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QUANTIFICATION OF PHYSIOLOGICAL LOSSES DUE TO CORN LEAF APHID, Rhopalosiphum maidis (Fitch) IN SORGHUM (Sorghum bicolor (L.) Moench)”

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Title QUANTIFICATION OF PHYSIOLOGICAL LOSSES DUE TO CORN LEAF APHID, Rhopalosiphum maidis (Fitch) IN SORGHUM (Sorghum bicolor (L.) Moench)”
 
Creator ANJALI, M S
 
Contributor SRIDEVI, D
 
Subject planting, diseases, genetics, genes, biological phenomena, polymorphism, segregation, genotypes, sowing, rapd
 
Description The present studies were conducted in the Entomology laboratory and green
house, CRIDA, Santhoshnagar, Hyderabad with an objective to study the biology of
aphid, to establish relationship between insect density and leaf pigments and estimate the
relative water content (RWC) in sorghum due to feeding by corn leaf aphid,
Rhopalosiphum maidis (Fitch).
R. maidis on sorghum had a life cycle of 7.79±0.12 days, adult longevity of
12.27±0.27 days, life span of 16.25±0.80 days, fecundity and rate of reproduction 35.97
progenies/female, 9.15 progenies/female/day, net reproduction rate (R0) 45.05, mean
generation time (Tc) 9.24, intrinsic rate of natural increase (rm) 0.44, innate capacity of
increase (rc) 0.41 and corrected mean generation time T 8.73 days, respectively. The
length and width of different stages of R. maidis were: 720.57± 9.95 μm and 303.62 ±
5.59 μm (1st instar); 978.46 ± 13.51 μm and 412.83 ± 5.53 μm (2nd instar); 1399.52 ±
24.56 μm and 581.74 ± 12.33 μm (3rd instar); 1737.5 ± 20.28 μm and 733.98 ± 10.96
μm (4th instar) and 1833.63 ± 15.89 μm in length and 783.26 ± 10.82 μm (adult),
respectively.
The reduction in chlorophyll content, fluorescence and photosynthetic rate ranged
between 9.06 to 29.79%; 1.35 to 6.75 (Fv/Fm) and 6.15 to 32.30 μmol CO2 m-2 sec-1 respectively,
at different levels of infestation, all the three physiological parametes being significantly low at
high infestation (300 aphids/plant) compared to no, low (100 aphids/plant) and medium
infestation (200 aphids/plant).
A negative correlation between aphid density and physiological parameters indicated that
an increase in the incidence of R. maidis (density) decreased the chlorophyll content,
fluorescence and photosynthetic rate from 20 days after realease of a mixture of aphid population.
A significant reduction in all the three physiological parameters were recorded at high density
level of aphids on sorghum.
The quantification of leaf pigments viz., chl a, chl b, chl (a+b), carotenoid and flavonoid
indicated a significant loss in chl (a+b) and carotenoid in medium and high infestation compared
to control. The per cent reduction of these pigments ranged between 17.07 to 39.02 and 10 to 40,
respectively at different levels of infestation. However, loss of chl a and chl b was more
significant in medium infestation compared to low and high infestation. On the contrary, the
flavonoid content increased significantly in medium and high infestation.
The RWC ranged between 89.3±1.20 to 87.2±1.21%, the per cent of reduction varying
between 5.03 to 2.31 at different levels of infestation. The pigment loss was greater at high
densities than the water loss.
 
Date 2017-01-03T10:43:34Z
2017-01-03T10:43:34Z
2016
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/94084
 
Language en
 
Relation D10028;
 
Format application/pdf
 
Publisher PROFESSOR JAYASHANKAR TELANGANA STATE AGRICULTURAL UNIVERSITY. HYDERABAD