Niche modelling supports the origin of peanut in the orchards of ancient inhabitants

SEIJO JG; PÉREZ L; MORENO S; CHALUP L.; SAMOLUK SS; ROBLEDO G.

Córodoba

Conferencia; 9th International Conference of the Peanut Research Community- AAGB 2017; 2017

Arachis duranensis (A genome) and A. ipaënsis (B genome) are, respectively, the maternal and paternaldiploid genome donors of peanut and A. monticola(4x, AABB). Two hypotheses were proposed concerning the scenario of the originof tetraploids, 1) spontaneous hybridization in natural environments, for whichsympatric distribution of diploid parents is needed and, 2) ancient peopleused, moved and cultivated wild species, giving a chance to the progenitors ofpeanut to get in sympatry in their orchards. The only one known population of A.ipaënsis lives at the north limit of A.duranensis distribution, but the former species lives in an unexpectedenvironment far from its phylogenetically closest species (A. magna) and from any of the other species withthe B genome. In this work we modeled the present and past (22000 YBP,LMG)species distributions to test the natural occurrence of A. duranensis in sympatry with any  of the B genome species. All the known localitiesfor A. duranensis, and all the B genomespecies (excluding A. ipaënsis) wereincluded in the analysis. Modellingevidenced that it is largely improbable that any of the B genome species wouldbe sympatrically distributed with A.duranensis at present. In the past, and considering only the points for A. magna, there is a low probability (0- 25%) that this species overlapped with A.duranensis in a restricted area in the South of Bolivia. This probability decreasedto cero when all the B genome species were considered in the analysis. Althoughour results are not conclusive, the analysis here performed added data tosupport an anthropic influence in the origin of peanut.