Genetic Mapping of Persistence in Tetraploid Alfalfa
2008
Robins, Joseph G. | Hansen, Julie L. | Viands, Donald R. | Brummer, E Charles
Persistence is a critical trait for alfalfa (Medicago sativa L.), yet the genetics of this trait are 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, IA, and one production season at Ithaca, NY. Quantitative trait loci (QTLs) underlying persistence were mapped using this population utilizing 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 QTLs, genotype × environment interaction and location-specific QTLs suggest location-specific genetic mechanisms for alfalfa persistence. Nevertheless, in some instances, the same QTLs were identified in different years at the same location. Quantitative trait loci on linkage groups (LGs) 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. Of particular interest was the identification of simple sequence repeat allele al37288-1a1, which associated positively with persistence in each environment of the study.
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