Study of the Evolution of Cultivated Peanut through Crossability Studies among Arachis ipaënsis, A. duranensis, and A. hypogaea

Genus Arachis L. includes 80 described species, of which 31 belong to section Arachis, including the two diploid species A. ipaënsis Krapov. and W.C. Gregory and A. duranensis Krapov. and W.C. Gregory, considered the putative B and A genome parents of the cultivated peanut. This work contributes to the study of evolution of the peanut (Arachis hypogaea L.), based on the successful hybridization between A. ipaënsis and A. duranensis, chromosome doubling of the hybrid, and crosses between the synthetic amphidiploid and representatives of the diversity of the crop. Diploid hybrids between A. ipaënsis and A. duranensis, confirmed by molecular markers, had pollen stains of 0.98%. Colchicine-induced tetraploids were confirmed by mitotic chromosome counts. Progeny from these amphidiploid plants had a 97.74% pollen stain and significant differences among structure sizes measured in diploid and tetraploid flowers. Hybrid individuals [A. hypogaea x (A. ipaënsis x A. duranensis)4x] were produced from crosses involving all six botanical varieties of A. hypogaea. These hybrids indicate the evolutionary similarity between the wild species and the cultigen. The successful hybridization between diploid species A. ipaënsis and A. duranensis and between A. hypogaea and the synthetic amphidiploid support the theory that these two diploids are the parents of the cultivated peanut. Resulting materials are of great importance to peanut breeding.