THE CHROMOSOME CONSTITUTION OF HEXAPLOID WINTER TRITICALES

Abstract
Eighty-three advanced winter triticales (.times. Triticosecale Wittmack) derived from various initial crosses and 7 unselected triticale .times. bread wheat (Triticum aestivum L.) F5 lines were screened for the presence of rye chromosomes. Seventy-six advanced lines had 7 pairs of rye (Secale cereale L.) chromosomes, suggesting selection pressure favoring retention of the complete rye genome. The results for unselected lines suggest the operation of natural disruptive selection for parental types. Possible factors involved in yielding different chromosome constitutions in winter and spring triticales are discussed.