Two field experiments were conducted to identify CIMMYTMaize Lines (CMLs) and their hybrid combinations with the least susceptibility to pink stem borer under artificial infestation in the field. The first trial comprised of 28 inbred lines with two resistant checks, Winpink 4 (resistant control 1), CM 500 (resistant control 2), and one susceptible control, CM 300. The second trial was comprised of 45 yellow single crosses and Winpink 5 (resistant control 1), CM 500 (resistant control 2) and CM 300 (susceptible control). The lines and crosses were separated into four categories on the basis of the leaf injury rating (LIR): (i) Highly resistant: LIR less than the resistant controls; (ii) Moderately resistant: LIR more than resistant control 2 and less than 5.0; (iii) Susceptible: LIR above 5.0 and less than the susceptible control, CM 300; and (iv) Highly susceptible: LIR above the susceptible control. Of the 28 lines screened, 4 were found to be moderately resistant. CML 421 recorded an of 4.4, which was followed by CA03141 (4.60), CA03120 (4.60) and CA00106 (4.75). The crosses CML 429 were found to be highly resistant. As many as 38 crosses were found to be moderately resistant, recording an LIR of less than 5.0. Three crosses CML 427 were susceptible, recording an LIR less than the susceptible control CM 300 (6.20). Overall, the screening trials indicated that the inbred lines CML 421, CA0 3141, CA00106 and CA03120 and single crosses CML.

Text in English