Genome size in wild and cultivated peanut germplasm

Abstract

Genome size of 16 species of Arachis L. with x = 10 and three with x = 9 was determined. DNA content (2C) between all diploid species, varies from 2.87 pg in A. retusa to 6.59 pg in A. douradiana. Considering species with 2n = 2x = 20 of all the sections, it suggests that in the evolution of Arachis genome, both increases and diminutions of DNA content would have occurred. Species with greater DNA content are included in sections believed to have a more recent origin, whereas those that contain minor DNA belong to the oldest sections; therefore, we propose genome evolution of Arachis toward higher DNA content. Origin of the basic chromosome number x = 9 is discussed considering genome size variation between species with x = 10 and x = 9. Reduction of the DNA content after the polyploidization would have happened in A. hypogaea.