Mechanisms of resistance against Helicoverpa armigera in Pigeonpea

Views:
 
     
 

Presentation Description

No description available.

Comments

Presentation Transcript

PowerPoint Presentation:

Mechanisms of resistance against Helicoverpa armigera in Pigeonpea

PowerPoint Presentation:

INTRODUCTION

PowerPoint Presentation:

Pigeonpea [ Cajanus cajan (L.) Millsp.] is an important pulse crop, known as red gram, the common name; tur, the Gujarati name and arhar, the Hindi name, is the fifth prominent pulse crop in the world and second most important grain legume in India after gram. It belongs to the family Leguminoseae, tribe Phaseoleae and Sub-tribe Cajaninae. Pigeonpea is an important component of human nutrition particularly in vegetarian based diets. Its food value is the most essential due to protein content (22.3 %) and also rich in iron, iodine, and essential amino acids like lysine, tyrosine and arginine. Having a wide adaptability to climate, soil and also good resistance to drought, it is widely cultivated under semi-arid conditions of India, sharing 90 per cent of total world production.

PowerPoint Presentation:

Area Production Productivity Year India 3.73 Million ha 2.80 Million tones 776 kg/ha 2007-08 (Anon, 2007-08) Gujarat 0.257 Million ha 0.215 Million tones 838 Kg/ha 2006-07 (Anon, 2007-08)

PowerPoint Presentation:

The national average productivity of this crop is only 776 kg/ha, which is very low as compared to its potentiality. There are several factors which limits its yield, such as cultivation in poor soil, damage due to insect pests and diseases, unfavorable weather conditions during crop period, cultivation of low yielding traditional varieties etc. Of all these factors, insect pest is a major limiting factor for its low production. Pigeonpea crop is prone to pest damage right from sowing to harvesting and also during storage. As a result of insect damage, farmers are not able to realize full yield potential of the crop. Among the various insect-pests, pod borer complex viz., H. armigera, E. atomosa and M. obtusa cause heavy damage to pods resulting in extensive loss in grain yield.

PowerPoint Presentation:

Among the pod borers, H. armigera is a cosmopolitan species and polyphagous in nature, attacking on 181 host plants including pigeonpea, in India ( Manjunath et al ., 1989) . The losses in yield due to H. armigera were reported to the tune of 43.20 percent ( Bhatnagar et al ., 1982). In Gujarat, the pod damage due to H. armigera has been reported 39.20 per cent in the variety BDN-2 (Patel and Patel, 1990). To overcome the problem of heavy losses in yield due to pod borers in pigeonpea, farmers are using excessive and frequent application of pesticides, which make pigeonpea cultivation quite expensive. Besides this the frequent exposure of H. armigrea that too with higher concentration developed resistance to insecticides and created several other problems like destruction of beneficial bioagents and pollinators, toxic residues, environmental pollution, pest resurgence etc.

PowerPoint Presentation:

It is therefore necessary to device a sound IPM programme which should be ecologically and economically viable (Saxena and Khan, 1991). The use of resistant cultivars to the major insect pests is main component of IPM particularly under subsistence farming in developing countries. Host plant resistance to insect pest is an economically and ecologically preferred alternative as compared to other pest management strategies, particularly the synthetic pesticides. Commonly accepted definition of host plant resistance given by Painter (1951) as, “the relative amount of heritable qualities possessed by a plant which influence the ultimate degree of damage done by the insect in the field.”

HISTORY:

HISTORY 1782: ‘Underhill’ variety of wheat reported to show some resistance to Hessian fly. 1831: ‘Winter Majetin’ variety of apple reported to be resistant to apple woolly aphid. 1861: C.V. Riley grafted American rootstocks on European grapes resistant to grape phylloxera (introduced from N. America). 1914: At Kansas State University R.H. Painter began breeding efforts for the scientific development of cultivars resistant to Hessian fly. Painter is widely recognized as the “Father of Host Plant Resistance.” 1955: Parnell, In Africa found a single hairy cotton plant which was not affected by jassids , Empoasca spp. and later on the variety was developed from that single plant and named as “U-4” variety.

