Shipoh, Panduleni Mwahepekange2021-07-292021-07-292021http://hdl.handle.net/11070/2985A thesis submitted in fulfillment of the requirements for the Degree of Master of ScienceEndophytic microorganisms are symbionts found inside host tissue without eliciting disease, symptoms or causing any damage. They play an integral role in spermatophyte life cycles and are endowed with multi-functional traits that promote the host’s health, growth and yield. Cleome gynandra L. (C. gynandra), is an unexplored “orphan” plant that has a diverse array of such endophytic microbial populations. C. gynandra (Ombidi in Oshiwambo; Ombowa in Herero; Gomabeb in Damara/Nama) is a neglected droughttolerant wild annual crop spread in semi-arid regions of Northern Namibia. This plant has shown great potential in agronomy, climate adaptation, economy and traditional medicine, making it stand out as a prominent contender among climate-adapted future crops. Little, however, is known about C. gynandra plant growth promoting (PGP) seed endophytes. The study aimed to isolate and identify endophytic bacteria associated with C. gynandra spermatophyte and characterize their functional plant growth promoting potential which could be used to improve plant growth and yield. Twenty morphologically distinct isolates were assessed. They exhibited various abilities to produce growth regulators that contribute to ammonia production (85%), atmospheric nitrogen fixation (40%), fluorescence production (10%), hydrogen cyanide production (30%), indole acetic acid (IAA) production (100%), phosphate solubilization (15%) and siderophore production (80%). Phylogenetic analysis showed that all the isolates (excluding Phytobacter ursingii) belonged to the Proteobacteria phylum. The application of endophytic plant growth promoting bacteria (PGPB) is considered to have the potential for improving plant growth in extreme environments. Three best PGP producing isolates, namely Enterobacter cloacae, Klebsiella pneumoniae and Kluyvera cryocrescens were selected for greenhouse trials using Brassica napus L. (Rape English Giant) seeds. In comparison to the control groups, there was a statistically significant difference for root length (p=0.024), plant height (p=0.037) wet (p=0.000) and dry (p=0.000) mass in the microbial experimental group. This indicated that the microbe treatments had an effect on growth parameters. From this study, it is concluded that C. gynandra seeds harbour a reservoir of endophytic bacteria with the ability to improve plant growth and with the potential for use as inoculants (biofertilizers) to establish sustainable crop production systems.enSeed inoculantsSeed bacteriaPlant growth-promotingEndophytesThesis