SEIJO jose guillermo
capítulos de libros
Genomic characterization of Arachis species by cytogenetics and molecular markers.
LAVIA, G.I; FERNANDEZ, A.; SEIJO, J.G.
Año: 2008; p. 101 - 134
Abstract This chapter aims to integrate the new cytogenetic and molecular data concerning peanut, its secondary/terciary gene pool, and the Arachis species that are being used as forage, with the large existent biosystematic knowledge to afford old and recent questions on the genetic origin of the cultigen, species relationships within Arachis section, the evolutionary relatedness of x=9, and the origin of polyploids of Rhizomatosae and Caulorrhizae sections. The allopolyploid nature of peanut was confirmed having two complements with heterochromatic bands and two without them in all botanical varieties. Gene mapping by FISH, most molecular markers and amphidiploid resynthesis supports A. duranensis and A. ipaensis as the most probable genome donors of A. hypogaea. Moreover, A. monticola is revealed as the wild tetraploid from which peanut derived upon domestication rather than a wild derivative. Although the close relatedness of some species has been established, a clear phylogeny of section Arachis has still to be delineated. Basic chromosome number x=9 may has arisen from x=10 independently in different sections. Rhizomatous species appears as a polyphyletic group in which the diploid A. burkartii seems to have a different genome constitution than the tetraploids. Meiotic behavior of A. pintoi suggests that spontaneous polyploidization in Arachis may occur through unreduced gametes.