PowerPoint Presentation:

Resistance Preference/ Non-preference Tolerance Antibiosis

PowerPoint Presentation:

Non-preference :- Non-preference refers to plant characteristics that lead insects away from a particular host. Recently, the term antixenosis , has been suggested as a more appropriate term for non-preference. Xenosis in Greek means "Guest", and antixenosis means against or expelling guests. Non-preference in a cultivar may have either a allelochemical or morphological basis. Allelochemicals are chemicals used in inter-specific communication. Allelochemic non-preference : Non-preference of the host is because of the presence or absence of allelochemicals . Morphological non-preference: Non-preference results from plant structural characteristics that interfere with normal behavior of insects.

PowerPoint Presentation:

Bases of resistance A number of plant characteristics are known to render the cultivars less susceptible or unable for feeding, oviposition and development of insect pests. These characteristics can be classified into two categories i.e. biophysical and biochemical. 1) Biophysical bases (Morphological bases):- Morphological characters imparts resistance against insect by interfering physically with locomotory mechanism more specially with mechanism of host selection, feeding, ingestion, digestion, mating and oviposition . Two factors responsible for morphological defense, i ) Remote factors ii) Contact factors i ) Remote factors :- Colour , shape, and size of plant effect host selection behavior of phytophagous insects and associated with some resistance. E.g. Helicoverpa armigera attracted towards yellow plants than green plants when both are grown together.

PowerPoint Presentation:

Antibiosis :- Antibiosis refers to all adverse effects on the insect life history which result when a resistant host plant variety or species is used for food. Some effects of antibiosis mode of resistance are: Reduced survival Reduced growth rate. Insects take longer time to complete the life cycle. Reduced weight and size. Reduced fecundity. Morphological abnormalities. Allelochemicals are generally associated with antibiosis. Tolerance :- Tolerance includes all plant responses resulting in the ability to withstand insect infestations and yield satisfactorily in spite of injury levels that would debilitate non-resistant plants. Unlike non-preference and antibiosis, only plant response is involved in tolerance. Some of the components of tolerance mechanism are : General vigour , Compensatory growth in infested plants, Quick wound healing, Changes in photosynthetic partitioning, Mechanical support in tissues and organs.

PowerPoint Presentation:

Pods damaged by pod borer Male (down) and female (above) pod borer adults H. armigera damaging pigeonpea leaves and pods H. armigera eggs on pigeonpea flower buds Helicoverpa larva damaging pigeonpea pod. H. armigera eggs on pigeonpea leaves

PowerPoint Presentation:

To understand host resistance to insects, recognizing the components of insect-host interactions is important, Steps in host utilization by insects: Host habitat finding and host finding Host recognition Host acceptance Host suitability Plant resistance to insects might be influenced by altering any of these components. 1. Host habitat finding and host finding :- Green or yellow colors for aphids and whiteflies Volatile chemicals (semiochemicals) Temperature or humidity

PowerPoint Presentation:

2. Host recognition / acceptance :- Tactile characteristics Chemical exudates Plant structures, textures, tastes 3. Host suitability :- Nutritional quality Absence of toxic compounds Components that allow normal development and fecundity

PowerPoint Presentation:

Bases of resistance A number of plant characteristics are known to render the cultivars less susceptible or unable for feeding, oviposition and development of insect pests. These characteristics can be classified into two categories i.e. biophysical and biochemical. 1) Biophysical bases (Morphological bases):- Morphological characters imparts resistance against insect by interfering physically with locomotory mechanism more specially with mechanism of host selection, feeding, ingestion, digestion, mating and oviposition . Two factors responsible for morphological defense, i ) Remote factors ii) Contact factors i ) Remote factors :- Colour , shape, and size of plant effect host selection behavior of phytophagous insects and associated with some resistance. E.g. Helicoverpa armigera attracted towards yellow plants than green plants when both are grown together.

