Species, genomes, and section relationships in the genus Arachis (Fabaceae): a molecular phylogeny

New hybrids from peanut (Arachis hypogaea L.) and synthetic amphidiploid crosses show promise in increasing pest and disease tolerance

“…& W.C. Gregory (Robledo and Seijo, 2010). This new classification is supported by systematic molecular studies on the genus Arachis (Bechara et al, 2010;Friend et al, 2010;Wang et al, 2010).…”

Genetic and geographic origin of domesticated peanut as evidenced by 5S rDNA and chloroplast DNA sequences

“…On the other hand, PCR amplified fragment length polymorphism (AFLP) data have shown that at least three diploid species with the A genome and three with the non-A genome have small genetic distance compared with the cultigen whereas microsatellite markers have revealed that, although A. duranensis and A. ipae¨nsis are closely related to the cultigen, a small group of other species having the A or non-A genomes could also be possible genome donors (Moretzsohn et al 2004). Likewise, the inferences made on the relationships between the allopolyploids (A. monticola and peanut) and between them and the wild diploid species using ITS and 5.8 rDNA sequences are limited, because of the polytomies obtained in the dendrograms (Friend et al 2010;Bechara et al 2010;Wang et al 2010). Those interpretations were also hampered because the sequences obtained from the tetraploids could have represented only one of the genomes or may have even been a mixture of the sequences from both genomes, as pointed out by Bechara et al (2010).…”

“…Moreover, it can be a very powerful tool for analysis of single versus multiple origin of tetraploids and investigating their geographic origin (Soltis and Soltis 1989). Although one intergenic region (trnL-trnT) of the chloroplast genome has already been used in the genus with phylogenetic purposes (Tallury et al 2005;Friend et al 2010), the polytomies found in the trees recovered from that analysis prevented identification of the exact species donors of the A and B genomes present in the tetraploids of section Arachis. It is expected that better screening for a more appropriate region within the chloroplast genome would provide a useful tool for investigation of the genetic (maternal lineage) and geographic origin of the peanut.…”

The Value of Diploid Peanut Relatives for Breeding and Genomics

“…Although there have been differences observed among marker systems regarding species relationships, and there remain questions about species positions in sectional groupings (Friend et al, 2010), the molecular data generally fits the sectional relationship model proposed by Krapovickas and Gregory (1994). For example, Hoshino et al (2006) used microsatellites to evaluate species in the nine peanut sections, and while most species grouped as expected, several species in the Procumbentes grouped with species from section Erectoides, and others clustered into sections Trierectoides and Heteranthae.…”

“…Galgaro et al (1998) also indicated that species in section Heteranthae did not group together. Friend et al (2010) conducted a more comprehensive investigation of Arachis species and found that sections Extranervosae, Triseminatae, and Caulorrhizae each separated into distinct groups based on trnT-trnF sequences; but species in sections Erectoides, Heteranthae, Procumbentes, Rhizomatosae, and Trierectoides formed a major lineage. Species in section Arachis grouped into two major clades, with (i) the B (renamed the B, F, and K genomes), the D genome species, and 18-chromsome aneuploids being in one group and (ii) the A genome species being in the second group.…”