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EFFECT OF ELEVATED CARBON DIOXIDE (eCO2) ON BACTERIAL LEAF BLIGHT (BLB) OF RICE

KrishiKosh

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Title EFFECT OF ELEVATED CARBON DIOXIDE (eCO2) ON BACTERIAL LEAF BLIGHT (BLB) OF RICE
 
Creator Kar Mohapatra, Ruchismita
 
Contributor Pasupalak, S.N.
 
Subject EFFECT, ELEVATED CARBON DIOXIDE, BACTERIAL LEAF BLIGHT, RICE
 
Description Rice is the most important cereal crop in India including the state of Odisha. However, the rice productivity in the state is quite low. Pest and disease incidence is one of the major causes of such low rice yield. Bacterial Leaf Blight (BLB) is one of the most devastating rice diseases. Its epidemic development is favoured by high temperatures. Elevated CO2 is a major greenhouse gas to contribute global temperature rise. Change in seasonal weather due to eCO2 induced climate change is considered significant on production and distribution of BLB. Further, eCO2 is likely to change microclimate of rice crop and thereby modifying plant–pathogen interaction. Application of nitrogen fertilizer also claimed to affect host-pathogen relationship. Very few studies have been made on the effect of eCO2 on BLB of rice as influenced by soil N supply. Hence, a pot experiment was conducted in Open Top Chambers (OTCs) at Central Research Station, O.U.A.T., Bhubaneswar in kharif 2012 to find out the effect of eCO2 (476 ppm) on incidence of BLB and infectivity and morphological properties of its causal organism (Xanthomonas oryzae pv. oryzae) as influenced by different N levels.
Rice plants were grown in open field, ambient CO2 OTC and eCO2 (476 ppm) OTC and were artificially inoculated with Xanthomonas oryzae pv. oryzae (X.o.o.) at panicle initiation stage. CO2 incubator studies were also made for inoculum characteristics.
Net photosynthesis rate (Pn) declined and respiration rate increased generally after the inoculation at 20 and 30 days after inoculation (DAI). Pn was more in the open field (32.1 μmol m-2 s-1) than in ambient OTC (19.2 μmol m-2 s-1) at 10 DAI. However, reverse was the case at the later stage (30 DAI). Elevated CO2 maintained lower Pn and higher respiration rate in BLB infected plants at later stages. At 20 DAI, eCO2 OTC maintained more respiration rate (2.4 μmol m-2 s-1) than ambient CO2 OTC (2.1 μmol m-2 s-1). Leaf nitrogen content was less in eCO2 in both inoculated and un-inoculated plants (0.6% and 1.2%) than in open field (0.9% and 1.4%).
Plants grown in open field had more blighted leaf area (41.4%) at 10 (DAI) than those in eCO2 OTC. Elevated CO2 reduced colony size in 15th generation of X.o.o. (232.4 μm dia) compared to ambient CO2 (347.3 μm dia). The cell length varied slightly in CO2 incubator up to 20th generation. The biochemical characters of X.o.o. and sugar utilization by the bacterium did not differ between ambient and elevated CO2 condition. However, dextrose utilization was comparatively slower under eCO2 than that in ambient CO2 condition. All the antibiotics except penicillin showed inhibitory effect on the growth of X.o.o. under both the conditions.
Recommended N resulted in larger blighted leaf area (45.9%) than no N addition (29.4%) at 30 DAI. Such increased blighted area was mainly due to longer lesion both at 20 and 30 DAI (15.4 cm and 14.5 cm) than no N addition (9.2 cm and 8.5 cm). Pn was more (28.7 μmol m-2 s-1) with recommended N than with only straw addition (21.3 μmol m-2 s-1) at 10 DAI. However, N did not affect respiration rate. In Inoculated plants, leaf N content was more (0.9%) with no N addition than with higher N (125% recommended). However, in un-inoculated plants, it was more (2%) with only straw addition than with no N addition (0.8%). The interaction effect between nitrogen and environment for the blighted leaf area was absent.
 
Date 2017-01-04T11:32:30Z
2017-01-04T11:32:30Z
2013
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/94342
 
Language en
 
Relation Th;4029
 
Format application/pdf