MSc

Management of damping off, the most destructive disease of chilli both
111 nursery and main field incited by Pythium aphanidermatum (Edson) Fitz.
using native AMF was attempted in the present investigation. Out of nine
native AMF and one identified culture (Glomus mosseae) screened, the
cultures Ms and M9 were found effective for suppression of damping off and
growth improvement in chilli.
Application of AMF inoculum in the nursery furrows along with chilli
seeds was very effective for rapid and easy colonization of AMF. Likewise
application of AMF inoculum at the rate of 850 g m-2 was selected as the
economic dose for achieving satisfactory colonization of AMF.
Azospirillum spp. were isolated from chilli roots collected from
different locations of Thiruvananthapuram district. The in vitro nitrogen
fixing capacity of the isolates ranged between 11.2 and 20 mg N s' of malate
and IAA production between 21 and 55 ug mrl. Six best isolates which
performed well under in vitro screening were selected an-d subjected to in vivo
screening for growth, biomass production and yield in chilli. The isolates
Az-l and Az-2 which performed well both under in vitro and in vivo
screening were selected for further studies. Based on the characterization
studies it was found that the isolate Az-l is related to Azospirillum lipoJerum
and Az-2 is similar to Azospirillum brasilense. The isolate Az-l grew well at
pH 5,6 and 7 whereas the isolate Az-2 grew well at pH 6 and 7.

In the study on the interaction of native AMF and Azospirillum on
damping off disease suppression, pre-inoculation of chilli seedlings with M9
culture alone recorded the least disease incidence. Eventhough dual
inoculation of AMF and Azospirillum could suppress the damping off,
Azospirillum had no direct effect on disease suppression. However dual
inoculation of AMF and Azospirillum (M9A2PO) significantly increased the
growth, biomass production and yield in chilli. The present study forms the
first report of the synergistic effect of AMF and Azospirillum for the
management of damping off and growth improvement in chilli.
The present investigation emphasizes the importance of pre-inoculation
of AMF in the chilli nursery as a prophylatic measure to prevent pathogen
attack. The technology of combined inoculation of AMF and Azospirillum
could be recommended for adoption by the vegetable farmers. Eventhough the
present study was carried out in chilli, the same cultures could be
recommended for all transplanted solanaceous vegetables after confirming the
results through field trials.