PowerPoint Presentation:

Cajanus scarabaeoides Cajanus cajanifolius Cajanus lanceolatus Wild Genotypes of Pigeonpea Rhyncosia aurea Rhyncocia bracteata Rhyncosia canna

PowerPoint Presentation:

Rhyncosia Minima Cajanus platycarpus Rhyncosia suaveolence Rhyncosia rufescence Rhyncosia rothi

PowerPoint Presentation:

C. scarabaeoides C. cajanifolius C. rufescence R. suaveolence R. bracteata R. canna R. aurea C. platycarpus R.minima Radhanpur local R. rothi

PowerPoint Presentation:

ICD-9135 ICD-9140 ICD-11488 ICD-11912 ICD-12012 ICD-12116 ICD-13092 ICD-13555 Indo-African cross derivatives of Pigeonpea

PowerPoint Presentation:

ICD-9135 ICD-9140 ICD-11488 ICD-11912 ICD-12012 ICD-12116 ICD-13092 ICD-13555

PowerPoint Presentation:

Fig. 1 Distribution of eggs of Helicoverpa armigera on different varieties of pigeonpea. Oviposition non-preference APAU, Lam Rao et al. (1991)

Table 1. Ovipositional preference by H. armigera for various genotypes/cultivars of pigeonpea. :

Table 1. Ovipositional preference by H. armigera for various genotypes/cultivars of pigeonpea. Genotypes/Cultivars Plant type Avg. No. of eggs laid/twig Oviposition (%) T 21 IDT 7.00 6.16 BDN 2 IDT 12.67 11.14 ICPL 13207 IDT 9.67 8.50 GAUT 82-90 IDT 9.67 8.50 34.30 ICPL-87 DT 21.33 18.77 GAUT 82-104 DT 17.67 15.55 ANDT-I DT 15.33 13.49 ANDT-II DT 20.33 17.89 65.70 G.M. 14.21 S.Em.± 1.48 C.D. at 5% 4.49 C.V. % 29.44 Anand Dodia (1992)

PowerPoint Presentation:

Oviposition non-preference Fig.2 Egg laying by H. armigera Hubner on six short-duration pigeonpea genotypes. ICRISAT Sison et al. (1992)

Table 2. Oviposition abundance of Helicoverpa armigera on pigeonpea and its wild relatives under multi-choice field conditions. :

Table 2. Oviposition abundance of Helicoverpa armigera on pigeonpea and its wild relatives under multi-choice field conditions. Sr. No. Genotype No. of eggs/10 inflorescence Sr. No. Genotype No. of eggs/10 inflorescence 1 ICPW 68 ( C. platycarpus ) 0.00 14 C. cajanifolius 0.00 2 ICPW 83 ( C. scarabaeoides ) 0.00 15 C. sericeus 0.00 3 ICPW 90 ( C. scarabaeoides ) 0.00 16 C. Scarabaeoides Sel-1 0.00 4 ICPW 94 ( C. scarabaeoides ) 0.00 17 Rhyncosia bracteata 9.14 5 ICPW 116 ( C. scarabaeoides ) 0.00 18 C. albicans 9.14 6 ICPW 125 ( C. scarabaeoides ) 0.00 C. cajan 7 ICPW 130 ( C. scarabaeoides ) 0.00 19 ICPL 332 12 8 ICPW 137 ( C. scarabaeoides ) 0.00 20 ICPL 7203-1 43 9 ICPW 141 ( C. scarabaeoides ) 0.00 21 ICPL 84060 29 10 ICPW 152 ( C. scarabaeoides ) 0.00 22 ICPL 187-1 39 11 ICPW 278 ( C. scarabaeoides ) 0.00 23 ICPL 87-check 69 12 ICPW 280 ( C. scarabaeoides ) 0.00 Mean 9.14 13 ICPW 281 ( C. scarabaeoides ) 0.00 S.Em.± ±0.39 ICRISAT Anonymous (2001)

