Abstract
A series of different field experiments were conducted at ICRISAT to assess the practical utility of a strain of Rhizobium, NC 92, as an inoculant for peanut, Arachis hypogaea L. Experiments were conducted in soil where substantial native Rhizobium populations exist (102 −104 cells/g dry soil), and ELISA (enzyme-linked immunosorbent assay) was used to identify NC 92 nodules. The results indicate that inoculation with strain NC 92 (a) results in 25-40% of the total nodules formed (b) mixing with other strains reduces the percent success of the inoculated strain in some experiments (c) whenever fungicides are used for seed treatment, direct application of rhizobia to the soil as liquid (by mixing the peat containing Rhizobium with water and pouring the resulting mixture into the furrow just before sowing) results in the formation of more nodules by the inoculated strain than the conventional seed inoculation method (d) very few NC 92 nodules are formed when the rate of inoculum is 104 cells/seed or less (e) the inoculated strain, NC 92 is able to survive in the soil for the following season.
Author notes
1Submitted as Journal Article No. 445, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru P. O. Andhra Pradesh 502 324, India.