|Budget Amount *help
¥3,200,000 (Direct Cost : ¥3,200,000)
Fiscal Year 1994 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1993 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1992 : ¥1,600,000 (Direct Cost : ¥1,600,000)
In order to improve the nodule occupancy of inoculant rhizobia and to increase nitrogen fixation, utility of preferential ability of soybean cultivars harboring nodulation restricting genes (Rj) for rhizobial strains was examined.
The Rj2Rj4-genotypes of soybeans were isolated from of progenies of the cross of soybean IAC-2 (Rj2Rj3) and Hill (Rj4) and were demonstrated to be Rj2Rj3Rj4-genotypes, therefore, Rj3 was considered to locate in the same chromosome as Rj2. Nodule bacteria were isolated from Rj2Rj3Rj4-soybeans in field were classified into 2 categories, one of them produced IAA and alkalized the culture medium and the other did not produce IAA and alkalized the medium but had acidified it ce 2 weeks. Then, the isolates were separated into 9 types based on their features of colonies and examined the relation between the types and Rj-genotypes of the soybeans, from which the rhizobia were isolated, however, the correlation did not recognized. In pot and field experiments, the Rj2Rj4-genotypes of soybean were showed to prefer more actively USDA110 serotype of rhizobia, which included Hup positive strains at high rates more than the other genotypes.
The restriction fragment length polymorphism (RFLP) of isolates from various Rj-genotypes grown in fields was examined, however, the correlation between RFLPs and the genotypes of soybean, from which rhizobia were isolated, could not be found. But some groups of soybean classified by nodulation-type or physiological features were showed to have the characteristic bands of P.These results indicated that the structure analysis of the B.japonicum gemome was useful for clarification of the physiological mechanism of preferences of soybean harboring Rj-genes for rhizobial strains.