Trend in the Performance of Five Open Pollinated Maize Varieties ( Zea mays L.) for Grain Yield in different Planting Dates and Years in the Southern Guinea Savanna Ecology of Nigeria

Three drought tolerant and two adapted maize varieties were evaluated at the University of Ilorin Teaching and Research farm in 2002 and 2003 cropping seasons, using monthly plantings between April and August of each year. Year (Y) and planting time (PD) had significant effects on all traits except anthesis-silking interval. Genotypic differences were significant for all the characters except seedling emergence. Effects of Y x PD, G x Y and G x PD interaction were significant for all parameters except ASI. 2003 cropping season was better than 2002 for the expression of grain yield potentials in the varieties cropping seasons. Early plantings resulted in higher grain yields than late. DT-SR-WCO and DT-SR-Y CO that are superior for grain yield can be tested further under farmers’ growing conditions or utilized in the extraction of inbred lines for the development of improved maize varieties for cultivation in the savanna ecologies of Nigeria. Key words: Drought tolerant, Maize varieties