Nitrogen Fertilization in Relation to Parasitism of Striga hermonthica on Sorghum vulgare PDF

Keywords

Striga hermonthica, nitrogen fertilizers, roots

Abstract

The effects of nitrogen fertilizers on the growth of Sorghum vulgare (Pers) and Striga hermonthica (Benth) were investigated in relation to parasitism. Addition of nitrogen fertilizers resulted in an increase in the growth of both infected and non-infected Sorghum plants. Application of either complete nutrient solutions or ammonium sulphate solutions to plants with split-root systems resulted in an increase in the growth of the root system which received high concentrations of the fertilizers compared to the other half or the root system which received only water. The shoot weights of the plants increased whether the fertilizer solution was added to one half of the root system or shared between the two halves, and also with or without infection. The number of Striga plants that emerged per pot was substantially reduced with increase of fertilizer especially by early application. Measurements of the plant growth promoting substances as "gibberellic acid or kinetin equivalents" in the xylem exudates of Sorghum vulgare revealed an increase in the concentration of both growth substances whether the plant was infected or non-infected with Striga hermonthica. These findings together with the more vigorous growth of Sorghum plants and the suppression of the growth of the Striga plants with the addition of nitrogen fertilizers are discussed and the usefulness of nitrogen fertilizers for control of Striga hermonthica parasitism confirmed