Studies on the endomycorrhizal synthesis in Seasamum indicum L

Abstract

The field study on AM fungal association in sesame newlineconducted during the first phase of the present newlineinvestigation revealed the existence of wide variation in root newlinecolonization and spore density in the rhizosphere soils. newlineSoil characters had a profound influence on both root newlinecolonization and spore density in soil. G. dimorphicum was newlinethe most dominant species associated with sesame grown newlinein the region under study. newlineThe developmental pattern of fungal structures newlinediffered with AM species infecting sesame. Among the newlinedifferent AM fungi more fungal structures such as newlineintercellular hyphae vesicles and arbuscules were newlineproduced by plants inoculated with G. versiformae. newlineDevelopment of fungal structures was more vigorous newlineduring early stages of plant growth. newlineThe indigenous isolates of AM fungi improved the newlinegrowth and yield characters of sesame. Among the newlinedifferent indigenous AM fungi, G. dimorphicum was the newlinemost efficient one in enhancing the growth and yield of newlinesesame. newlineInfectivity of spores of G. dimorphicum on sesame newlinevaried after incubation in different soil types. Addition of P newlineto soil negatively affected the infectivity of AM fungi. The newlinespores of G. dimorphicum retained its infectivity upto five newlinemonths in most soils in the absence of host. newlineScreening of field grown sesame accessions revealed newlinethat genotype dependent variation exists in sesame. newlineSesame accessions in general recorded a very low level of newlineAM colonization in roots. However, the crop was greatly newlinedependent on indigenous AM colonization for growth and newlinenutrition. newlineGrowth yield, biochemical components and P newlinenutrition were improved by AM inoculation at the minimal newlineuse of P fertilizers and irrigation. The combined effect of newlineAM fungi, P fertilizer and irrigation helped the plant in newlineenhancing the above parameters. newlineThe tripartite interaction involving AM fungi, newlineAzospirillum and sesame at the moderate level of NP newlinefertilizers led to an increase in AM colonization, growth and newlinenutrient status of the crop.