Central Rice Research Institute Annual report...2011-12

line sesquioxide bound zinc were higher under aerobic
moisture regimes while the submergence helped to increase
the manganese oxide bound zinc, amorphous
sesquioxide bound zinc and residual zinc. The field
study with same treatments revealed that 7% reduction
in yield was observed under aerobic than the submergence
condition under no Zn applied conditions. However,
under Zn fertilized condition no significant yield
difference was observed. Averaged over the sources of
Zn application, the yield penalty of 8% was observed
under aerobic condition compared to flooded condition.
Microbial Resource Management and
Diversity Analysis
Microbial diversity of tropical soils
Characterization of PGPR microbes
The potent ACCdeaminase producing bacteria
viz.,Bacillus (n=2), Microbacterium, Arthrobacter, Microbacterium
and Paenibacillus spp. induced drought tolerance
in rice and increased seed germination by about
10% under anaerobic condition. Cellular protein and
RAPD analysis profiles of 20 Bacillus (B) and 23
Pseudomonas (Ps) strains produced 22-41 and 30-61 protein
fractions, and 2-4 and 2-6 amplicons, respectively
which ascertained molecular diversity of the PGPR
microbes (n=680). Further more, the Bacillus spp. were
more effective than the Pseudomonas spp. Among the
PGPRs, 40 were osmotolerant (7-18% NaCl), 110 were
HCN producer and 87 had biocontrol properties. Only
2 Bt isolates fixed nitrogen and 3 produced IAA,
whereas, 14 potent Bt strains solubilized P and cellulose,
and produced NH 3
.
Microbial activity under different rice based
cropping system
In soil, microbial diversity in terms of fluorescein
diacetate hydrolase (FDH), dehydrogenase (DH), β-glucosidase
(GS), and urease, alkaline (ALP) and acid phosphatases
(ACP) activities was more in rice-sesamumrice
rotation compared to rice-groundnut-rice, green
gram-rice-maize and cowpea-rice-maize cropping systems.
However, DH (125.06 g g -1 h -1 ), GS (102.12 g g -1
h -1 ) and FDH (8.41 g g -1 h -1 ) activities were maximum
in rice-groundnut and minimum in rice-cowpea crop;
Urease (71.12 mg g -1 h -1 ), ACP (67.53 g g -1 h -1 ) and ALP
(98.22 g g -1 h -1 ) were maximum in rice-sesamum and
minimum in rice-greengram cropping systems.
In another study, effect of different treatments viz.
FYM (5 t ha -1 ) with Sesbania aculeata, urea (60 kg N ha -1 ),
rice straw (5 t ha -1 ) with urea (60 kg N ha -1 ) (RSU), FYM
(5 t ha -1 ) with Sesbania aculeata (FYMS), FYM with Azolla
(5 t ha -1 ) (FYMA), rice straw with Sesbania aculeata (RSS)
on soil enzymatic activities was evaluated. The treatment
RSU resulted higher DH (135.86 g g -1 h -1 at panicle
initiation (PI) stage), GS (135.86 g g -1 h -1 at PI) and urease
(84.01 mg g -1 h -1 at maximum tillering (MT) stage)
activities followed by FYM Sand only urea; while FDH
(11.70 g g -1 h -1 at MT), ALP (108.72 g g -1 h -1 at PI) and
ACP (87.35 g g -1 h -1 at PI) were more in FYMS treatment.
Characterization of pesticide degrading bacteria
Nine chlorpyrifos degrading bacteria were identified
as Achromobacter xylosoxidans sub sp. xylosoxidans,
Xanthobacter flavus, Stenotrophomonas maltophilia,
Inquilinus limosus, Bacillus sp. and Sphingobium fuliginis.
After Phenotyping and phylotyping Methylobacterium
sp was identified as α, β, γ and δ-HCH degrader, which
degraded β-HCH from onset of growth and optimum at
stationary phase. β-HCH degradation was a novel
record.
Diversity analysis of entomopathogenic microorganisms
in rice ecosystem
Seventeen B. thuringiensis and 59 Pseudomonas
strains isolated from different rice ecology produced
siderophore, HCN and salicylic acid, effective against
insect pests and plant pathogens. The Bt (n=12) isolates
tolerated 8-18% osmotic stress. The osmolytes like
amino acids rendered tolerance to 3 and proline to 11
isolates but the osmozymes SOD and catalase rendered
stress tolerance to all Bt isolates. The ectC and ectABC
osmotolerant genes were identified in the isolates.
Out of 49 Bt strains isolated, 4 strains had the LC 50
values as 3.16x10 6 - 1.25x10 9 spore-crystals ml -1 against
LF in the field grown with rice cv. Sarala, Lalat, Naveen
and Swarna. The commercial strains i.e. TB70 of
bactospeine and TB73 of biolep were less effective than
the indigenous strains. Four potent native
entomopathogenic Bt against LF were formulated for
mass field application.
Five cry genesamplified by CJI1/CJI2, CJ4/CJ5, V(-)/
V(+), gral-nem(d)/gral-nem(r), gral-cyt(d)/gral-cyt(r)
amplimers, effective against the lepidopteran and coleopteran
pests of rice were identified from 67 out of
321 Bt isolates.
Improving Nutrient Use Efficiency of
Upland Rice through Native Beneficial
Soil Microorganisms
Integration of Arbuscular Mycorrhiza (AM)-
based bio-fertilizer with rice based cropping
systems
The AM-supportive crop management components
viz., (i) crop rotations (ii) application of AM inoculum
64 CRRI ANNUAL REPORT 2011-12