Induced mutations in Triticum aegilopoides, Aegilops ventricosa and their synthetic allopolyploid

Abstract

Seeds of the diploid, Triticum aegilopoides (2n = 2x= 14 = AA), the tetraploid, Aegilops ventricosa (2n = 4x = 28 = MvMvDD) and their synthetic hexaploid (2n = 6x = 42 = AADD MvMv) were treated with gamma rays (16 kR) and with 1% aqueous solution of ethyl methanesulphonate (EMS) for 1 1/2 hours and 3 hours. In the diploid no mutation was observed probably owing to the low number of M2 seedlings derived from gamma rays treatment. The gamma rays seemed to produce more mutations than EMS in the tetraploid. In the hexaploid, the gamma rays and EMS seemed equally effective in producing mutations. At all levels of ploidy, EMS treatment for 3 hours induced more mutations than the EMS treatment for 1 1/2 hours. The present results confirm earlier results obtained from studies of induced mutations in natural polyploids and their putative parents. The induced chlorophyll mutations decreased with increasing number of homoeologous genomes. The buffering of the genic system behind the chlorophyll apparatus in the synthetic amphiploid was comparable with the situation in natural amphiploids. The synthetic amphiploid provides an additional example of homoeoallelism. The evolutionary significance and the possible roles of induced recessive mutations in improving the wild characters of Triticum aegilopoides, Aegilops ventricosa and of their synthetic amphiploid are discussed with reference to the incorporation of useful genetic variations into the cultivated wheats.