Abstract

Field trials were conducted in 2006, 2007 and 2008 wet seasons, at the Institute for Agricultural Research Farm, Samaru in the Northern Guinea savanna of Nigeria to determine the individual and combined contributions (%) of some growth and yield parameters to yield of quality protein maize (Zea mays L.) varieties. Treatments consisted of four rates each of nitrogen (0, 60,120 and 180 kg N/ha) and sulfur fertilizer (0, 5, 10 and 15 kg S/ha) and two QPM varieties (Obatampa and EV-99), laid out in a split-plot design with variety and nitrogen in the main plots and sulfur in the sub plots and replicated three times. The results showed that among the growth parameters measured total dry matter and number of leaves/plant had the highest individual and combined contributions. However, when the individual and combined contributions of the yield components were studied, cob weight/ha, days to 50% tasselling and silking were observed to be the highest contributors to grain yield of quality protein maize.