The impact of temperature on leaf appearance in bambara groundnut landraces

Ten bambara groundnut [Vigna subterranea (L.) Verde] landraces of diverse origin were used to examine the effect of temperature on the rate of leaf appearance (RLA) and to determine the base temperature (T-b) among landraces. Knowledge of leaf development is required in breeding programs where crop morphological development is considered an important selection criterion. The ability to predict leaf appearance would also facilitate modeling of plant development. Plants were grown in controlled-environment growth rooms under different temperatures (20, 25, 30, 32, and 35degreesC +/- 1). The study to examine the effect of temperature on leaf appearance in bambara groundnut landraces indicated that the base temperature (T-b) for leaf appearance ranged from 8.1 to 12.0degreesC. Within the range of temperatures evaluated in this study, the observation of differences in T-b values among the landraces suggests that Tb values for leaf appearance are landrace dependent. The phyllochron was also variable among landraces ranging from 40.9 to 53.0degreesC. The RLA ranged from 0.19 to 0.63 leaves d(-1) depending on temperature and landrace. The landrace variations in relation to leaf appearance may allow selection of landraces for different environments.