Effect of seed inoculation with Bacillus subtilis and Streptomyces griseus on the growth of cereals and carrots

Abstract

The effect of Bacillus subtilis A13 and Streptomyces griseus 2-A24 on the yield of cereals and carrots was studied. The organisms, both antagonistic to Rhizoctonia solani, were applied individually to barley, oats and wheat for sowing at three sites with a known incidence of R. solani. Root disease was not effectively controlled, yet the seed treatments increased grain yield and dry matter production at one site, advanced time of heading at another site and increased tiller number at two sites. Evidence was obtained that the organisms persisted on pericarps in soil for 5 weeks after sowing. In subsequent trials application of B. subtilis and S. griseus in combination with a pellet treatment increased marketable yields of carrots by 48% and 15% respectively over controls. Addition of the organisms to seed without pelleting increased yields by 17% over controls. These results indicate a non-specific effect of B. subtilis and S. griseus, since they increased growth of plants belonging to two different families, the Gramineae and Umbelliferae, in different soils.

Actinomycetes, promising tools to control plant diseases and to promote plant growth

“…Marketable yields were increased over controls by 17% and 15% in two separate field trials. Specifically, both trials also indicated an increased yield of large and very large grade carrots over controls (Merriman et al 1974). Nearly 20 yr later, El-Abyad et al (1993) described the use of three Streptomyces spp.…”

“…for the improvement in tomato growth, although this was not formally tested (El-Abyad et ai 1993). While thèse studies by El-Abyad et al (1993) and Merriman et al (1974) reported plant growth enhancement as a function of inoculation with Streptomyces, neither they investigated the inoculum under gnotobiotic conditions, nor the possible mechanisms of streptomycete-mediated growth promotion.…”

“…This is surprising as streptomycetes, generally accounting for an abundant percentage of the soil microflora, are particularly effective colonizers of plant root Systems and are able to endure unfavorable growth conditions by forming spores (Alexander 1977). While the bénéficiai effect of some strains of PGPR on particular crops is certain, the mechanisms em-5 ployed by PGPR are unclear (Glick 1995 Merriman et al (1974) reported the use of a Streptomyces griseus (Krainsky) Waksman and Henrici isolate as a seed treatment of barley, oat, wheat and carrot, in order to increase their growth. The isolate was originally selected for the biological control of Rhizoctonia solani.…”

“…It is proposed that the production of antibiotics increases an organism aptitude for survival in the former case by acting as an alternative (chemical) défense mechanism (Maplestone et al 1992). Several studies hâve reported antagonism between actinomycetes and a diversity of phytopathogens such as Altemaria, Fusarium, Macrophomina, Phytophthora, Pythium, Rhizoctonia, Verticillium (Chattopadhyay and Nandi 1982;Heisey and Putnam 1986;Hussain et al 1990;Iwasa et al 1970;Merriman et al 1974;Gottlieb 1981, 1984;Sabaou and Bounaga 1987;Trejo-Estrada et al 1998;Valois et al 1996;Wadi and Easton 1985).…”

Biocontrol and growth promotive potential of <i>Streptomyces</i> spp. in black pepper (<i>Piper nigrum</i> L.)

“…For eg. as early as 1974, Merriman et al reported the use of a strain of Streptomyces griseus, which was originally selected for the biological control of Rhizoctonia solani, as a seed treatment for barley, oat, wheat and carrot, in order to increase their growth (Merriman et al, 1974). Similarly El-Abyad et al, (1993) described the use of three Streptomyces sp.…”