Plant Breeding with Molecular Genetics

Summarised By: Samaira Talati-Parikh

Research Paper: https://pmc.ncbi.nlm.nih.gov/articles/PMC12225679/

Many plants lined up for representation and for breeding

There is no doubt that plants are an essential part of our world. However, when plant breeding

is involved, it opens up doors to endless possibilities. Plant breeding includes selecting parent

plants with desirable qualities and cross-breeding them to develop new varieties of plants that

may have unique characteristics or traits.

Recently, a study was conducted on the impacts of molecular genetics with plant breeding.

This is a process which takes place either in a controlled environment like a greenhouse. Initial

materials needed for the crossing can be selected from either elite varieties [easiest source to use, yet may not contain the best genetic variation for improving plant traits], landraces [better

genetic variation], wild relatives [better genetic variation], or mutant stocks [generated by plant

exposure to chemicals/radiation, which is used for morphological and developmental

phenotypes].

Another factor to be considered is how every plant’s reproductive system functions;

for example, natural self-pollinators like barley and wheat can be bred through line breeding,

where the inbred varieties are made from the directed crossing of contrasting parental lines,

whereas some cross-pollinating crops use hybrid breeding.

‘The breeder’s equation’ allows for the calculation of the genetic gain per unit time in a breeding

program when considering selection accuracy [the ability to select the best traits for a breeding

program], selection intensity [the proportion of tested plants that have been selected to be breed,

depending on factors such as cost and time], genetic variability [genetic diversity that has been

chosen in the breeding program], and time [the interval between each breeding generation, such

as time needed to complete a cross, or grow the resulting plants]. The equation is: genetic gain =

(selection accuracy x selection intensity x genetic variability) / time.

There are four molecular genetic approaches in terms of plant breeding, the first one being

transgenic plant breeding. This is when the DNA of the plants are modified using genetic

engineering, with the aim of introducing a new, non-naturally occurring characteristic to the

plant, which comes from artificially inserted genes [ known as the ‘transgene’]. Outcomes of this

include plants with a higher yield, improved quality, better pest resistance and tolerance to

heat/cold/drought resistance.

The most common approach towards genetically breeding plants is gene editing, tools used such

as TALENs [Transcription Activator-Like Effector Nucleases] and CRISPR-Cas9. Some

examples of gene edited crops are the Calyno soybean, edited to remove genes in fatty acidmetabolism and therefore resulting in soybean oil with healthier fat composition. Another

example is the Sicilian Rouge High GABA tomato, resulting in tomatoes with more GABA,

which is a compound with health benefits. While some may think that gene editing is only

used to add new ones, it is also important to note that its gene editing is also primarily used

to knock out unwanted genes.

The third type of molecular genetic approach is marker assisted selection, which is used in a

larger range of crops. An example of this is cereals, which through market assisted selection can

have quality traits, disease resistance, and abiotic stress tolerance. The best technique used for

this approach is backcrossing [crossing a hybrid back to one of its parents] with molecular

markers [DNA sequences that show whether a specific gene is present]. For marker assisted

selection, the foreground section ensures the desired gene is present, whereas the background

selection removes unwanted DNA from the donor parent. Though, this specific technology has

not reached its full potential yet, there is potential for improvements in the future.

The final approach is known as genomic selection - a method that involves using statistic

models to predict the outcome, performance, and breeding values of plants before they enter field testing. This is especially powerful for breeding in terms of improving complex traits such as the plant’s yield or drought resistance. However, for effective genomic selection, it is essential to

invest in infrastructure that has enough computational power, among other factors. Genomic

selection is important as it makes breeding a faster process, while allowing the breeders to set up

and prepare superior varieties earlier.

Some applications of plant breeding with molecular genetics involve using DNA markers to

identify plants with desirable traits for more accurate selection for breeding, introducing genes

from other species, modifying a plant’s own DNA to develop unique traits, all while maintaining

genetic diversity and furthering knowledge of the world around us.

Plant breeding is a complex, yet amazing way to harness the power of plants to produce desired

results. However, it is important to note that human interference can disrupt the processes of

natural selection!

Works Cited - Plant Breeding with Molecular Genetics

1. Jhansi Rani, S., and R. Usha. “Transgenic Plants: Types, Benefits, Public Concerns and Future.”

2. Journal of Pharmacy Research, vol. 6, no. 8, Aug. 2013, pp. 879–83,

3. https://doi.org/10.1016/j.jopr.2013.08.008.

4. Sharma, Rajiv, et al. “Integrating Molecular Genetics with Plant Breeding to Deliver Impact.”

5. Plant Physiology, Feb. 2025, https://doi.org/10.1093/plphys/kiaf087. Accessed 25 Mar.

6. 2025.

7. “What Is Plant Breeding? | National Association of Plant Breeders (NAPB).”Www.plantbreeding.org, www.plantbreeding.org/about-us/what-is-plant-breeding/.