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ARS Home » Plains Area » Mandan, North Dakota » Northern Great Plains Research Laboratory » Research » Publications at this Location » Publication #368676
Research Project: Sustainable Agricultural Systems for the Northern Great Plains

Location: Northern Great Plains Research Laboratory

Title: Impact of defoliation on axillary bud activity in smooth brome (Bromus inermis Leyss.)

Author
item Hendrickson, John
item Yeoman, Vanessa
item FIELD, AARON - Chadron State College
item Carrlson, Andrew

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/12/2019
Publication Date: 2/16/2020
Citation: Hendrickson, J.R., Yeoman, V.L., Field, A., Carrlson, A.J. 2020. Impact of defoliation on axillary bud activity in smooth brome (Bromus inermis Leyss.). Meeting Abstract. 1.

Interpretive Summary:

Technical Abstract: Smooth brome (Bromus inermis Leyss.) is an introduced cool-season perennial grass that invades rangelands in the Northern and Central Great Plains. Anecdotal data suggests smooth brome may be less abundant when grazed. However, the morphological stage at which grazing can have the greatest impact on smooth brome abundance is unknown. Therefore, we designed a study to determine the impact of defoliation on specific morphological stages of smooth brome. Treatments were 1) defoliated at the 1 or 3 leaf vegetative stage once (V1); 2) defoliated at the 1 or 3 leaf vegetative stage twice (V2); 3) defoliation in the elongation stage (E); 4) defoliation in the reproductive stage (R ) and 5) a non-defoliated control (C ). Ten smooth brome plants were randomly located and permanently marked in each of 4 non-grazed exclosures at the Northern Great Plains Research Laboratory (USDA-ARS) near Mandan, North Dakota in May 2018. In September, each of the tillers were dug up and taken to a laboratory at Chadron State College, Chadron, Nebraska. Each tiller was dissected, all crown positions were identified as 1) axillary bud, 2) tiller, 3) rhizome, 4) leaf scar or 5) missing. Tillers were placed in stains to determine activity. Active meristematic tissue would stain red in 0.1% TTC, dead meristematic tissue would stain blue and if meristematic tissue did not stain in either solution, they were considered dormant. There were fewer active rhizomes per tillers in the V2 treatment than in the C, E and R treatments (0.33 vs 0.96, 0.94 and 0.96 respectively). Total outgrowth (rhizomes and daughter tillers) per tiller was less in the V2 (1.3) than in the R (1.9) treatment. Additional data is being collected but defoliating smooth brome tillers twice in the vegetative stage appears to best strategy to reduce potential recruitment in this invasive grass.