Early heading mutants of T-monococcum and Ae. squarrosa, A- and D-genome ancestral species of hexaploid wheat

Two induced mutants for early heading in diploid species of Triticum monoco ccum and Aegilops squarrosa, A- and D-genome ancestral species common to co mmon wheat, were analyzed for the genetic behavior of the heading trait. Th e T. monococcum mutant headed earlier than its wild type under the long-day condition with vernalization treatment, whereas the Ae. squarrosa mutant h eaded under the short-day condition without any difference from the long-da y one. These results indicate that the former is a mutant for narrow-sense earliness, and the latter, for photoperiod sensitivity. Earliness of both m utants was found to be controlled by a recessive gene. These early-heading mutants could be useful sources for the breeding of heading earliness of co mmon wheat, as well as for genetic analysis for the determination of headin g time.