Studies on performance of different rhizobium strainsn in summer groundnut

摘要

Groundnut is the major oilseed crop accounting for 45 per cent of total oilseed area and 55 per cent of the total oilseed production of the country. With ever increasing cost of nitrogenous fertilizers greater emphasis has been laid on the use of alternative and renewable sources of nitrogen. Biological nitrogen fixation through micro-organisms as bio-fertilizer comes to the rescue of the farmer as a cheap and supplementary sources of nitrogen. One of the major components limiting pod yield of groundnut is ineffective nitrogen fixation. To ensure effective nodulation, the crop has to be provided with highly efficient rhizobium strains in the vicinity of its root system (Anon., 1987). The ability of an introduced rhizobial strain to out compete thenative strains in soil is perhaps a foremost consideration in selecting a suitable strain (Date, 1976). Beneficial effect of rhizobial inoculation on groundnut yield and net returns is well established (Joshi et ai, 1989 ; Prabhakaran and Sivasubramanian, 1991). Kalaiselven et al. (2000) and Thakare and Rasal (2000) also reported significant response of groundnut to different strains of rhizobium. Hence, the present investigation was undertaken to identify the most efficient strains of rhizobium for summer groundnut in the Eastern Dry Zone of Karnataka.