Field Pea

Field pea (Pisum sativum) derives from the Middle East and was first cultivated roughly 10,000 years ago. Like the other major crop species originating from this area, including barley, oat, lettuce and several wheat species, cultivated pea still has wild relatives (in this case P. sativum, P. fulvum and P. elatius) growing in the areas where it was originally domesticated by Stone Age farmers.

The genus Pisum is perhaps best considered as a species complex, with multiple sub-species which interbreed to different degrees. In support of this, there is extensive sharing of molecular markers between all Pisum species, suggesting that there has been significant outcrossing between these supposed species, despite the predominantly inbreeding nature of the Pisum genus (greater than 99% of offspring typically derived from self-crossing), which restricts gene flow.

Most wide crosses within field pea are fertile, the exceptions mainly involving P. fulvum and the other species. P. fulvum also forms a distinct clade in all molecular diversity analyses and is the only realistic candidate in the genus for a distinct species. P. sativum is nested within the diversity of P. elatius in most molecular analyses suggesting that cultivated P. sativum derived mainly from the latter species. Other claimed wild species, such as P. humile and P. abyssinicum have little support from molecular studies.