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Interaction of acid exudates in chickpea with biological activity or cry toxins from Bacillus thuritgiensis berliner against Helicoverpa armigera (hubner)

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Title Interaction of acid exudates in chickpea with biological activity or cry toxins from Bacillus thuritgiensis berliner against Helicoverpa armigera (hubner)
 
Creator Surekha Devi, V
 
Subject Chickpea
Entomology
 
Description The H armigera egg and larval numbers before and after sprays of B. rhuringiensis
(Bt) formulation ~iole~w'e re low on the chickpea genotypes ICC 506 and ICCV 10 across
BI concentrations as compared to those on L 550 and C 235 during vegetative and flowering
stages. Leaf feeding and pod damage were lowest on ICC 506, followed by ICCV 10 across
Bt concentrations as compared to that on L 550 and C 235. During the 2005-06 post-rainy
season and first planting during the 2006-07 post-rainy season, highest grain yield was
recorded in case of ICCV 10. In the second planting, the genotypes ICCV I0 and ICC 506
recorded the highest total grain yield. There were no significant d~fferences between the
genotypes and Bt concentrations for grain yield.
Significantly lower leaf damage was recorded on ICC 506 across Br concentrations in
detached leaf assay under laboratory conditions. Larval survival and larval weights were
lower in ICC 506, ICCV 10. and C 235 across Br concentrations as compared to that of L
550. Survival and development of H. armigera on ICC 506, ICCV 10, and C 235 sprayed
with different concentrations of Bt differed significantly with that of the unsprayed plants of
these genotypes. At higher concentrations of Br (0.1.0.2. and 0.5%), there was no survival of
the armigera larvae. At lower concentrations of Br (0.05%), the larval survival and larval
and pupal weights were lower on the sprayed (0.05%) plants than those on the unsprayed
plants of different chickpea genotypes. Larval and pupal periods were prolonged on plants
sprayed with Bt. There was a significant reduction in fecundity of H armigera reared on
chickpea plants sprayed with Br.
At the vegetative and flowering stages, ICC 506 had the highest amounts of oxalic
acid on dry weight and leaf area basis. At the podding stage, ICCV 10 had the highest amount
of oxalic acid on dry weight basis. On dry weight basis, ICCV 10 had the highest amount of
malic acid at the vegetative, flowering, and podding stages. On leaf area basis, ICCV 10 had
the highest amount of malic acid at the vegetative stage, whereas C 235 had the highest
amount of malic acid at the flowering and pcdding stages. Fumaric and citric acids were
recorded at the podding stage only. The genotype C 235 had the highest amounts of fumaric
and citric acids. There was no citric acid in ICC 506.
The survival and development ofH armigera larvae reared on artificial diet with
leaflpod powder of different chickpea genotypes and Br were significantly lower as compared
to that on the standard artificial diet, and the diets without Br. Larval survival, larval and
pupal weight, and pupation and adult emergence were lower on the resistant genotypes than
on the susceptible ones, and the standard artificial diet. Oxalic and malic acids in the artificial
diet increased the biological activity of Br toxins on the H armigera, and resulted in reduced
larval weight, prolonged development, and reduced longevity and fecundity.
The food, midgut, and faecal matter samples of larvae fed on diet with different
amounts of organic acids and BI indicated the conversion of protoxin to toxin, and binding to
the brush border membrane vesicles (BBMV) of midaut. Due to the conversion of p rot ox in to
toxin and binding to the BBMV, the amount of Bl toxin in the midgut samples w& greater as
comaared to that in the food sam~lesT. here were no significant differences in the amounts of
Bt p;otein present in the midgutsamples of the larvae-fed on diet with different amounts of
oxalic and malic acids and BI toxin, indicating that the organic acids did not influence the
conversion of protoxin to toxin. The amounts of protein in the BBMV preparations ranged
from 0.131 to 0.326 mg c&". The amount of protein estimated from the BBMV of larvae fed
on diets with Bt was higher as compared to the amounts in the BBMV of the larvae fed on
diet without Bt, indicating the binding of the BI protein to the BBMV, which resulted in
increased protein content in the BBMV.
The insecticidal activity of BI endotoxins depends on the amounts of food ingested by
the target insects. The organic acids (oxalic and malic acids) also act as antifeedents, and
therefore, may reduce the effect of B1 as less amounts of food will be consumed by the larvae.
However, the amounts of oxalic and malic acids impregnated in to the diet did not effect the
 
Date 2009
 
Type Thesis
NonPeerReviewed
 
Format application/pdf
 
Language en
 
Rights —
 
Identifier http://oar.icrisat.org/6077/1/64148.pdf
Surekha Devi, V (2009) Interaction of acid exudates in chickpea with biological activity or cry toxins from Bacillus thuritgiensis berliner against Helicoverpa armigera (hubner). PhD thesis, Acharya N G Ranga Agricultural University.