抽象的

Assessment of varietal susceptibility of maize to the lepidopterous stem borer

Temitayo Akintibu*, Alao FJ, Matanmi BA

Lepidopterous stem borer attack is a major biotic constraint to maize production in Nigeria and by far the most injurious. Continuous investigation of field pests of maize is necessary and screening on the field of various maize varieties available becomes imperative for detail determination of its pests so as to formulate adequate control strategies. This study was conducted to evaluate the relative susceptibility of selected maize varieties to Lepidopterous Stem Borer and to elucidate relationships between yield traits and the stem borer. Nine varieties of maize were planted and ten cobs per varieties were randomly selected at harvesting and bulk together in an envelope. Data collected was subjected to analysis of variance and correlation analysis.

The results revealed that varieties of maize had significant effects on most of the maize grain yield parameters in which varieties TZEE-WSRBC5, BR9928-DMRSR, BR9943-OMRSR and POOL18SRQPM with short cob length and longer ear tip, lower number of kernels per row had higher number of borers per ear and relatively lower grain yield while varieties TZE COMP3 and POP66SRACRa/SUWAN1-SR with longer cob and very reduced ear tip length, higher number of kernels per row couple with reduced borer produce significant high grain yield. BUSOLA-STR variety had a high stem borers infestation with short cob length and longer ear tip but still with high kernels per row and high grain yield may be due to its genetic tolerance while FETZEE-WSTR had the reverse but with lower grain yield which may be due to genetic make-up and some physiological effects. It was also revealed that ear tip length exhibited a significant (P<0.01) positive relationship with number of stem bores (0.782), and length of cob and number of stem borers had positive and negative significant relationship on grain yield respectively (0.623,-0.636).

It can be concluded that five maize varieties with longer ear tip, lower number of kernels per row even including does that were breed for stem borer resistance were susceptible to stem borers and ear tip length had a significant relationship with stem borer infestation which indirectly affect the grain yield.