Evaluation of biochemical and yield attributes of quality protein maize (Zea mays L.) in Nigeria

Twenty two genotypes of quality protein maize (QPM) and two local checks were assessed for their lysine and tryptophan levels, as well as grain yield characteristics at the Lower Niger River Basin Development Authority station, Oke-Oyi, Ilorin, Nigeria for three years (2009-2011). The results showed that the QPM genotypes and the standard checks varied from one another, with respect to crude protein, zein dry matter, zein crude, lysine and tryptophan. The best QPM hybrids for grain yield (Dada-ba, ART98-SW5-OB, ART98-SW4-OB and TZPB-OB had percentage lysine and tryptophan advantage of 34% compared with the local checks. These hybrids also out-yielded other genotypes with yield advantage of 10, 24 and 26% over the best inbred, open pollinated variety and the standard check respectively. However, grain yield showed positive association with all the characteristics except crude protein content. Kernel number per cob had maximum correlation with grain yield followed by kernel rows per cob, cob diameter and cob weight. The direct effect for crude protein was positive but the correlation was negative. Conclusively, the QPM hybrids that combined high yield with the essential amino acids could be tested in different savanna agro-ecologies to identify those that could be released to farmers, while the superior inbreds could be introgressed for further breeding programs. Keywords: Lysine, tryptophan, inbred lines, hybrids, open pollinated varietie