Morphological and biochemical factors associated with resistance to Maruca vitrata (Lepidoptera: Pyralidae) in short-duration pigeonpea

Abstract

The spotted pod borer Maruca vitrata (Geyer) is known for its economic importance throughout its geographical distribution because of its destructive nature to reproductive parts of several grain legume crops including pigeonpea. In view of the importance of the pest, the present study was carried out on the association of different morpho-chemical traits with resistance/susceptibility to M. vitrata at the International Crops Research Institute for the Semi-Arid Tropics, Patancheru, India. Trichome length and density, sugars, proteins and phenols were found to be associated with resistance to M. vitrata in short-duration pigeonpea genotypes. Pod damage by M. vitrata on different short-duration pigeonpea genotypes in the field ranged from 5.8 to 68%. Laboratory studies showed less consumption of food and reduced larval and pupal weights of M. vitrata when reared on the resistant genotypes ICPL 98003 and ICPL 98008 indicating antibiosis effects of the genotypes. Trichome density on upper and lower surfaces of the leaf (390 and 452/9 mm 2 ), and length (3.5 mm) and trichome density (442/9 mm 2 ) and length (5.9 mm) on pods were found positively correlated with the resistant genotype ICPL 98003. High sugar content in flowers (22%) and pods (10.6%) was responsible for the susceptibility of ICPL 88034, while high phenol concentration in flowers (6.5%) and pods (9.3%) in ICPL 98003 was responsible for resistance. Protein content in pods was significantly higher (25.5%) in susceptible ICPL 88034 when compared with resistant ICPL 98003 (16.5%). Based on these results, ICPL 98003 and ICPL 98008 were categorized as highly resistant and ICPL 98012 as moderately resistant. This paper discusses the physico-chemical traits associated with resistance to M. vitrata in short-duration pigeonpea genotypes.

Conventional and Molecular Approaches towards Genetic Improvement in Pigeonpea for Insects Resistance

“…Pigeonpea pod walls with more wax, total phenols and less reducing and non-reducing sugars and total amino acids ( Table 2) suffers less pod and grain damage by pod fly [47]. Similar findings have been reported for resistance to pod fly [26,55] and H. armigera in wild species [31], and to M. vitrata in cultivated pigeonpea [56].…”

Screening of yard long bean genotypes for resistance to legume pod borer, Maruca vitrata F.

“…In present study it was found that protein content in pods and flowers were significantly higher (29.46 and 22.46%) in susceptible YL 305 compared to moderately resistant Long Red Mollika (21.00 and 15.17%) ( Table 5). Sunitha et al (2008) also observed similar trend that protein content in pods was significantly higher (25.5%) in susceptible ICPL 88034 compared to resistant ICPL 98003 (16.5%) against the M. vitrata in short duration pigeonpea cultivars. Phenol and sugar compounds in the flower and green pods of the yard long bean are not found to contribute resistance against the insect M. vitrata (Table 5).…”

Effect of trichomes in cowpea on infestation by spotted pod borer, Maruca vitrata (Fab.) (Lepidoptera: Crambidae)

“…A significant correlation between trichome length and per cent pod damage could not be observed in the study. Sunitha et al (2006) however, ha d obser ved significa nt negative correlation (-0.097) between trichome length on pods and pod borer damage in pigeon pea. Anaswar a. T he lowest trichome density was recorded in PKM-1 (16.34/6.25 mm 2 ), followed by Bhagyalekshmi, Lola, IC 52105, EC 300039, IC 20645, IC 20431, VellayaniJyothika and Palakkadanthandanpayar with 17.34, 18.34, 18.67, 27.34, 32, 33, 39.34 and 49.34 trichomes per 6.25 mm 2 , r esp ectively.…”