Pollen DNA barcoding is the process of identifying pollen donor plant species through the amplification and sequencing of specific, conserved regions of plant DNA. Being able to accurately identify pollen has a wide range of applications though it has been difficult in the past due to the limitations of microscopic identification of pollen.

Pollen identified using DNA barcoding involves the specific targeting of gene regions that are found in most to all plant species but have high variation between members of different species. The unique sequence of base pairs for each species within these target regions can be used as an identifying feature.

The applications of pollen DNA barcoding range from forensics, to food safety, to conservation. Each of these fields benefits from the creation of plant barcode reference libraries. These libraries range largely in size and scope of their collections as well as what target region(s) they specialize in.

One of the main challenges of identifying pollen is that it is often collected as a mixture of pollen from several species. Metabarcoding is the process of identifying the individual species DNA from a mixed DNA sample and is commonly used to catalog pollen in mixed pollen loads found on pollinating animals and in environmental DNA (also called eDNA) which is DNA extracted straight from the environment such as in soil or water samples.

Some of the principle constraints of microscopic identification are the expertise and time requirements. Identifying pollen via microscopy requires a high level of expertise in the pollen characteristics of the specific plants being studied. With expertise it can still be extremely difficult to identify pollen accurately with high taxonomic resolution. The skills required to do DNA barcoding are much more common making the approach easier to adopt. Pollen DNA barcoding is a technique that has grown in popularity due to the decreased costs associated with "next generation sequencing" (NGS) techniques and is being continually improved in efficiency including through the use of a dual-indexing approach. Some of the other major advantages include the savings in time and resources compared to microscopic identification. Identifying pollen is time-consuming, involving spreading pollen on a slide, staining the pollen to improve visibility, then focusing in on individual pollen grains and identifying them based on size, shape, as well as the shape and number of pores. If a pollen reference library is not available, then pollen has to be collected from wild specimens or from herbarium specimens and is then added to a pollen reference library.

Rare plants visited by some pollinators can be difficult to determine, by using pollen DNA barcoding researchers can uncover "invisible" interactions between plants and pollinators.

There are many challenges when it comes to genetic barcoding of pollen. The amplification process of DNA can mean that even small pieces of plant DNA can be detected included those from contaminants to a sample. Strict procedures to prevent contamination are important and can be facilitated by the hardiness of the pollen coat allowing the pollen to be washed of contaminants without damaging the internal pollen DNA.

DNA barcode reference libraries are still being built and standardized target regions are being gradually adopted. These challenges are likely due to the newness of DNA barcoding and will likely improve with the wider adoption of DNA barcoding as a tool used by taxonomists.