Effects of damping-off fungus on seed germination of amaranth (Amaranthus Hybridus)

Seed borne pathogens are microorganisms that can prevent seed germination and cause serious threats to seedling development in the field. The research was conducted on the effects of damping off fungus on seed germination of Amaranth (Amaranthus hybridus) collected from some Agricultural farmland in Lapai Local Government Area of Niger State, North central Nigeria. The isolation of fungal species from Amaranthus hybridus seeds of the infected plants having symptoms of damping off disease using agar plate method and was identified using the morphological characteristics features from mycological atlas. Isolation from the infected seeds revealed that Rhizoctonia solani were associated with the plants. Seed weight (mg) and seed germination (%) were determined using the international rules for seed testing and the physiological seed quality indices were determined; these are germination index (GI), germination rate index (GRI) and seedling vigor index were arranged in Randomized Complete Block Design (RCBD) all in triplicates. The result indicated that seeds from uninfected plants recorded seed weight (8.97mg) as compared with the infected seeds (5.21mg), there was significantly higher germination (98.67%) observed in uninfected seeds compared with seeds of Amaranthus plants that were infected (32.13%) with damping off fungus. Germination index was observed to be higher in seeds of uninfected plants (9.34) and lower in seeds of infected plants (4.34). The significant effects observed of the fungus on both seed and seedlings are highly virulence on the infected plants. The research revealed that a very good association between Rhizoctonia solani causing damping off disease and seed germination failure of Amaranthus hybridus plants. In the cultivation of Amaranthus hybridus, seed weight, and physiological seed quality attributes should be considered for an effective damping off disease suppression.