The Evaluation of Root System Architecture (RSA) As A New Breeding Target for Climate-Resilient Winter Wheat (Tritium aestivum L.)

Crop yields are expected to face more threatening circumstances due to ongoing climatic and environmental change. The continued sustainability of crop production will depend on genetic capacity of crops to adapt to increased biotic and abiotic barriers induced by climate change. Historically, shoot-based traits were breeding targets for overcoming yield gaps between developed and undeveloped nations. However, the rate of genetic gain has stabilized with conventional breeding targets for indirect yield improvement. As the availability of mineral fertilizers is steadily declining and the occurrence of low-fertility soils has increased, reoccurring yield disparities worldwide are propelling us to evaluate new breeding targets. There is potential for plant breeders to shift their focus to the root system architecture (RSA) as a new target for indirect selection, enabled by the phenotypic plasticity of winter wheat (Triticum sp.), one of the main staple agronomic crops. Our current limited understanding of the dynamic nature of the root system architecture is due to the difficulties associated with in situ phenotyping and characterization of anatomical traits. The objectives of this thesis were to 1) review advancements in root phenotyping methodologies and past, present, and future predictions; 2) evaluate differences in root biomass accumulation and remobilization among 22 Virginia Tech-developed elite germplasm; 3) evaluate potential genetic variability for root biomass accumulation across breeding lines. Minimal genetic variation was observed for root biomass accumulation through time. Soil coring proved not to be a very effective method for capturing genetic variability of root biomass accumulation from a soil depth of 10 cm. However, a low genetic signal was also observed for shoot biomass, even though the entire field plot for each genotype was sampled. Yet, a considerably higher genetic signal was observed for plant height. These results suggest that both root and shoot biomass are complex, polygenic traits that require significantly more attention to evaluate genetic differences.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Crop and Soil Environmental Sciences

Department dc:contributor.department

Crop and Soil Environmental Sciences

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2024

Author dc:creator

• Ragland, Demetrius Isaiah

Chair dc:contributor.committeechair

• Santantonio, Nicholas

Committee members dc:contributor.committeemember

• Possinger, Angela Ruth
• Bargmann, Bastiaan

• Root System Architecture (RSA)
• Climate Resiliency
• Winter Wheat (Tritium aestivum L.)
• Accumulation
• Remobilization

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

vt_gsexam:41472

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/121375