Genotypic Variation for Flowering in Maize Germplasm in the Rainforest Ecology of Sw Nigeria.

The number of days from planting to flowering in maize (Zea mays L.) is of interest to maize breeders because of its importance in the selection of appropriate hybrid parents and its role in the utilization of unadapted germplasm. Highly significant interaction of planting dates with varieties for flowering traits have been observed during the early and late cropping seasons in the rainforest agro-ecology of sw Nigeria. This makes the use of flowering dates as indicators of maturity unreliable. Therefore the objectives of this study were to evaluate 100 maize varieties forflowering traits and determine the climatic factors infuencing the interaction of the environments with days to flowering (GxE) in the rainforest ecology of sw Nigeria. One hundred maize varieties were evaluated during the late and early cropping seasons of 2007/2008 and 2008/2009. Significant differences were observed among the varieties for flowering traits (days to 50% tasseling, anthesis and silking). There were also significant year, season, season x year and variety x season interaction mean squares. In the early season, 97TZEE-Y-2C1 and TZEEPOPSTRCo, with 48-55 days to full flowering were the earliest to flower while Oba-Super II and ACR96DMR-LSR W with 64-71 days to flowering were the latest to flower. In the late seasons, 2004TZEE-WPOPSTRC4, TZEEPOPSTRCo, SINETEE-WSR and TZE-WPOPDTSTRC4F2 were the earliest to flower (42-47 days) while BUSOLA STR, TZLCOMPCO, 9021-18STR and Oba super II were the latest (61-68 days). Flowering interval was shorter in the late than the early season regardless of the maturity group. Temperature was the climatic factor primarily responsible for the number of days to flowering in this ecology.