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<p>Varietal differences in resistance to African pink stem borer, <i>Sesamia calamistis</i> Hampson among early- and extra-early-maturing open-pollinated maize varieties were investigated to determine the underlying resistance mechanisms and their biochemical basis. Twenty early-maturing and 20 extra early-maturing maize varieties were evaluated against 3rd instar <i>S. calamistis</i> larvae in the screenhouse and based on their performance (visual damage rating, dead hearts, length of stem tunnelled and proportion of stems tunnelled) they were categorised into three groups; resistant, moderately resistant and susceptible. The reproductive success of <i>S. calamistis</i> was assessed on three representatives of each performance category and results showed that the number of eggs laid (199–224) was comparable indicating limited anti-oviposition activity (antixenosis). However, egg viability, larval survival, and adult emergence reduced significantly (<i>p</i> &lt; 0.05) on resistant maize. Also, the development time was prolonged significantly and progeny sex ratio was more male-biased on resistant maize varieties, demonstrating strong antibiosis. Biochemical analyses revealed higher concentration of secondary metabolites (flavonoids, alkaloids, and phenols) in resistant maize groups compared to the susceptible ones. Significant negative relationship existed between the secondary metabolites and damage parameters in the screenhouse and in the field. The implications of obtained results for control interventions were discussed. These findings indicate that several extra-early-maturing varieties, notably TZEE-W Pop STR C5 and TZEE-Y Pop STR C5, combine short growth cycles with strong borer resistance and high flavonoid content, providing farmers and breeders with low-input, climate-adapted options for stem borer management.</p>

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Varietal differences among early and extra-early open pollinated maize infested with the African pink stem borer, Sesamia calamistis Hampson: an impetus for effective borer control

  • 期刊论文

  • 发表日期：

    2026年6月22日

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  • Adeoluwa O. Adeleye,
  • Mosudi B. Sosan,
  • Olalekan J. Soyelu,
  • Raphael E. Okonji

摘要

Varietal differences in resistance to African pink stem borer, Sesamia calamistis Hampson among early- and extra-early-maturing open-pollinated maize varieties were investigated to determine the underlying resistance mechanisms and their biochemical basis. Twenty early-maturing and 20 extra early-maturing maize varieties were evaluated against 3rd instar S. calamistis larvae in the screenhouse and based on their performance (visual damage rating, dead hearts, length of stem tunnelled and proportion of stems tunnelled) they were categorised into three groups; resistant, moderately resistant and susceptible. The reproductive success of S. calamistis was assessed on three representatives of each performance category and results showed that the number of eggs laid (199–224) was comparable indicating limited anti-oviposition activity (antixenosis). However, egg viability, larval survival, and adult emergence reduced significantly (p < 0.05) on resistant maize. Also, the development time was prolonged significantly and progeny sex ratio was more male-biased on resistant maize varieties, demonstrating strong antibiosis. Biochemical analyses revealed higher concentration of secondary metabolites (flavonoids, alkaloids, and phenols) in resistant maize groups compared to the susceptible ones. Significant negative relationship existed between the secondary metabolites and damage parameters in the screenhouse and in the field. The implications of obtained results for control interventions were discussed. These findings indicate that several extra-early-maturing varieties, notably TZEE-W Pop STR C5 and TZEE-Y Pop STR C5, combine short growth cycles with strong borer resistance and high flavonoid content, providing farmers and breeders with low-input, climate-adapted options for stem borer management.