Table 3. Ovipositional non-preference and antibiosis in H. armigera on pigeonpea.:

Table 3. Ovipositional non-preference and antibiosis in H. armigera on pigeonpea. Entries Ovipositional non-preference Antibiosis Field condition Lab condition Larval mortality % within 7 days Larval weight (mg) Larval period (days) Eggs/infl-orescence No. of eggs on 3 twigs % Oviposition LRG-41 0.40 17 15.0 45 294 32.0 VRG-17 0.38 20 17.7 40 234 31.6 ICPL-332 0.50 20 17.7 45 260 32.6 BDN-2(L. Ch.) 0.80 33 29.2 20 338 29.1 ICPL-87119 0.80 23 20.4 25 340 29.6 Sardarkrushinagar Anonymous (2004a)

Table 4. Mechanism of resistance of certain pigeonpea entries against H. armigera:

Table 4. Mechanism of resistance of certain pigeonpea entries against H. armigera Entries Pod borer damage (%) Total no. of eggs laid/5 females Larval wt. after 7 days (gm) Larval wt. after 12 days (gm) Pupal weight (gm) ICPL-87119 31.0 81 0.20 0.20 0.21 ICPL-332 16.6 70 0.15 0.19 0.20 CO-5 43.0 136 0.13 0.22 0.22 CO-6 18.3 62 0.11 0.18 0.18 LRG-41 12.5 51 0.12 0.18 0.19 VRG-17 14.7 65 0.15 0.22 0.21 Coimbatore Anonymous (2004b)

Table 5. Mechanism of resistance against H. armigera.:

Table 5. Mechanism of resistance against H. armigera . Genotypes Under field conditions Under laboratory conditions % Larval mortality one week after release No .of eggs/5 twigs No. of eggs after 3 days 3 DAT 6 DAT 9 DAT Abhay 6.7 21.3 19.3 9.0 76.7 VRG-17 7.7 24.3 22.3 10.3 86.7 WRG-55 11.0 26 31.3 13.7 96.7 WRG-27 14.3 22.3 27.3 14.0 100.0 LRG-41 11.0 21.3 36 12.7 93.3 LRG-30 11.3 26.3 29.3 16.0 93.3 ICPL-87119 17.3 26.7 26.7 18.7 76.7 S.Em.± 0.92 0.94 0.73 1.37 6.40 C.D. at 5% 2.8 2.9 2.3 4.2 19.7 Warangal Anonymous (2004b)

Table 6. Non-preference, antibiosis and tolerance against Helicoverpa armigera in pigeonpea cultivars.:

Table 6. Non-preference, antibiosis and tolerance against Helicoverpa armigera in pigeonpea cultivars. Entries No. of eggs laid/5 female (caged) % pod borer damage by H. armigera 10 Larval weight at 7 days (gm) 10 Pupal weight (gm) LRG 30 86 10.3 0.21 0.21 LRG 41 61 15.1 0.15 0.19 ICPL 87119 91 12.4 0.20 0.22 VRG 17 85 6.3 0.19 0.21 ICPL 332 80 5.5 0.15 0.21 Guntur Anonymous (2005b)

Table 7. Ovipositional non-preference of Helicoverpa on certain pigeonpea entries.:

Table 7. Ovipositional non-preference of Helicoverpa on certain pigeonpea entries. Entry Total no. of eggs laid / 5 female 2003 2004 Mean ICPL 87119 81 231.6 156.3 VRG 17 65 130.0 97.5 ICPL 332 70 169.7 119.8 CO 5 136 233.3 184.7 LRG 41 51 75.1 63.1 Coimbatore Anonymous (2005b)

Table 8. Preference and non-preference of Helicoverpa armigera under field and laboratory conditions.:

