Two early-maturing maize (Zea maysL.} composites, TZE COMP 3 and TZE COMP 4, are undergoing improvement by reciprocal recurrent selection (RRS) at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria. Fifty random Si lines from each of the original (CO) and the two improved cycles (Cl and C2) of selection were evaluated at Ikenne in 1998 and 1999 and at Zaria in 1999. The objective was to determine the progress from two cycles of selection. Response to selection for grain yield was 10.4% per cycle in TZE COMP3 and 5.7% in TZE COMP4. Selection also increased days to 50% silking, ear height, and plant height by 1.18 to 3.76% per cycle, but reduced plant and ear aspects.

Plant Genetic Resources; Maize

Maize; Genetic Variance