ISSN: 2471-9315
Asma J Al Jaradi, Rhonda Janke, Sajeewa S Maharachchikumbura, Issa H Al-Mahmooli and Abdullah M Al-Sadi
Oman Botanic Garden, Oman
Sultan Qaboos University, Oman
Posters & Accepted Abstracts: Appli Micro Open Access
The aim of this study was to characterize fungal species associated with root diseases of Phaseolus vulgaris, Vigna unguiculata, Vigna radiata and Vicia faba in four geographical regions in Oman. A total of 91, 83, 12 and 51 root samples were collected from P. vulgaris, V. unguiculata, V. radiata and Vicia faba, respectively. The samples were collected from plants suffering from weakened growth and yellowing symptoms. Isolations on 2.5% potato dextrose agar yielded 204 fungal isolates belonging to at least six different genera, with most of the isolates belonging to Alternaria and Fusarium. Identification using sequences of the internal transcribed spacer region of the ribosomal RNA gene (ITS rRNA) revealed that the isolates belong to 20 fungal species, the most dominant of which was Alternaria alternata. Pathogenicity tests were conducted on each plant species using two to three of the most common fungal isolates. The inoculations on P. vulgaris revealed that Pythium aphanidermatum induced rotting and damping-off symptoms, while Fusarium equiseti induced yellowing symptoms on the leaves. Rhizoctonia solani produced lesions and root rot on V. unguiculata while Curvularia lunata and Curvularia aeria produced root lesions on the roots of V. unguiculata and V. radiata, respectively. Alternaria alternata produced brown symptoms on the tap root of Vicia faba. P. aphanidermatum resulted in a significant reduction in the fresh weight, dry weight and shoot length of P. vulgaris. However, all other fungal species did not have any significant effect on the fresh weight, dry weight; shoot length or root length of any of the bean species or cowpea which was tested in this study. The study shows that, several fungal species can be found associated with the roots of beans and cowpea in Oman. Some of these fungal species can result in major effects, especially during the seedling stage. Other fungal species can have minor effects or are saprophytes on bean and cowpea roots. Future studies should address the effect of these fungi and others on mature plants and on yield.