RFLP AND CYTOGENETIC EVIDENCE ON THE ORIG IN AND EVOLUTION OF ALLOTETRAPLOID DOMESTICATED PEANUT, ARACHIS-HYPOGAEA (LEGUMINOSAE)

Nuclear restriction fragment length polymorphism (RFLP) analysis was u sed to determine the wild diploid Arachis species that hybridized to f orm tetraploid domesticated peanut. Results using 20 previously mapped cDNA clones strongly indicated A. duranensis as the progenitor of the A genome of domesticated peanut A. ipaensis and the B genome parent. A large amount of RFLP variability was found among the various accessi ons of A. duranensis, and accessions most similar to the A genome of c ultivated peanut were identified. Chloroplast DNA RFLP analysis determ ined that A. duranensis was the female peanut of the original hybridiz ation event. Domesticated peanut is known to have one genome with a di stinctly smaller pair of chromosomes (''A''), and one genome that lack s this pair. Cytogenetic analysis demonstrated that A. duranensis has a pair of ''A'' chromosomes, and A. ipaensis does not. The cytogenetic evidence is thus consistent with the RFLP evidence concerning the ide ntity of the progenitors. RFLP and cytogenetic evidence indicate a sin gle origin for domesticated peanut in Northern Argentina or Southern B olivia, followed by diversification under the influence of cultivation .