Arbuscular Mycorrhizal Incidence and Infectivity of Crops in North West Frontier Province of Pakistan

Spores density and mycorrhizal colonization were studied in twenty-five rhizosphere samples of some selected soils and plant roots from fertile and marginal soils of North West Frontier Province of Pakistan. All tested plants are considered to be mycorrhizal plants. Highest number of mycorrhizal spores was found in Potatoes, Barley, rice and chickpea (>4000 spores kgG soil) in fertile soils. Fields of alfalfa, wheat, barley, oat 1 and grasses gave the highest number of spores in marginal soil. The root infection levels varied in different crops from one site to another. Barley, Potatoes and oats showed the highest infection rates being 44, 40 and 33%, respectively in fertile well managed soil, whereas 52, 50 and 43% highest mycorrhizal infections rates were observed in barley, alfalfa and wheat, respectively in marginal soil. Generally, spores density in soil samples seemed to be dominated by the species of Glomus fasciculatum. However, spores of Glomus intraradices and Glomus mosseae were also identified in the samples. Soils under investigation have pH value ranged from 5.6 to 8.5 with low concentration of available phosphorus and high contents of total phosphorus. Results suggest that (V)A mycorrhizal fungal spores and root colonization varied in different crops from one site to another under different agro-ecological conditions.