Table 8. Preference and non-preference of Helicoverpa armigera under field and laboratory conditions. Genotypes Under field condition Under laboratory condition No. of eggs/plant at 50% flowering No. of eggs laid/twig (after 3 days) LRG-30 12.07 10.00 LRG-41 11.33 7.33 WRG-27 8.00 7.00 WRG-55 10.07 9.00 VRG-17 10.66 7.33 ICPL-87119 9.73 13.00 Abhay 13.20 7.00 S.Em.± 0.648 0.490 C.D. at 5% 2.79 1.51 Warangal Anonymous (2005b)

Ovipositional preference:

Ovipositional preference Khargone Anonymous (2004b) Fig.3 Ovipositional preference by H. armigera females on pigeonpea genotypes under field conditions.

Table 9. Ovipositional preference of Helicoverpa armigera on various Indo-African cross derivatives under cage conditions. :

Table 9. Ovipositional preference of Helicoverpa armigera on various Indo-African cross derivatives under cage conditions. Sr. No. Variety Average No. of eggs laid / plant % Oviposition 1 ICD-9135 9.33 3.45 2 ICD-9140 16.67 6.18 3 ICD-9145 8.33 3.09 4 ICD-11488 13.0 4.82 5 ICD-11912 40.67 15.08 6 ICD-12012 19.0 7.05 7 ICD-12116 25.0 9.27 8 ICD-13092 78.0 28.92 9 ICD-13555 59.67 22.13 Sardarkrushinagar Anonymous (2006a)

Table 10. Growth and development of Helicoverpa armigera on different varieties of pigeonpea. :

Table 10. Growth and development of Helicoverpa armigera on different varieties of pigeonpea. Larval mass (mg) Larval period (days) Pupal mass (mg) Pupal period(days) Larval mortality (%) Larvae pupated (%) Adult emergence (%) Avg. no. of eggs female Growth index Developing pods BDN 2 471 22.1 288 14.1 16.7 60.0 46.7 796 2.72 ICPL 270 346 25.4 248 17.0 20.0 53.3 40.0 556 2.10 ICPL 84060 322 27.2 244 16.9 23.3 43.3 36.7 643 1.60 Mean 378 24.6 262 15.6 20.0 52.2 41.1 665 2.14 CD at 5% 30.6 1.3 16.5 1.2 - - - - - Flowers BDN 2 378 21.5 262 13.7 10.0 73.3 60.0 943 3.40 ICPL 270 371 22.1 257 14.1 10.0 70.0 50.0 713 3.17 ICPL 84060 430 21.8 271 13.8 6.6 66.7 56.7 712 3.07 Mean 393 21.8 263 13.9 8.9 70.0 55.6 789 3.21 CD at 5% 21.9 NS NS NS - - - - - Anand Dodia et al. (1994) Measured on the 19 th day after hatching, Up to 7 days after hatching NS = Non significant

Table 11. Growth and development of Helicoverpa armigera on different Cajanus species. :

Table 11. Growth and development of Helicoverpa armigera on different Cajanus species. Treatment (hosts) Larval weight (mg) Larval period (days) Pupal weight (mg) Pupal length (cm) Pupal period (days) Larval mortality(%) Larvae pupated (%) Adult emer-gence Growth index C. Scarabaeioides 57 41.60 161 1.72 16.60 80.00 20 20 0.48 C. Cajanifolius 145 35.49 154 1.66 19.75 44.00 48 32 1.36 C. reticulatus 85 35.75 128 1.41 19.00 48.00 52 32 1.45 C. serieus 61 43.86 176 1.64 15.14 68.00 32 28 0.73 Rhinchosia rothi 143 35.23 174 1.70 19.70 52.00 44 40 1.25 F1 ( C. scarabaeioides × C. cajan ) 102 38.92 165 1.64 17.00 32.00 60 44 1.54 C. cajan 212 30.22 293 2.02 15.80 23.77 76.92 60 2.55 GM 120 36.84 171 1.68 17.80 49.68 47.56 36.57 - S.Em. ± ± 18 ± 1.16 ± 14 ± 0.36 ± 0.57 - - - - C.D. at 5% 50 3.31 40 0.102 1.61 - - - - C.V.(%) 45.64 9.02 24.19 6.61 8.52 - - - - Sardarkrushinagar Dodia et al. (1996) Larval mortality (%) 7 days after hatching.

