|PRINCE, SILVAS - Noble Research Institute|
|HERNANDEZ, TIM - Noble Research Institute|
|TAYEH, NADIM - Noble Research Institute|
|ANOWER, ROKEBUL - Noble Research Institute|
|Samac, Deborah - Debby|
|BLANCAFLOR, ELISON - Noble Research Institute|
|MOTES, CHRISTY - Noble Research Institute|
|MONTEROS, MARIA - Noble Research Institute|
Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/28/2017
Publication Date: 1/13/2018
Citation: Prince, S., Hernandez, T., Tayeh, N., Anower, R., Samac, D.A., Blancaflor, E., Motes, C., Monteros, M.J. 2018. Genomic and phenomic approaches to understand root growth and development for alfalfa improvement. Plant and Animal Genome Conference Proceedings. January 13-18, 2018, San Diego, California.
Technical Abstract: The plant root system architecture (RSA) affects the capacity for nutrient and water uptake. Certain root traits are favorable under specific abiotic stress conditions and can enhance the performance, productivity and persistence of perennial legume forage species including alfalfa. The objectives of this study were to identify key root traits that result in increased biomass production in alfalfa and to discover the underlying genes for these traits. Field-based evaluations were used to select three alfalfa populations contrasting for branched vs. tapped roots that were part of a genome-wide association study. The RSA of alfalfa seedlings from two additional segregating populations were used to identify specific root traits associated with increased biomass production. The individuals from all three populations were genotyped using genotyping-by-sequencing (GBS) to identify quantitative trait loci (QTL) for root growth and to determine shifts in allele frequencies in key genes. Differences in the root anatomical traits, cortex cell file number and size were also identified using microscopy-based analyses. Further field-based evaluations of alfalfa populations with contrasting root traits planted at different planting densities and grown under irrigated vs. rain-fed conditions provided additional insights on the beneficial root ideotypes to increase alfalfa productivity under different management strategies. The identification of the genetic determinants underlying beneficial root traits can facilitate the implementation of genomics-based approaches in alfalfa breeding programs to increase productivity and persistence.