Studies on the response of mulberry (Morus sp.) to phosphate solubilizing microorganism



Project Code






Studies on the response of mulberry (Morussp.) to phosphate solubilizing microorganism.




Nagendra Kumar TD,Sukumar J,


Project period


1993 – 1998


Institute/ University


Karnataka State Sericulture Research and Development Institute, Bangalore, Karnataka


Project cost





  • To isolate phosphate solubilizng fungi and bacteria from the rhizosphere soils of mulberry and farmyard manure.
  • To screen the efficiency of isolated microorganisms to solubilize tricalcium phosphate and rock phosphate in Pikovskaya’s broth and on hydroxyapatite agar medium.
  • To screen the response of mulberry to selected PSMs with two P source viz., super phosphate and rock phosphate.
  • To study the feasibility of utilizing rock phosphate in place of super phosphate or substitute a part of it through rock phosphate.
  • To study the rearing performance of silkworm fed on leaves from PSM inoculated plants.
  • To study the response of mulberry to dual inoculation with PSM isolates and PSM-vesicular arbuscular mycorrhizal (VAM) combination
  • To study the effect of PSMs on the survival, growth and root proliferation of mulberry saplings.


Important findings

One fungus and 9 bacteria were obtained from mulberry rhizosphere and 4 fungi and 5 bacteria were isolated from farmyard manure. Majority of the fungi isolated belonged to the genus Aspergillus while all the bacterial isolates were gram negative rods except one isolates which was gram negative coccoid.

The overall comparison of inoculated treatments receiving different P sources showed that except Trichodermasp., all others  significant influenced on growth, biomass production and P2O5 uptake by mulberry.

Fungal isolates viz.,Aspergillus awamori,,A.niger and one bacteria were selectedalong with the two reference organisms A. awamoriandB. megateriumvar. phosphaticum. Inoculants in presence of SSP + MRP were superior over the inoculated treatments receiving MRP.

In presence of SSP + MRP, A. awamorirecorded 11.34 and 14.29 percent increase in leaf yield at 25 and 50 kg inoculum/ha respectively over the uninoculated control (SSP) followed by the ref. fungus A. awamori(11.19 and 13.86), A. niger(F-14) (10.92 and 13.87%),B. megaterium(10.50 and 13.03%) and B-1 (9.66 and 13.45%).

The bacterial isolates B-1 and B. megateriumvar. phophaticum in combination with Glomus mossaeshowed highly significant increase in the growth parameters of mulberry compared to the plants received the individual inoculations of PS fungal isolate and their combination with Glomus mossae.

The encouraging results obtained with A. niger(F-14) and A. awamori(F-10) combination in presence of MRP and SSP + MRP as P sources, suggested that there is a scope to explore further combinations of PSMs to strike at more number of suitable combinations with greater benefits on growth parameters of mulberry.

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