Role of morphological factors of pigeonpea in imparting resistance to spotted pod borer, Maruca vitrata Geyer (Lepidoptera: Crambidae)

Morphological characters of eleven test genotypes of pigeonpea, such as growth habit, pubescence of pods and leaves, pod angle and pod wall thickness were studied in order to work out the relationship of these traits vis-à-vis resistance/susceptibility to Maruca vitrata. It was observed that genotype AL 1747 possessed significantlyhighest trichome density on leaves and pods (177.33 and 43.33 trichomes/4.6cm2, respectively), whereas MN 1 possessed lowest trichome density (47.33 and 7.66 trichomes/4.6cm2, respectively). Trichome length on leaves and pods was significantly highest in AL 1747 (66.26 and 180.83?m, respectively) and lowest in MN 1 (33.53 and 43.25?m, respectively). Genotype AL 1747 recorded significantly highest pod angle (65o), whereas MN 1 recorded lowest pod angle (18.66o). There was significant negative correlation between trichome density on leaves and pods with larval weight gain (r = -0.71 and -0.69, respectively) as well as with per cent pod damage ( r = -0.75 and -0.75, respectively) and between trichome length on leaves and pods with larval weight gain (r = -0.81 and -0.81, respectively) as well as with per cent pod damage (r = -0.87 and -0.87, respectively). Pod angle was found to be significantly negatively correlated with both larval weight gain and per cent pod damage. Thus, early maturing pigeonpea genotypes with indeterminate growth habit, higher leaf and pod pubescence with wider pod angles should be preferred for breeding M. vitrata tolerant lines

Exploring the potential of seed flour from pigeon pea genotypes to retard the growth and development of Helicoverpa armigera

Helicoverpa armigera is one of the most devastating known pest causing major economic losses. Development of insect resistance against chemical pesticides and the environment concerns are forcing researchers to pave way towards biopesticides. Our study aimed to test the efficacy of seed flour from ten pigeon pea genotypes against H. armigera development. H. armigera fed with diet containing pigeon pea seed powder exhibited larval and pupal weight reduction and certain abnormalities. Larval weight reduction varied from 19 % (AL 1495) to 37 % (AL 1677). Increase in larval duration was seen in genotypes containing higher trypsin inhibitor, phenols and phytic acid. AL 1677 was found to be the most resistant genotype with 37 % larval weight reduction followed by AL 1735. Larval-pupal intermediates were observed in diets containing AL 1495 and AL 1747 seed powder. The pupal weight reduction varied from 15.5 % to 44.5 %. Results from this study suggest the inhibitory potential of PIs and other bioactive compounds such as phenols and phytic acid from pigeon pea cultivars against H. armigera development, that can be further exploited in pest management