U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska

 

Genetic mapping and QTL analysis for peanut smut resistance

Francisco J. de Blas, Universidad Nacional de Córdoba
Cecilia I. Bruno, FCA – UNC
Renee S. Arias, USDA ARS National Peanut Research Laboratory
Carolina Ballén-Taborda, University of Georgia
Eva Mamani, Instituto Nacional de Tecnología Agropecuaria, Manfredi
Claudio Oddino, Universidad Nacional de Rio Cuarto
Melina Rosso, Criadero El Carmen
Beatriz P. Costero, Universidad Nacional de Córdoba
Marina Bressano, FCA-UNC
Juan H. Soave, Criadero El Carmen
Sara J. Soave, Criadero El Carmen
Mario I. Buteler, Criadero El Carmen
J. Guillermo Seijo, Instituto de Botanica del Nordeste
Alicia N. Massa, USDA ARS National Peanut Research Laboratory

Document Type Article

Abstract

Background: Peanut smut is a disease caused by the fungus Thecaphora frezii Carranza & Lindquist to which most commercial cultivars in South America are highly susceptible. It is responsible for severely decreased yield and no effective chemical treatment is available to date. However, smut resistance has been identified in wild Arachis species and further transferred to peanut elite cultivars. To identify the genome regions conferring smut resistance within a tetraploid genetic background, this study evaluated a RIL population {susceptible Arachis hypogaea subsp. hypogaea (JS17304-7-B) × resistant synthetic amphidiploid (JS1806) [A. correntina (K 11905) × A. cardenasii (KSSc 36015)] × A. batizocoi (K 9484)4×} segregating for the trait. Results: A SNP based genetic map arranged into 21 linkage groups belonging to the 20 peanut chromosomes was constructed with 1819 markers, spanning a genetic distance of 2531.81 cM. Two consistent quantitative trait loci (QTLs) were identified qSmIA08 and qSmIA02/B02, located on chromosome A08 and A02/B02, respectively. The QTL qSmIA08 at 15.20 cM/5.03 Mbp explained 17.53% of the phenotypic variance, while qSmIA02/B02 at 4.0 cM/3.56 Mbp explained 9.06% of the phenotypic variance. The combined genotypic effects of both QTLs reduced smut incidence by 57% and were stable over the 3 years of evaluation. The genome regions containing the QTLs are rich in genes encoding proteins involved in plant defense, providing new insights into the genetic architecture of peanut smut resistance. Conclusions: A major QTL and a minor QTL identified in this study provide new insights into the genetic architecture of peanut smut resistance that may aid in breeding new varieties resistant to peanut smut.