Response of alfalfa to inoculation with Sinorhizobium meliloti strains indigenous to Saudi Arabian soils.

摘要

For evaluation the efficacy of nineteen Sinorhizobium meliloti strains from different fields sites in Saudi Arabia to screen the highly effective strains on the nodulation and productivity of alfalfa cultivar CAF 101 this study was conducted under the green house and open field. The symbiotic relationships and competitive ability were studied in the field. A randomized complete block design with three replicates was used. The results showed that all strain inoculation treatments produced significantly higher dry biomass and nitrogen content per alfalfa plant than that corresponding of uninoculated one. The four indigenous Sinorhizobium meliloti strains (KSU 73, KSU 176, KSU 188 and KSU 121) were the most effective strains, as evidenced by increase in dry weights either in green house or in the field conditions. The field experiment showed that the inoculation of alfalfa with four effective strains of alfalfa rhizobia resulted in increases of 3.6-12.1% in the dry matter production and 6.8-27.6% of crude protein. Sinorhizobium meliloti strain KSU 73 was the most effective inoculant under the greenhouse and field condition. The fluorescent antibody technique showed that the strain KSU73 had high competitiveness in the field. It occupied 64% of nodules in alfalfa after 10 weeks of growth. In conclusion, a simple technique to select highly effective and competitive symbiotic strains specific to alfalfa was established.