You-Zhi Li
Guangxi University, China
Title: Maize responses to photoperiod changes under controlled conditions
Biography
Biography: You-Zhi Li
Abstract
Response of maize to photoperiods affects adaption of this crop to environments. Sensitivity towards photoperiod changes has limited integration of tropical and temperate maize germplasm into existing breeding programs. We characterize the phenotypes of four temperate-adapted maize foundation parents, Huangzao 4, Chang 7-2, Ye 478 and Zheng 58 and two tropically-adapted maize foundation parents, M9 and Shuang M9 throughout the growth stage under three constant photoperiod regimes in a daily cycle of 24 h at 28º C and analyzed expression of 48 photoperiod response-associated genes. Consequently, long photoperiod (LP) repressed development of the tassels of photoperiod-sensitive maize lines at V9 stage and caused subsequent failure in flowering; Failure of photoperiod-sensitive maize lines in flowering under LP was associated with lower expression of flowering-related genes; Photoperiod changes could make a marked impact on spatial layout of maize inflorescence. The larger oscillation amplitude of expression of photoperiod-responsive genes occurred in LP-sensitive maize lines. In conclusion, failure in development of tassels at V9 stage under LP is an early indicator for judging photoperiod sensitivity. The adaptation of temperate-adapted maize lines to LP is due to the better coordination of expression among photoperiod-sensing genes instead of the loss of the genes. High photoperiod sensitivity of maize is due to high expression of circadian rhythm-responding genes improperly early in the light.