Seed Size in the Archaeobotanical Record

Seed size increase in the archaeobotanical record is frequently taken as an indicator of domestication.  Here, I offer some precautionary comments, based on research I carried out on wild emmer wheat (Triticum dicoccoides).  In wild emmer there is pronounced interpopulation genotypic differentiation for seed size, associated with differences in site productivity; while within population the genotypically coded seed size is reduced phenotypically when conditions are less than optimum (e.g., shallow soil microsites).  Similar patterns occur in domesticated plants, as agronomist Sinnott showed 90 years ago.

Seed size increase in the archaeobotanical record may be either phenotypic or genetic.  If the former, it may reflect cultivation, but not domestication.  Or even if genetic, it could reflect selection of the larger seeded wild genotypes under the high fertility of the cultivated field.