Effect of Some Seed Borne Fungi on Seed Germination and Seedling Emergence of Soybean and Antifungal Impact of Certain Botanicals

Abstract

An investigation was carried out to examine the effect of some seed borne fungi on seed germination and seedling emergence of soybean. A total of five fungi species comprising four genera namely <i>Aspergillus flavus</i>, <i>Aspergillus niger</i>, <i>Fusarium oxysporum</i>. <i>Penicillium chrysogenum</i> and <i>Colletotrichum sp</i> were isolated from the tested seeds. The effects of the mycelial suspension of the isolated fungi on percentage seed germination and seedling emergence was studied. Ten seeds were soaked in mycelial suspension of each fungus for 1hour before placing on Petri-dishes and sowing in bags containing 3 kg sterilized soil in triplicates. It was observed from the study that <i>Penicillium chrysogenum</i> had the highest inhibitory effect on seed germination while <i>Aspergillus niger</i> had no effect on seed germination. Also, the result showed that all the isolated fungi had a significant effect (p<0.05) on length of radicle with <i>A. flavus</i> recording the least length of radicle (2.10 cm) as compared with the control (4.75 cm). <i>Fusarium oxysporum</i>, <i>Penicillium chrysogenum</i> and <i>A. flavus</i> significantly reduced shoot length. While all the isolated fungi had significant differences at p<0.05 on root length with <i>P. chrysogenum</i> recording the least root length (5.15 cm) as compared with 10.13 cm observed on the control. The efficacy of both the aqueous and methanol extracts of <i>Aframomum melegueta</i> and <i>Petiveria alliacea</i> was assessed against the mycelial growth of the isolated fungi at 10, 20 and 30% concentration. The methanol extract of both plants most especially that of <i>Aframomum melegueta</i> performed better in inhibiting the radial growth of <i>Aspergillus flavus</i>, <i>Aspergillus niger</i>, Fusarium oxysporum and <i>Colletotrichum sp</i>.