INVESTIGADORES
SEIJO Jose Guillermo
artículos
Título:
An overview of peanut and its wild relatives
Autor/es:
BERTIOLI, D.J; J. G. SEIJO; FREITAS, F; S.C.M. LEAL BERTIOLI; J.F.M. VALLS; M. MORETZSOHN
Revista:
Plant Genetic Resources
Editorial:
NIAB
Referencias:
Lugar: Cambridge; Año: 2011 vol. 9 p. 134 - 149
ISSN:
1479-2621
Resumen:
Abstract
The legume Arachis hypogaea, commonly known as peanut or groundnut, is a very important
food crop throughout the tropics and sub-tropics. The genus is endemic to South America
being mostly associated with the savannah-like Cerrado. All species in the genus are unusual
among legumes in that they produce their fruit below the ground. This profoundly influences
their biology and natural distributions. The species occur in diverse habitats including grasslands,
open patches of forest and even in temporarily flooded areas. Based on a number of
criteria, including morphology and sexual compatibilities, the 80 described species are arranged
in nine infrageneric taxonomic sections. While most wild species are diploid, cultivated peanut is
a tetraploid. It is of recent origin and has an AABB-type genome. The most probable ancestral
species are Arachis duranensis and Arachis ipae¨nsis, which contributed the A and B genome
components, respectively. Although cultivated peanut is tetraploid, genetically it behaves as a
diploid, the A and B chromosomes only rarely pairing during meiosis. Although morphologically
variable, cultivated peanut has a very narrow genetic base. For some traits, such as disease and
pest resistance, this has been a fundamental limitation to crop improvement using only cultivated
germplasm. Transfer of some wild resistance genes to cultivated peanut has been
achieved, for instance, the gene for resistance to root-knot nematode. However, a wider use
of wild species in breeding has been hampered by ploidy and sexual incompatibility barriers,
by linkage drag, and historically, by a lack of the tools needed to conveniently confirm hybrid
identities and track introgressed chromosomal segments. In recent years, improved knowledge
of species relationships has been gained by more detailed cytogenetic studies and molecular
phylogenies. This knowledge, together with new tools for genetic and genomic analysis, will
help in the more efficient use of peanut?s genetic resources in crop improvement.