Studies on biophysical basis of resistance in pigeonpea genotypes against pod borer complex
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Date
2016-08
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The present investigation was carried out at Norman E. Borlaug Crop Research Centre, G.B. Pant University of Agriculture and Technology, Pantnagar during 2015-16. Twenty five species of insect pests were found to attack the pigeonpea genotypes among which five insect pests attained major pest status viz., Empoasca kerri Pruthi, Grapholitica critica Meyr., Maruca vitrata (Geyer), Clavigralla gibbosa Spinola and Melanagrmyza obtusa (Malloch). Eleven natural enemies were also found associated with the insect pest complex, among which Eocantheocona furcellata (Wolff.) was identified as a potential predator of M. vitrata, G. critica and Spodoptera litura.
Incidence of insect pests of pigeonea was studied from 31st SW to 52nd SW. M. vitrata and M. obtusa were found to be dominant pests among the pod borer complex incidence of the predatory bugs was studied from 38th SW to 47th SW maximum population of E. furcellata (5.8 bugs/m2) and R. fuscipes (1.4 bugs/m2) were observed during 42nd SW and 41st SW respectively.
Result of screening of thirty one pigeonpea genotypes with three checks against pod borer complex revealed that two genotypes was found to be highly resistant, seven genotypes found highly susceptible, eight genotypes was found moderately susceptible and seventeen genotypes was found least susceptible to M. vitrata damage. In case of H. armigera seven genotypes was found highly susceptible, thirteen genotypes was found to be moderately susceptible and nine genotypes was found to be least susceptible to H. armigera damage. While ten genotypes was found highly susceptible, nine genotypes was found moderately susceptible and twelve genotypes was found least susceptible to M. obtusa damage over the checks cultivars PA 291, PUSA 992 and UPAS 120.
Results on morphological characters revealed that the pod length of pigeonpea genotypes varied from 50.71 mm to 61.53 mm, pod width varied from 6.42 mm to 8.37 mm, pod wall thickness varied from 0.33 mm to 0.48 mm, number of grains per pod varied from 3.28 grains to 4.16 grains, number of pod per plant varied from 27.4 pods/plant to 94 pods/plant, trichomes density on pod varied from 257/9mm2 to 324.4/9mm2 and days to flowering varied from 74 days to 78 days. Correlation studies of morphological characters with pod damage per cent revealed that some genotypes having greater pod length, greater width and thicker pod wall suffered less damage, whereas, no significant role of trichomes density on pod, number of pod/plant and number of grains/pod was reported on pod damage of genotypes.
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