Mycorrhizal Development and Phosphorus Concentration in selected Kenyan Sorghum Cultivars

Abstract

Mycorrhizal associations are beneficial to plants and crop production because they enhance nutrient uptake especially phosphorus and micronutrients, such as zinc and copper. They also stimulate growth substances and may reduce stresses, diseases or pest attack. This study was carried out on sorghum genotypes that exhibited significant difference in growth and production on P-deficient soils. The objective was to find out if the genotypes developed different levels of mycorrhizal associations and tissue phosphorus. Results showed that plants in unfertilized soils developed extensive mycorrhizae than those in fertilized soils, no significant differences was observed in the extent of mycorrhizal development among cultivars grown in P-fertilized soils. The cultivars in unfertilized soils responded differently to mycorrhizal colonization, those with high level of mycorrhizal development increased growth compared to those that had low levels of mycorrhizal development in the unfertilized soils. The cultivars also responded differently to phosphorus concentration in their tissues. Phosphorus fertilizer apparently increased number of leaves and sorghum plant height. There was no relationship between phosphorus concentration in soil and level of mycorrhizal development though fertilizer significantly suppressed the level of mycorrhizal development in the plants.