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 potentiall y useful characters in T. tauschii and/or T. turgidum for genetic improveme nt of hexaploid wheat (T. aestivum). Synthetic hexaploid wheats and the T. turgidum and T. tauschii parents were assessed for their developmental resp onses to photoperiod and vernalization for days to ear emergence, final lea f number and the number of spikelets per spike. The responses to photoperio d and vernalization of the synthetic hexaploids were generally intermediate between those of the parents but in some instances the levels of expressio n 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 rath er the synthetic hexaploids reflected the photoperiod response of the respe ctive T. turgidum parents. The synthetic hexaploids had vernalization respo nses stronger than those of the T turgidum and bread wheats used in the stu dy. The expression of car emergence in response to vernalization of these s ynthetic hexaploids appeared to be modified by the T. turgidum parent. (C) 2001 Annals of Botany Company.