Plant Genomics

Biography

Biography: You-Zhi Li

Abstract

Response of maize to      photoperiods      affects adaption of this     crop     to environments. Sensitivity tow ards     photoperiod     changes has limited integration of tropica l 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 gr owth 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 line s at V9 stage and caused subsequent failure in flowe ring; Failure of  photoperiod -sensitive maize lines in flowering under LP was associated with lower expr ession 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 sensitivi ty  . The adaptation o f  temperate-adapted maize  l i nes 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.