THE EFFECT OF PHOTOPERIOD INSENSITIVITY ON THE SALT TOLERANCE OF AMPHIPLOIDS BETWEEN BREAD WHEAT (TRITICUM-AESTIVUM) AND SAND COUCH GRASS (THINOPYRUM-BESSARABICUM)

The amphiploid between bread wheat cv. 'Chinese Spring' and sand couch grass Thinopyrum bessarabicum is tolerant of salinity stress under lo ng daylengths, but is extremely late-flowering and grows poorly under short daylength conditions. A newly synthesized amphiploid between the intervarietal single chromosome substitution line carrying chromosome 2D of the photoinsensitive cultivar 'Ciano 67' in a 'Chinese Spring' background and the same accession of Th. bessarabicum is photoinsensit ive and is more tolerant of salinity stress under short daylengths, bo th in terms of decreased ionic uptake and in showing less damage to a range of agronomic characters. The genetic basis of this difference is probably due to the presence in this genotype of both Ppd1 and to all elic differences between the Thinopyrum gametes involved in the two am phiploids.