Photoperiod and vernalization responses in Triticum turgidum x T-tauschii synthetic hexaploid wheats

Studies of synthetic hexaploid wheat developed from Triticum turgidum (AABB genomes) and T. tauschii (DD genome) can provide information on potentially useful characters in T. tauschii and/or T. turgidum for genetic improvement of hexaploid wheat (T. aestivum). Synthetic hexaploid wheats and the T. turgidum and T. tauschii parents were assessed for their developmental responses to photoperiod and vernalization for days to ear emergence, final leaf number and the number of spikelets per spike. The responses to photoperiod and vernalization of the synthetic hexaploids were generally intermediate between those of the parents but in some instances the levels of expression exhibited by the T. tauschii or T. turgidum parents were epistatic in the synthetic hexaploids. The relatively strong photoperiod response of the T tauschii accessions was not expressed in the synthetic hexaploids, but rather the synthetic hexaploids reflected the photoperiod response of the respective T. turgidum parents. The synthetic hexaploids had vernalization responses stronger than those of the T turgidum and bread wheats used in the study. The expression of car emergence in response to vernalization of these synthetic hexaploids appeared to be modified by the T. turgidum parent. (C) 2001 Annals of Botany Company.