RESPONSES OF SOME PROMISCUOUS AND NONPROMISCUOUS SOYBEAN CULTIVARS TO INOCULATION AND PHOSPHORUS APPLICATION

ABSTRACT

Pot and field studies were carried out at the University of Ghana, Legon, to evaluate

the effect of Bradyrhizobium japonicum inoculation and five rates of phosphorus

application on growth, nodulation and dry matter production of some promiscuous

and non-promiscuous soybean cultivars in pots and finally the effect of three rates of

phosphorus and inoculation on growth, nodulation, dry matter production and yield

of a promiscuous cultivar "Bengbie" in the field.

In the pot experiment, one non-promiscuous cultivar (Davis) and two promiscuous

cultivars (Bengbie and Anidaso) were inoculated with B. japonicum strain TAL 102

and also received 0, 8.9, 17.9, 26.8 and 35.7mg P/kg soil (equivalent to 0, 20, 40, 60

and 80kg P/ha.). Inoculation generally caused significant increases in nodulation,

shoot diy weight, shoot nitrogen (N) and shoot (P), but not root dry weight.

Phosphorus application on the average increased nodulation, root and shoot dry

weight and shoot N and P.

The non-promiscuous cultivar produced higher nodulation and shoot N than the

promiscuous cultivars on inoculation.

Interaction between inoculation and cultivar was significant for nodulation, root dry

weight and shoot N while phosphorus and cultivar interaction was significant for

shoot dry weight and shoot P.

In the field experiment, one promiscuous cultivar "Bengbie" was inoculated with B.

japonicum strain TAL 102 and given 0, 30 and 60 kg P/ha. Inoculation in the field

increased nodulation, root dry weight, shoot N and shoot P. This indicates that

promiscuous cultivars can benefit from inoculation. However, inoculation failed to

increase pod number and final grain yield.

Phosphorus application up to 60kg/ha did not significantly increase nodulation,

shoot and root dry weight, shoot N and P, 100 - seed weight and final grain yield.