Possible mechanisms for the persistence of genes for shriveled-seed trait in wheat strains derived from wheat-rye hybrids

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-shriveled and inviable; and plump and viable. It was concluded that plump and viable seed produced plants heterozygous for the alien 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 S sub(3) or S sub(4) plants used as male.