During breeding of Lentil material, we often use interspecific crosses (i.e. crosses between species) to bring in beneficial traits from wild germplasm. This approach gives us access to a wider source of variation and helps reduce domestication bottle necks in Lens culinaris. The resulting progeny from crossing two different species is collectively known as a Lens interspecific. Any single F1 selected from the interspecific cross and progressed through selfing are then known as an introgression line. See the figure below for a diagrammatic representation of this concept.

Figure: Pedigree Diagram explaining the use of "introgression" and "interspecific". This diagram visually explains the terminology used for an interspecific cross -in this case lamoteii by culinaris. The F1s are collectively referred to as interspecific with a single record in KnowPulse denoting them. Then any individuals selected from the F1 and progressed through selfing are referred to as "introgression".

It is important to note that the Lens interspecific designation is used in KnowPulse as the "species" of an interspecific breeding cross. Specifically, there is a single entry for the cross as a whole. Once an individual is chosen from that cross progeny and progressed, it's species is indicated as Lens introgression. Clearly Lens interspecific is not a "species" in the biological sense but rather acts as a indicator within our site that a given germplasm is in the liminal space between species. This is needed because our underlying data structure requires a single species to be indicated for every germplasm.