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Research Project: Enhanced Alfalfa Germplasm and Genomic Resources for Yield, Quality, and Environmental Protection

Location: Plant Science Research

Title: Understanding alfalfa root systems and their rold in abiotic stress tolerance

Author
item Monteros, Maria - Samuel Roberts Noble Foundation, Inc
item Prince, Silvas - Samuel Roberts Noble Foundation, Inc
item Anower, Rokebul - Samuel Roberts Noble Foundation, Inc
item Tayeh, Nadim - Samuel Roberts Noble Foundation, Inc
item Samac, Deborah - Debby
item Blancaflor, Elison - Samuel Roberts Noble Foundation, Inc
item Motes, Christy - Samuel Roberts Noble Foundation, Inc
item Hernandez, Tim - Samuel Roberts Noble Foundation, Inc

Submitted to: ASA-CSSA-SSSA Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 9/15/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The root system architecture (RSA) impacts the capacity of the plant for efficient water and nutrient uptake. Root phenes have been associated with productivity under stress conditions and persistence of perennial species. The objectives of this study were to identify root traits that increase productivity under drought stress and determine the genetic determinants underlying these traits in alfalfa (Medicago sativa L. subsp. sativa) using both phenotyping and genotyping approaches. Alfalfa is a perennial, auto-tetraploid, out-crossing species and a major forage crop. Field-based evaluations of diverse germplasm were performed to identify individuals contrasting for root morphology (branched vs. tapped roots) and drought tolerance. Some of these genotypes were further characterized in the greenhouse to assess their root penetration ability under drought stress conditions. The amount of tertiary roots was significantly different between plants with mainly tapped vs. branched roots. Anatomical traits of predominately tapped vs. branched roots including cortical cell size and number and diameter of the root vasculature were also evaluated. Root traits associated with increased biomass production were identified. In parallel, individuals from breeding and mapping populations contrasting for root growth were genotyped using genotyping-by-sequencing to map quantitative trait loci for root growth and to determine shifts in allele frequencies in key genes. Identifying the ideal RSA for different soil types and abiotic stress conditions and unravelling the responsible genes can be used to implement genomics-based breeding approaches to increase alfalfa biomass yield and persistence.