Isolation and Characterization of <i>Striga hermonthica</i> Seed-Bank Depleting Bacteria from <i>Striga</i> Infested Sorghum Growing Areas of Ethiopia

Abstract

<i>Striga hermonthica</i> is a very serios parasitic weed of (<i>Sorghum bicolor </i>L. Moench). It attack host plants by living as hemi-parasite and attaching small sucker root system to host plant. A study was undertaken to evaluate the effect of bacterial isolate obtained from soil samples collected from <i>Striga </i>infested sorghum growing fields in Amhara, Tigray and Oromia Regions to inhibit (deplete) the <i>Striga </i>seed bank. Surface sterilized and conditioned <i>Striga </i>seeds were buried in the soil by using teabag to determine germinated, viable and decayed seeds at different times after burial. A total of 44 isolates were isolated from germinated and decayed striga seeds and tested for their effect on germination and seed decay of <i>Striga </i>seeds. Six isolates (GS29, GS32, GS34, GS39, GS42 and GS45) were stimulated 10.33, 9.0, 9.67, 8.33, 5.33 and 8.33 <i>Striga </i>seeds germination from the total of 35 seeds respectively in the absence of host plant synthetic stimulant. On the other hand four isolates (SD3, SD9, SD36 and SD46) significantly decayed <i>Striga </i>seeds at P<0.05 (21, 20, 21.33 and 21 seeds respectively) in order to reduce <i>Striga</i> attack. Selected isolates were characterized by using biochemical tests, and three isolates were classified under the genus <i>Pseudomonas</i> while the other three isolates were grouped under the genus <i>Klebsiella.</i> The four isolates that showed seed decay were classified under the genus <i>Bacillus</i> morphologically.