Impact of Molecular Genetic Research on Peanut Cultivar Development

Abstract

Peanut (Arachis hypogaea L.) has lagged other crops on use of molecular genetic technology for cultivar development in part due to lack of investment, but also because of low levels of molecular polymorphism among cultivated varieties. Recent advances in molecular genetic technology have allowed researchers to more precisely measure genetic polymorphism and enabled the development of low density genetic maps for A. hypogaea and the identification of molecular marker or QTL's for several economically significant traits. Genomic research has also been used to enhance the amount of genetic diversity available for use in conventional breeding through the development of transgenic peanut, and the creation of TILLING populations and synthetic allotetraploids. Marker assisted selection (MAS) is becoming more common in peanut cultivar development programs, and several cultivar releases are anticipated in the near future. There are also plans to sequence the peanut genome in the near future which should result in the development of additional molecular tools that will greatly advance peanut cultivar development.

Groundnut improvement: use of genetic and genomic tools

“…QTL analysis was used for identification of QTLs for several important traits such as drought tolerance related traits (Varshney et al, 2009; Ravi et al, 2011; Gautami et al, 2012), resistance to foliar disease (Khedikar et al, 2010; Mondal et al, 2012; Sujay et al, 2012), and nutritional quality traits (Chen et al, 2010; Chu et al, 2011; Sarvamangala et al, 2011) were reported. The availability of genomic resources such as molecular markers, genetic and physical maps, expressed sequence tags (ESTs), mutant resources, and functional genomics platforms that facilitate the identification of QTLs and discovery of genes associated with tolerance/resistance to abiotic and biotic stresses and agronomic traits was reviewed (Holbrook et al, 2011; Pandey et al, 2012b). Identification of target markers to traits of economic importance has enabled integration of molecular breeding in groundnut improvement as will be discussed in the following section.…”

“…The progress made when molecular breeding was integrated with conventional procedures in development of improved groundnut varieties was quite impressive. Holbrook et al (2011) reviewed the impact of molecular genetic research, both genomic and transgenic tools on groundnut cultivar development. In this section we dwell upon some examples of its successful deployment.…”

Genomic regions associated with resistance to peanut bud necrosis disease (PBND) in a recombinant inbred line (RIL) population

“…When reliable and cost‐effective markers are developed, marker‐assisted breeding (MAB) offers considerable advantages in terms of early generation selection and possible optimization of time and resources. MAB has been successfully deployed in peanut to introgress QTL governing resistance to foliar fungal diseases (rust and late leaf spot) into three popular cultivars belonging to early maturity group (Janila et al, ; Varshney et al, ) and also for transferring the high oleic trait to elite lines (Chu et al, ; Holbrook, Ozias‐Akins, Chu, & Guo, ; Janila et al, ). The identification of markers linked to the trait of interest is the base to develop markers for use in MAB.…”

Efeito da alotetraploidização em espécies silvestres de Arachis e mapeamento de QTLs de resistência à ferrugem (Puccinia arachidis Speg.) em população F6 de genoma B

“…e a mancha-preta, causada pelo Phaeoisariopsis personata Ber. e MA Curtis, são doenças do amendoim economicamente muito importantes, podendo causar juntas perdas de 50-70% na produção da cultura, quando não controladas (Subrahmanyam et al, 1985;Holbrook, et al, 2011).…”

“…Nesse sentido, estudos têm documentado que essas espécies apresentam alto grau de polimorfismo de DNA (Moretzsohn et al, 2009), além de fontes de resistência quanto à imunidade e resistência a manchas foliares e ferrugem (Subrahmanyam et al, 1985;Bertioli et al, 2003). Grandes esforços têm sido feitos para o desenvolvimento de ferramentas genéticas e genômicas em amendoim, como o desenvolvimento de populações de mapeamento, fenotipagem apropriada, marcadores moleculares, identificação de QTLs (Quantitative Trait Loci), e marcadores ligados a diversas características importantes (Hong et al, 2010;Holbrook et al, 2011;Sujay et al, 2012;Pandey et al, 2012;Varshney et al, 2013). Apesar de existirem QTLs de resistência à ferrugem em populações geradas a partir de cultivares (Khedikar et al, 2010), a genética para resistência à ferrugem ainda não foi completamente elucidada.…”