Response of Striga-susceptible and Striga-resistant sorghum genotypes to soil phosphorus and colonization by an arbuscular mycorrhizal fungus Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/79408135z

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • Striga, a genus of obligate parasitic weeds in the family Orobanchaceae, has been identified as the most important biological factor limiting agricultural productivity in sub-Saharan Africa. Germination of Striga seeds is triggered by strigolactone root exudates from host plants. Strigolactones also induce hyphal branching in arbuscular mycorrhizal (AM) fungi, which are important for plant uptake of phosphorus in low phosphorus soils. Mechanisms of Striga resistance based on reduced strigolactone production may also convey resistance to AM fungi which would require higher inputs of phosphorus fertilizer to attain optimal crop growth. There is evidence for genetic differences in mycorrhizal responsiveness in other grain crops; therefore it is beneficial for breeders to be aware of these differences when developing Striga-resistant sorghum cultivars. This research aims to determine phosphorus and mycorrhizal responsiveness of sorghum genotypes important for or developed by breeders working on Striga resistance. Phosphorus response curves were determined for twelve sorghum genotypes using pasteurized low phosphorus soil amended to achieve four different phosphorus levels. Simple linear regression was performed on root and shoot dry weight data. Results indicate variability in phosphorus responsiveness within Striga resistant and susceptible genotypes. Seven of these genotypes were selected for continued research, which analyzed responsiveness to phosphorous and differences in mycorrhizal responsiveness in relation to reported mechanisms of Striga resistance. Treatments included three levels of phosphorus amendments and the addition of Funneliformis mosseae inoculum. All genotypes were strongly responsive to P amendment when grown without AM fungi and showed a decrease in responsiveness to P when inoculated with F. mosseae. Trends for all genotypes indicate a greater uptake of P, Zn, and Mg by mycorrhizal plants as compared to nonmycorrhizal plants. All seven genotypes were responsive to mycorrhizae, with a significant increase in biomass for all genotypes, especially at the lowest phosphorus level. The responsiveness to the mycorrhizal fungus does not appear to be directly related to the susceptibility of genotypes to the parasitic weed Striga.
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Non-Academic Affiliation
Keyword
Subject
Rights Statement
Peer Reviewed
Language
Replaces
Additional Information
  • description.provenance : Made available in DSpace on 2012-05-31T22:07:11Z (GMT). No. of bitstreams: 3 LeytemAliciaB2012.pdf: 2860687 bytes, checksum: cc63cf9d16f4a6b63e97a12cc2796148 (MD5) license_rdf: 23457 bytes, checksum: 4a5c7b919ee3cd4f4b33a0bb0951de6b (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2012-05-11
  • description.provenance : Submitted by Alicia Leytem (leytema@onid.orst.edu) on 2012-05-26T01:00:58Z No. of bitstreams: 3 LeytemAliciaB2012.pdf: 2860687 bytes, checksum: cc63cf9d16f4a6b63e97a12cc2796148 (MD5) license_rdf: 23457 bytes, checksum: 4a5c7b919ee3cd4f4b33a0bb0951de6b (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
  • description.provenance : Approved for entry into archive by Julie Kurtz(julie.kurtz@oregonstate.edu) on 2012-05-31T01:06:18Z (GMT) No. of bitstreams: 3 LeytemAliciaB2012.pdf: 2860687 bytes, checksum: cc63cf9d16f4a6b63e97a12cc2796148 (MD5) license_rdf: 23457 bytes, checksum: 4a5c7b919ee3cd4f4b33a0bb0951de6b (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
  • description.provenance : Approved for entry into archive by Laura Wilson(laura.wilson@oregonstate.edu) on 2012-05-31T22:07:11Z (GMT) No. of bitstreams: 3 LeytemAliciaB2012.pdf: 2860687 bytes, checksum: cc63cf9d16f4a6b63e97a12cc2796148 (MD5) license_rdf: 23457 bytes, checksum: 4a5c7b919ee3cd4f4b33a0bb0951de6b (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)

Relationships

In Administrative Set:
Last modified: 08/15/2017

Downloadable Content

Download PDF
Citations:

EndNote | Zotero | Mendeley

Items