Identification of several small main-effect QTLs and a large number of epistatic QTLs for drought tolerance related traits in groundnut (Arachis hypogaea L.) uri icon

abstract

  • Cultivated groundnut or peanut (Arachis hypogaea L.), an allotetraploid (2n = 4x = 40), is a self pollinated and widely grown crop in the semi-arid regions of the world. Improvement of drought tolerance is an important area of research for groundnut breeding programmes. Therefore, for the identification of candidate QTLs for drought tolerance, a comprehensive and refined genetic map containing 191 SSR loci based on a single mapping population (TAG 24 x ICGV 86031), segregating for drought and surrogate traits was developed. Genotyping data and phenotyping data collected for more than ten drought related traits in 2-3 seasons were analyzed in detail for identification of main effect QTLs (M-QTLs) and epistatic QTLs (E-QTLs) using QTL Cartographer, QTLNetwork and Genotype Matrix Mapping (GMM) programmes. A total of 105 M-QTLs with 3.48-33.36% phenotypic variation explained (PVE) were identified using QTL Cartographer, while only 65 M-QTLs with 1.3-15.01% PVE were identified using QTLNetwork. A total of 53 M-QTLs were such which were identified using both programmes. On the other hand, GMM identified 186 (8.54-44.72% PVE) and 63 (7.11-21.13% PVE), three and two loci interactions, whereas only 8 E-QTL interactions with 1.7-8.34% PVE were identified through QTLNetwork. Interestingly a number of co-localized QTLs controlling 2-9 traits were also identified. The identification of few major, many minor M-QTLs and QTL x QTL interactions during the present study confirmed the complex and quantitative nature of drought tolerance in groundnut. This study suggests deployment of modern approaches like marker-assisted recurrent selection or genomic selection instead of marker-assisted backcrossing approach for breeding for drought tolerance in groundnut.
  • Cultivated groundnut or peanut (Arachis hypogaeaL.), an allotetraploid (2n = 4x = 40), is a self pollinatedand widely grown crop in the semi-arid regions ofthe world. Improvement of drought tolerance is animportant area of research for groundnut breeding programmes.Therefore, for the identification of candidateQTLs for drought tolerance, a comprehensive and refinedgenetic map containing 191 SSR loci based on a singlemapping population (TAG 24 9 ICGV 86031), segregatingfor drought and surrogate traits was developed. Genotypingdata and phenotyping data collected for more thanten drought related traits in 2?3 seasons were analyzed indetail for identification of main effect QTLs (M-QTLs)and epistatic QTLs (E-QTLs) using QTL Cartographer,QTLNetwork and Genotype Matrix Mapping (GMM)programmes. A total of 105 M-QTLs with 3.48?33.36% phenotypic variation explained (PVE) were identifiedusing QTL Cartographer, while only 65 M-QTLs with1.3?15.01% PVE were identified using QTLNetwork. Atotal of 53 M-QTLs were such which were identified usingboth programmes. On the other hand, GMM identified 186(8.54?44.72% PVE) and 63 (7.11?21.13% PVE), three andtwo loci interactions, whereas only 8 E-QTL interactionswith 1.7?8.34% PVE were identified through QTLNetwork.Interestingly a number of co-localized QTLs controlling2?9 traits were also identified. The identification offew major, many minor M-QTLs and QTL 9 QTL interactionsduring the present study confirmed the complex andquantitative nature of drought tolerance in groundnut. Thisstudy suggests deployment of modern approaches likemarker-assisted recurrent selection or genomic selectioninstead of marker-assisted backcrossing approach forbreeding for drought tolerance in groundnut

publication date

  • 2011
  • 2011
  • 2011

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