Abstract

Take-all caused by the soil-born fungi Gaeumannomyces graminis (Sacc) Arx & Olivier is an important crown and root rot diseases of wheat throughout the world. Biological control and plant nutrition management are two effective methods for the control of this disease. In this study, effect of plant nutrition was investigated on improvement of wheat growth and suppression of the Take-all disease. For this purpose, the effect of iron sulfate, copper sulfate and zinc sulfate on Take-all disease of wheat was studies on the basis of infected roots and production of shoot dry weight. The obtained results revealed that the experimental soil was slightly alkaline. The soil contained adequate amounts of nitrogen and zinc, but was poor in availability of iron, cupper and mild deficit in phosphorus. In order to investigate the effect of the nutrients on growth and severity of the disease, four levels (0, 2.5, 5.0 and 10 mg/kg soil) of micronutrients were used. Iron had greatest effect on suppression of Take-all disease among applied micronutrients. The infected roots decreased from 89 to 53% and abolished symptoms on wheat crown up to nine times with the application if iron. In addition, iron increased the dry weight of aerial parts of wheat from 0.78 to 1.3 g per plant. The effects of zinc and copper fertilizers on disease suppression on wheat was less than that of iron with decreased infected roots to 57 and 64%, respectively. Overall, increase in the amount of iron sulfate decreased the severity of the disease and enhanced biomass of aerial parts in infected wheat plants.