Improved method of screening maize germplasm for resistance against Chilo partellus (Swinhoe)

Thirty diverse maize genotypes were evaluated by infesting them artificially by stem borer (Chilo partellus) under field conditions during kharif, 2014. The stem borer infestation was measured in terms of leaf injury rating (LIR), dead hearts and stem tunneling. The damage by C. partellus indicated significant differences among the genotypes in respect of all the three traits measured. The leaf injury rating ranged from 2.16 in PFSR51016/1 to 8.74 in HKI 1352. The genotype WNZPBTL2 recorded minimum (14.03%) dead hearts while the genotypes HKI 1378 recorded maximum (55.94%) dead hearts. The larval feeding inside the stem resulted in minimum stem tunneling in WNZPBTL2 and maximum in Basi local i.e., 13.75 and 44.75% respectively. The correlations among damage parameters revealed significant positive association of leaf injury with dead hearts and stem tunneling. Thus these traits proved to be visual indicators of stem borer resistance. A selection index was constructed Division of Entomology, Indian Agricultural Research Institute, New Delhi 110012 India based on LIR and percent stem tunneling for selecting the best genotypes in the test population. The selection index led to the identification of WNZPBTL2 and PFSR 51016/1 as the resistance sources for C. partellus.