Evaluation of pesticide effects on bean and sesbania rhizobia and their symbiotic relationship
| dc.contributor.author | Baijukya, Frederick Philbert | |
| dc.date.accessioned | 2026-07-22T11:20:11Z | |
| dc.date.available | 2026-07-22T11:20:11Z | |
| dc.date.issued | 1996 | |
| dc.description | Dissertation | |
| dc.description.abstract | Laboratory and glasshouse experiments were conducted at the Sokoine University of Agriculture, Morogoro, to evaluate the effects of kocide 101 (77% cupric hydroxide) a fungicide and oxadiazon [3-(2,4-dichloro-5(l- methylethoxyphenyl)-5-(1 ,1 -dimethylethyl-1,3,4-oxadiazol-2(3 H)-one] a herbicide, on the growth and symbiotic performance of bean (Phaseolus vulgaris L.) and Sesbania rostrata rhizobia, respectively. The growth of the rhizobial strains in the presence of the pesticides was evaluated in Yeast Mannitol Broth (YMB). The \eg\i.vne-Rhizobium symbiosis was evaluated in the glasshouse using a sandy loam soil (Typic Rhodustalf) for beans and a clay soil (Udic Ustifluvent) for Sesbania. Kocide 101 in the broth medium inhibited growth of rhizobia. Of the three strains tested for sensitivity to kocide 101, the local isolate was most tolerant followed by the PV] strain, and the strain CI AT 899 was least tolerant. The growth of Sesbania rhizobia in broth medium was unaffected by the addition of oxadiazon. The application of kocide 101 at the recommended application rate (equivalent to 1.7 mg/kg soil) had no harmful effect on growth, nodulation and nitrogen fixation of bean plants. Kocide 101 applied at 2x and 4x the recommended application rate (equivalent to 3.4, and 6.8 mg/kg soil) was detrimental to the growth, nodulation and N2 fixation. The inhibition of nodulationiii and N2 fixation in the presence of kocide 101 was mainly due to the direct effect of the fungicide on the bean plants. The application of oxadiazon at the recommended application rate, at 2x and at 4x the recommended application rate (equivalent to 0.75, 1.50, and 3 mg/kg soil, respectively) adversely affected the growth, nodulation and N2 fixation by Sesbania rostrata plants, the inhibition increasing with increase in oxadiazon concentration. The inhibition in nodulation and N, fixation in the presence of oxadiazon was, to a large extent, due to adverse effects of the herbicide on plant growth and development rather than on rhizobial viability. Nodule formation and plant growth of both beans and Sesbania continued to be curtailed by the pesticides residues four months after they were first applied to the soil. | |
| dc.description.sponsorship | Norwegian Agency for International Development (NORAD) | |
| dc.identifier.uri | https://www.suaire.sua.ac.tz/handle/20.500.14820/7812 | |
| dc.language.iso | en | |
| dc.publisher | Sokoine Univesirty of Agriculture | |
| dc.subject | Symbiotic relationship | |
| dc.subject | Glasshouse experiments | |
| dc.subject | Pesticide effects | |
| dc.subject | Sesbania rhizobia | |
| dc.title | Evaluation of pesticide effects on bean and sesbania rhizobia and their symbiotic relationship | |
| dc.type | Thesis |