The Journal of Heredity 1984:75(4):273-276
© 1984 The American Genetic Association 75:273-276
research-article |
Possible mechanisms for the persistence of genes for shriveledseed trait in wheat strains derived from wheat-rye hybrids
Department of Agronomy, North Dakota State University Fargo, ND 58105
Abstract
The backcross progenies of wheat-rye (Secale cereale L.) hybrids produced common wheat (Triticum aestivum L.) plants having partial seed-set and two kinds of seed—shriveied and inviable; and plump and viable. In S2 to S7 progenies grown from plump seed, most plants had 21 pairs of normal wheat chromosomes during meiosis, apparently normal anthers and abundant pollen at anthesis, but reduced seed-set, and both plump and shriveied seed in their selfed and crossed spikes. In the reciprocal cross, spikes of control wheat plants pollinated with S2, S3, or S4 pollen had complete seed-set and plump seed, but the size and viability of some of the seed were reduced. The viable plump seed produced plants resembling S2, S3, or S4 male parents. It was concluded that plump and viable seed produced plants heterozygous for the alien genetic factor(s) controlling these traits and that the gametes and zygotes without the alien genetic factors had functional disadvantage and resulted in shriveled and reduced seed-set in the selfed and crossed spikes. The homozygosity for the alien genes was detrimental, and sporophytic effects controlled the inviability of some of the plump seed, especially those having embryos without the alien gene(s) from S3 or S4 plants used as male. An alternative explanation was that genetically instable plasmid-like factors may have been introduced from rye to wheat and abortion of gametes and zygotes without a certain number of these factors resulted in reduced seed-set, and inviable and shriveled seed.