Improving the capacity of beans for nitrogen fixation through varietal improvements and modifications of inoculum procedures.
April 06, 2006
Principal Investigator/s Peter Graham, Professor, Dept. Of Soil, Water, and Climate, University of Minnesota, St Paul
* Improving the capacity of beans for nitrogen fixation through varietal selection.
* Improving inoculant procedures used with beans
Benefits to North Dakota and Minnesota Dry Bean Growers
* Environmentally friendly and highly sustainable
* Reduce the costs of production through efficient N utilization
Back cross populations made to combine ability for enhanced nitrogen fixation and agronomically acceptable grain type were grown out at Becker, MN and Park Rapids, MN. Plants received no fertilizer nitrogen, but were inoculated with Rhizobium and dependent on nitrogen fixation for yield.
b) Fungicide treated or non-treated Montcalm bean seed was inoculated using a number of different liquid inoculant formulations, then stored for up to 30 days, with periodic evaluation of rhizobial survival on seed.
Individual plant selection has been practiced and seeds harvested, with further plant testing to be carried out in the greenhouse (Feb to May, 2006) and field (Summer, 2006). To this point no inoculant formulation tested has allowed survival of bean rhizobia equivalent to that obtainable with soybean rhizobia, and none has completely protected the rhizobia against seed applied fungicides. However:
*Much better survival of bean rhizobia was obtained using modified dilution fluid medium with PVP40 as the medium, than with other formulations
*UMR1899 generally survived better on the seed than did UMR1597
With the modified dilution fluid with PVP40 and strain UMR1899, rhizobial populations of 103 rhizobia seed-1 were recovered up to 15 days after inoculation where the seed was not treated with fungicide, but only up to 8 days where the seed was treated with Apronmax.