can be altered using recombinant DNA technology.plant breeders now use molecular marker-assisted selection. 

 To help identify specific genes, scientist use what are called molecular markers. 

 Which are short  sequence of nucleic acid which makes up a segment of DNA. 

 The markers are located near the DNA sequence of the desired gene. 

 Since the markers and the genes are close together on the same chromosome, they tend to stay together as each generation of plants is produced. This is called as genetic linkage. 

 This linkage helps to predict whether a plant will have the desired gene.

Methods used

• DNA Fingerprinting • Marker Assisted Selection (MAS) • Marker Assisted Backcross (MABC) • Marker Assisted Pyramiding • Quantitative Trait Loci (QTL) • Marker Assisted Recurrent Selection(MARS) • Genomic Selection 

DNA fingerprinting is genetics method used for isolating and identification of the base-pair pattern in individual’s DNA.

Molecular breeding (MB) may be defined as the use of genetic manipulation performed at DNA molecular levels to improve characters of our interest in plants and animals.

Marker assisted backcross aims to transfer one or genes of interest from one genetic source to elite breeding line to improve the targeted trait.

Pyramiding is the process of combining multiple genes together into a single genotypes.

QTL study is used in breeding to localize chromosomal region that significantly effect the variation of quantitative trait in the population and introgression of favorable QTLs region in to elite variety.

 
MARS refers to the identification and selection of several genomic regions  for complex traits within a single population.

Genomic selection (GS) is a new approach for improving quantitative traits in large plant breeding populations that uses whole genome molecular markers and combines marker data with phenotypic data in an attempt to increase the accuracy of the prediction of breeding and genotypic values.

Conventional breeding

Limited to exchange between the same or closely realated species

Little or no assurance of any gene combination from the million of crosses generated

Undesirable genes can be transferred with the desirable genes

Non Conventional breeding

Allows the direct transfer of genes between either closely or distantly related species

Crop improvment can be achieved in shorter time

Allows plants to be modified by removing or switching off particular genes