ROOT ANATOMICAL CHARACTERISTICS OF A SEGREGATING SWITCHGRASS POPULATION

Undergraduate #150
Discipline: Biological Sciences
Subcategory: Plant Research
Session: 3
Room: Exhibit Hall A

Bacari Harris - Fort Valley State University
Co-Author(s): Joel Reyes-Cabrera and Felix B. Fritschi

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Switchgrass (Panicum virgatum L.) is championed as the primary perennial crop for lignocellulosic biomass production in the U.S. It is native to North America and forms a sod with abundant tillers that can grow up to 3 m tall, and has two ecotypes with distinct morphological traits: “upland”, which is adapted to drier environments, and “lowland” which is adapted to wetter environments. While there is abundant information about switchgrass aboveground traits, our understanding of belowground dynamics is rudimentary. Therefore, the objective of this study was to evaluate root anatomical traits of a switchgrass mapping population generated by first crossing the lowland ‘Alamo’ with the upland ‘Dacotah’, and the lowland ‘West Bee Cave’ with the upland ‘Summer’ ecotypes. The resulting F1 where then crossed with each other to produce the parent of the four-way population. The population of 797 lines was planted at the Bradford Research Center near Columbia, MO in 2015, and root core samples were collected following biomass harvest in 2016. Roots in core samples were washed free from soil and a section of transport root was excised and preserved in formaldehyde alcohol acetic acid until further processing. Root cross sections were manually cut, stained with Toluidine Blue, and imaged at 5x magnification on a microscope (Leica DM 5500). Root cross sections images were used to measure root diameter, xylem and phloem vessel number, pericycle diameter, cortex diameter, epidermis width, and stele diameter. This study revealed significant genetic variation in transport root anatomy within the mapping population. Results will be used for mapping of genomic regions underlying anatomical characteristics and will lead to a better understanding of the genetics controlling these characteristics.

Funder Acknowledgement(s): NSF ; REU ' Dr. Sharp, (University of Missouri Columbia)

Faculty Advisor: Felix Fritschi, fritschif@missouri.edu

Role: Analyze Samples