Effects of fungal liquid culture aqueous extract and phytohormones on Striga hermonthica (Del.) Benth. germination

Abstract

Laboratory experiments were conducted to assess the effects of some fungal isolates (supernatant and pellet) on germination of Striga seeds. Five fungal isolates were isolated from soil samples of Striga-infested or non infested sorghum fields in Sudan. Isolates differed in their effect on Striga seeds germination. Treatment with isolate Ai 41 resulted in seeds germination rates of 0.00 to 4.19% for pellet and culture filtrates, respectively. In comparison, seed germination rates were 44% and 51.96% for water and culture medium controls, respectively. The study further included investigation of the effect of isolate Ai 41 on germination of Striga seeds in the presence of two growth regulators, the auxin Indole-3-Butyric Acid (IBA) and the cytokinine Benzyle Amino Purine (BAP). High concentrations of IBA and BAP, reduced germination of Striga seeds conditioned in water significantly, in response to GR24 as compared to media control. The suppressive effects of isolate Ai 41 consistently increased with increasing both BAP and IBA concentration. In among all treatments, results indicated that IBA alone or in combination with fungal isolate Ai 41 completely inhibited Striga seed germination in response to GR24. This study indicates that some microorganisms could be employed as antagonistic to Striga. Their use as potential bioherbicides to control Striga appears promising.