ISSN: 0041-3216 (Online), 0041-3216 (Print)
Volume 62 Number 2
Comparison of nodulation promiscuity of US- and Asian-type soya beans
The symbiotic responses of three Asian-type soya bean cultivars were compared with those of three US-type cultivars and of a cowpea cultivar. A total of 59 strains representing four different groups of rhizobia were used: (a) fast-growing Rhizobium japonicum, (b) slow-growing R. japonicum, (c) Rhizobium spp isolated from US- and Asian-type soya beans grown in West Africa, and (d) Rhizobium spp isolated from cowpeas grown in West Africa. The US-type cultivars were effectively nodulated by slow-growing R. japonicum, but with most of the other strains they produced either no nodules or ineffective nodules. The Asian-type soya beans each responded differently to the four groups of rhizobia, and although they produced effective nodules with a majority of the strains, the symbioses were ineffective with significant frequency. The patterns of effectiveness of the West African soya bean rhizobia with the Asian-type soya beans correlated strongly with the location of origin of the strains. The greatest degree of promiscuity and the highest frequency of effective nodulation were found with the cowpea.
Keywords: Glycine max; Rhizobium; Nodule; Effectiveness