MOLECULAR CHARACTERIZATION OF CONTRAST GENOTYPES, BIOECOLOGY AND MANAGEMENT OF MAJOR INSECT PESTS OF DOLICHOS BEAN, Lablab purpureus L.
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Title |
MOLECULAR CHARACTERIZATION OF CONTRAST GENOTYPES, BIOECOLOGY AND MANAGEMENT OF MAJOR INSECT PESTS OF DOLICHOS BEAN, Lablab purpureus L.
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Creator |
PRASHANTH, K
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Contributor |
RAJENDRA PRASAD, P
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Subject |
MOLECULAR, CHARACTERIZATION, CONTRAST GENOTYPES, BIOECOLOGY, MANAGEMENT, INSECT PESTS, DOLICHOS BEAN, Lablab purpureus L.
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Description |
The study on the ?Molecular characterization of contrast genotypes, Bioecology and Management of major Insect Pests of Dolichos bean, Lablab purpureus L.? with field experiments conducted during Kharif 2012, Rabi 2012-13, Kharif 2013 and Rabi 2013-14 at S.V. Ag. College Farm, Tirupati to document the seasonal incidence of major pests in different seasons, pest management with new insecticides in field bean and to evaluate field bean genotypes for insect resistance. Studies pertaining to molecular characterization of contrast genotypes of Lablab purpureus L., biology of major insect pests and residue analysis (dissipation patterns) of selected insecticides were undertaken at Institute of Frontier Technology, Regional Agricultural Research Station, Tirupati and AINP on Pesticide Residues, Rajendranagar, Hyderabad, Andhra Pradesh. Among the genotypes of Lablab purpureus L. screened during kharif 2012 and rabi 2012-13, TFB 42, GLB 22, GLB 160, GLB 300, GLB 510, GLB 537 and GLB 550 were resistant to pod borers which can be explored in resistance studies and also in developing new lines. Some genotypes even though categorized under susceptible group gave higher yields inspite of higher per cent pod damage by pod borers, which showed that these genotypes exhibited tolerance to pod borers. Among the morphological characters, pod damage showed highly significant negative (r = -0.96) correlation with pod fragrance and highly significant positive (r = 0.76) correlation with pod length. Among the 12 primers, 9 of them exhibited polymorphism while the other 3 were monomorphic. The RAPD markers produced a total of 49 bands with 61.22 per cent polymorphism. The similarity indices ranged from 0.57 to 0.92 indicating the wide range of genetic diversity at molecular level and phylogenetic relationship among 17 field bean genotypes analyzed using RAPD technique. The cluster analysis showed 6 clusters in which cluster 1 comprised of resistant cultivars whereas susceptible cultivars were grouped under cluster 2, 5 and 6. A total of 27 insect species of 19 families under 6 orders were found to be associated with field bean comprising both pests and natural enemies during crop growth and developmental phase. Among the insect pests with field bean crop, Hemiptera dominated the total insects followed by Lepidoptera and Coleoptera associated during the study period. Seasonal incidence of major pests revealed that Sphenarches reached peak twice in kharif seasons while had only one peak in rabi seasons. Other insects Maruca, Coptosoma, Riptortus and Clavigralla also recorded the single peak in all the seasons. S. caffer, Clavigralla and Maruca showed high to moderate infestation whereas Coptosoma and Riptortus showed moderate to low infestation. Plume moth, Riptortus and Coptosoma incidence commenced soon after flowering where as Maruca and Clavigralla incidence started a month later. Riptortus was major pod sucking bug in kharif crop while, it was Clavigralla in rabi sown crops. Between the cultivars, TLV was more infested than TFB-2 cultivar. Among the major insect pests Sphenarches caffer, Coptosoma cribraria, Riptortus pedestris and Clavigralla gibbosa followed the regular/ uniform distribution in both TFB-2 and TLV cultivars of field bean whereas M. vitrata was distributed in uniform/ aggregate pattern during the study period. Correlation between the weather parameters and insect pest population revealed that insect pest incidence was strongly dependent on maximum and minimum temperatures, which were negatively correlated whereas other weather parameters like morning RH, evening RH, rainfall, number of rainy days, sun shine hours and wind velocity didn?t had more influence on the pest incidence, exceptions were seen in some cases with pod bugs during four seasons studied. The total life cycle of Sphenarches caffer, Maruca vitrata, Coptosoma cribraria and Clavigralla gibbosa i.e. from egg to adult on an average were 35.69, 31.50, 69.07 and 52.06 days, respectively. Novaluron @ 1.0 ml/l was found to be highly effective in reducing the pod borer?s population from 2 days after spraying. This was followed by the rynaxypyr @ 0.3 ml/l, spinosad @ 0.3 ml/l and lambda cyhalothrin @ 2.0 ml/l during the study period whereas imidacloprid @ 0.3 ml/l was effective in bringing down the pod sucking bugs incidence from 2 days after spraying followed by monocrotophos @ 1.6 ml/l, lambda cyhalothrin @ 2.0 ml/l, malathion @ 2.0 ml/l and NSKE 5% during the study period. The highest pod damage and seed damage was observed in untreated check followed by NSKE 5% treated plots while the least pod damage and seed damage was recorded in rynaxypyr @ 0.3 ml/l followed by novaluron @ 1.0 ml/l, spinosad @ 0.3 ml/l and chlorfenapyr @ 2.0 ml/l in all the four seasons studied. The treatment with rynaxypyr @ 0.3 ml/l recorded highest pod yield of 2880.25 and 2520.80 kg ha-1 over untreated check with 1039.58 and 676.58 kg ha-1 followed by the treatments novaluron 2771.50 kg ha-1 and 2418.18 kg ha-1 in both kharif and rabi seasons, respectively. Highest cost benefit ratio of 1: 23.29 and 1: 15.70 was realized with lambda cyhalothrin @ 2ml/l treatment followed by malathion @ 2 ml/l with 1: 20.17 and 1: 10.74 in kharif and rabi seasons. The other promising treatments were imidacloprid @ 0.3 ml/l and monocrotophos @ 1.6 ml/l. Initial deposits of lambda-cyhalothrin, chlorantraniliprole, imidacloprid and monocrotophos was 1.02, 8.13, 0.57 and 1.59 mg kg-1 but dissipated to below determination levels (BDL) by 8, >10, 10 and 10 days, respectively. The half life of lambda-cyhalothrin, chlorantraniliprole, imidacloprid and monocrotophos on field bean samples analysed was 6.66, 1.01, 0.75 and 5.33 days while the safe waiting period of these insecticides were 8, 10, 10 and >10 days as per BDL levels, respectively. |
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Date |
2016-11-14T10:46:29Z
2016-11-14T10:46:29Z 2014 |
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Type |
Thesis
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Identifier |
312p.
http://krishikosh.egranth.ac.in/handle/1/85344 |
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Language |
en_US
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Relation |
D5025;
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Format |
application/pdf
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Publisher |
ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY
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