Table 12. Growth and development of H. armigera on pigeonpea genotypes under field conditions (Antibiosis).:

Table 12. Growth and development of H. armigera on pigeonpea genotypes under field conditions (Antibiosis). Genotypes Larval weight (gm) Larval period (days) Pupal weight (gm) Pupal period (days) LRG-41 0.147 18.8 0.152 22.2 VRG-17 0.138 30.8 0.184 17.8 ICPL-332 0.134 23.8 0.194 22.2 Khargone-2 (LCh) 0.111 24.2 0.152 20.4 Asha 0.080 32.6 0.120 16.8 C-11 (NCh) 0.113 25.6 0.144 24 S.Em.± 0.024 0.524 0.003 0.457 C.D. at 5% NS 1.54 0.01 1.34 Khargone Anonymous (2004b)

Table 13. Antibiotic effect of certain pigeonpea entries against Helicoverpa.:

Table 13. Antibiotic effect of certain pigeonpea entries against Helicoverpa . Entry Larval weight 0n 7 th days (gm) Larval weight on 12 th days (gm) Pupal weight (gm) 2003 2004 Mean 2003 2004 Mean 2003 2004 Mean ICPL 332 0.148 0.177 0.163 0.194 0.294 0.244 0.201 0.243 0.222 CO 5 0.128 0.209 0.168 0.221 0.320 0.271 0.217 0.259 0.238 ICPL 87119 0.195 0.319 0.257 0.204 0.495 0.349 0.210 0.363 0.286 VRG 17 0.151 0.152 0.152 0.217 0.261 0.239 0.210 0.228 0.219 LRG 41 0.115 0.133 0.124 0.176 0.229 0.203 0.194 0.159 0.176 Coimbatore Anonymous (2005b)

Table 14. Growth and development of Helicoverpa armigera on pigeonpea and correlation with antinutritional factors.:

Table 14. Growth and development of Helicoverpa armigera on pigeonpea and correlation with antinutritional factors. Treatment Larval period (days) Larval weight (mg) Pupal period (days) Pupal weight (mg) Larval mortality (%) Growth index Tannin (%) Phenol (%) C. cajan 30.22 212 15.80 293 23.77 2.55 0.73 0.96 C. cajanifolius 35.49 145 19.75 154 44 1.36 1.97 2.20 C. scarabaeioides 41.60 57 16.00 161 80 0.48 2.02 3.72 F1 ( C. scarabaeioides × C. cajan ) 38.92 102 17.00 165 32 1.54 1.96 1.57 C.D. at 5% ‘r’ value 4.11 63 1.63 41 - - - - Tannin 0.87 -0.86 0.56 -0.99 0.60 -0.86 - - Phenol 0.80 -0.83 0.161* -0.65 0.99 -0.55 - - Sardarkrushinagar Dodia et al. (2005) * Non significant

Table 15. Growth and development of Helicoverpa armigera on pigeonpea genotypes under field conditions. :

Table 15. Growth and development of Helicoverpa armigera on pigeonpea genotypes under field conditions. Genotypes Larval weight (gm) Larval period (days) Pupal weight (gm) Pupal period (days) LRG-41 0.203 7.16 0.167 11.83 VRG-17 0.173 14.00 0.269 10.00 ICPL-332 0.173 7.33 0.311 10.16 Khargone-2 (LCh) 0.170 8.16 0.221 10.16 Asha 0.162 14.16 0.040 9.16 C-11 0.172 10.16 0.042 12.00 SEm± 0.007 0.483 0.009 0.303 CD at 5% 0.020 1.407 0.025 0.883 Khargone Anonymous (2005b)

Table 16. Growth and development of Helicoverpa armigera on different varieties of pigeonpea. :

