Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/27/2008
Publication Date: 9/23/2008
Citation: Robins, J.G., Hansen, J.L., Viands, D.R., Brummer, E.C. 2008. Genetic Mapping of Persistence in Tetraploid Alfalfa. Crop Science. 48:1780-1786. Interpretive Summary: Genetic determinants of alfalfa persistence were identified in a cross between sativa and falcata type alfalfa using a multi-location study over three production years - Ames and Nashua, IA and Ithaca, NY. Quantitative trait loci (QTL) underlying persistence were mapped and the importance of genetic, as compared to other effects - on the inheritance of persistence was determined. Putative QTL were mapped to linkage groups 1, 2, and 7.
Technical Abstract: Persistence is a critical trait for alfalfa, yet the genetics of this trait is poorly understood. Herein, we characterize an F1 alfalfa population derived from the cross between the two cultivated alfalfa subpecies for persistence in three production seasons at Ames and Nashua, Iowa locations and one production season at Ithaca, New York. Quantitative trait loci (QTL) underlying persistence were mapped employing this population using single-marker analysis and interval mapping procedures. Both parental genomes (Medicago sativa subsp. falcata and M. sativa subsp. sativa) contributed marker alleles associated with persistence, suggesting that alleles from both subspecies have potential for marker-assisted selection. Although, linkage groups 1, 2, and 7 contained putative persistence QTL, genotype x environment interaction and location-specific QTL suggest location-specific genetic mechanisms for alfalfa persistence. Nevertheless, in some instances the same QTL were identified in different years at the same location. QTL on linkage groups (LG) 1 and 2 were location-specific for the Ithaca and Ames locations, respectively. The majority of alleles on LG 7 associated with persistence also exhibited association with biomass production and suggest common genetic determinants for both traits.