In the soybean nitrogen fixing symbiosis, suboptimal root zone temperatures (RZTs) inhibit the inception and development of nodules, leading to reduced nitrogen fixation and soybean yield. The purpose of this thesis was to evaluate the effects of selected with potential low temperature tolerant strains, originating from the northern areas of the USA, and mutants made from Bradyrhizobium japonicum USDA 110, on soybean nodulation, nitrogen fixation and yield in a short season area with cool spring conditions. Among the 40 B. japonicum strains evaluated, only USDA 30, USDA 31, 532 C and USDA 110 grew well at 15°C. USDA 30 and USDA 31 grew better than 532 C and USDA 110 at 15°C. Mutants Bj 30050--Bj 30059 could not produce lipo-chito-oligosaccharide (LCO) at measurable levels in the absence of genistein. All mutants produced more LCOs than 532 C and USDA 110 at the same temperature and genistein concentration. Temperature and genistein concentration did not affect LCO production dynamics for the following: mutant Bj 30055, 532 C and USDA 110. Both mutant production and identification of low temperature tolerant strains achieved the general objective of improved soybean nitrogen fixation in a cool climate. Inoculation with low temperature tolerant strains (USDA 30, USDA31), or mutants (Bj 30055 and Bj 30058) improved soybean development (increases in leaf area and shoot nitrogen content), nodulation (increases in nodule number and nodule weight), nitrogen fixation and yield relative to inoculation with B. japonicum strain 532 C, the strain currently included in most Canadian soybean inocula.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.38097 |
| Date | January 2001 |
| Creators | Zhang, Hao, 1963- |
| Contributors | Smith, D. L. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Plant Science.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001846654, proquestno: NQ75690, Theses scanned by UMI/ProQuest. |
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