Table 16. Growth and development of Helicoverpa armigera on different varieties of pigeonpea. Sr. No. Variety Larval weight (mg) Larval period (days) Pupal wt. (mg) Pupal length (cm) Total free amino acid (mg/g) Total soluble sugar (%) Total phenol(mg/g) Total tannin (%) 1 LRG-41 259 32.10 298 1.78 7.41 6.95 1.51 4.40 2 ICPL-332 242 32.62 261 1.74 9.18 7.11 1.15 3.36 3 VRG-17 267 32.06 285 1.67 7.57 7.25 1.87 3.87 4 ICPL-87119 373 30.5 303 1.85 10.30 6.55 1.65 3.87 5 GT-1 344 31.5 293 1.84 8.38 8.78 1.15 2.18 6 BDN-2 389 30.41 314 1.88 9.66 8.45 1.07 2.23 Sardarkrushinagar Anonymous (2005a)

PowerPoint Presentation:

Fig.4 Growth and development of Helicoverpa armigera on different varieties of pigeonpea. Antibiosis Sardarkrushinagar Anonymous (2006b)

PowerPoint Presentation:

Fig.5 Antibiosis effect of resistant genotypes against Helicoverpa armigera. Sardarkrushinagar Anonymous (2008) Antibiosis

Table 17. Antibiosis and tolerance against Helicoverpa armigera.:

Table 17. Antibiosis and tolerance against Helicoverpa armigera . Genotypes Antibiosis Tolerance % Mortality of larvae Pupal weight (gm) Pupal period (days) No. of pods/45 cm twig % pod damage LRG-30 50.00 218 18 41 7.35 LRG-41 56.67 199 20 40 4.23 WRG-27 66.67 287 18 34 6.71 WRG-55 50.00 221 19 41 7.09 VRG-17 70.00 266 18 31 7.40 ICPL-87119 53.33 215 18 25 12.63 ICPL-332 50.00 214 21 22 24.49 Warangal Anonymous (2004b)

Table 18. Mechanism of resistance against Helicoverpa armigera in pigeon pea, Tolerance. :

Table 18. Mechanism of resistance against Helicoverpa armigera in pigeon pea, Tolerance. Sr.No. Variety Pod borer damage % Yield Untreated Treated Untreated Treated 1 LRG-41 3.90 2.07 882 952 2 ICPL-332 5.82 3.81 1002 1104 3 VRG-17 4.91 4.70 835 1019 4 ICPL-87119 8.57 6.02 905 1301 5 GT-1 10.72 6.51 808 1232 6 BDN-2 13.14 5.17 900 1402 Sardarkrushinagar Anonymous (2005a)

Table 19. Mechanism of resistance against Helicoverpa armigera in pigeonpea, Tolerance. :

Table 19. Mechanism of resistance against Helicoverpa armigera in pigeonpea, Tolerance. Sr.No. Variety Pod borer damage % Yield (kg/ha) Untreated Treated Untreated Treated 1 LRG-41 4.71 3.02 990 1080 2 VRG-17 6.92 3.81 1008 1307 3 ICPL-332 5.78 2.00 887 1171 4 ICPL-87119 11.33 6.80 1000 1405 5 BDN-2 16.18 7.51 958 1308 Sardarkrushinagar Anonymous (2006b)

PowerPoint Presentation:

Wild relatives of pigeonpea are highly resistant to Helicoverpa armigera. Selection of varieties with specific morphological and biochemical composition can be used to select for resistance to Helicoverpa. Biochemical constituents reflects adverse effects on insect biology in the form of reduced fecundity, decreased size, abnormal length of life and increased mortality. To propose an alternative strategy to manage pest effectively, knowledge of insect behavior is essential. On the basis of whole presentation knowledge of resistance mechanism can be incorporated to develope resistant genotypes against Helicoverpa armigera in Pigeonpea. CONCLUSION

PowerPoint Presentation:

Thank You

authorStream Live Help