Vernalization and photoperiodic responses of selected chromosome substitution lines derived from 'Rescue', 'Cadet', and 'Cypress' wheats

The vernalization responses of 'Rescue', 'Cadet', 'Cypress', and selected chromosome substitution lines derived from these cultivars were measured by comparing days to ear emergence of vernalized and unvernalized plants under 24- and 16-h photoperiods. The genotype of 'Cadet' appears to be Vrn1Vrni1, vrn4vrn4, vrnxvrnx (where vrnx is an unidentified locus), and of 'Rescue' vrn1vrn1, Vrn3Vrn3, Vrn4Vrn4. 'Cypress' appears to carry Vrn4 and one or both of vrn1, and vrn3. Although some minor photoperiod responses were observed, no loci involved in major photoperiod responses were detected on chromosomes 5A, 4B, and 5B in 'Rescue' or 'Cadet' or on chromosome 5B in 'Cypress'. However, the duration of the basic vegetative phase appears to be controlled by a locus or loci on chromosome 5B, and chromosomes 5A and 4B may be involved in minor photoperiodic responses.