Phenological traits and photosynthetic pigments interfere in preference and biological fitness of Chilo partellus (Swinhoe) in diverse maize lines

Maize genotypes with diverse morpho-physiological traits exhibit varying levels of resistance to Chilo partellus . This study explored the developmental biology of C. partellus across thirty maize lines to determine their antibiosis effects. Additionally, the role of photosynthetic pigments in conferring resistance or susceptibility to C. partellus was investigated. The results revealed significant variations in the bionomics of C. partellus when fed on different maize lines. Notably, the preference of C. partellus neonates, the extent of damage, and plant phenological traits varied significantly among the tested maize lines. Photosynthetic pigments, including chlorophyll A, chlorophyll B, total chlorophyll, and total carotenoids, showed significant variation under both healthy and stem borer-damaged conditions across all tested A- and R-lines. Stem borer damage led to a marked decrease in these pigments across the maize lines. Longer developmental durations, lower survival rates, reduced pupal weight, and decreased fecundity of C. partellus was observed on the maize lines such as A-lines CML 565, AI 501, DDM 2309-O, PDIM 639, C 70, and R-lines AI 125 and AI 542, including the resistant check CML 442. Photosynthetic pigments and resistance showed a strong and negative association that accounted for 54% and 50% of the variation in C. partellus preference index and antibiosis index, respectively. The R-lines AI 125 and AI 542, as well as the A-lines CML 565, AI 501, and DDM 2309-O, were found to have antibiosis resistance mechanism against C. partellus and show potential for application in maize improvement initiatives.