八倍體 elymus 屬植物과 四倍體 호밀間의 異質六倍體 雜種

Allohexaploid hybrids between octoploid elymus species and tetraploid secale cereale

In a breeding program to produce a new forage species with disease resistance and high yield, Elymus species, octoploid plants of Canada wild rye and Slender wheatgrass, were crossed with tetraploid Secale cereale cv. Duruhomil. Cross rate was 35.7% in a cross between octoploid Canada wild rye and tetraploid Duruhomil. In an embryo culture, six embryos from the cross were germinated but showed hybrid necrosis. Through callus induction and plant regeneration from ungerminated embryos, total five plants were obtained and, among these, three survived and grew to maturity. Cross rate was 20% in a cross between octoploid Slender wheatgrass and tetraploid Duruhomil. However, none of them survived even in an embryo culture. At the first metaphase of meiosis, octoploid Elymus plants showed chromosome configurations of seventeen to nineteen bivalents per cell on the average, and Duruhomil showed configuration of ten bivalent, one univalent, and one trivalent chromosomes per cell on the average, respectively. Allohexaploid hybrids were intermediate of the parents in morphological characteristics and showed chromosome configuration of twenty bivalents and two univalents per cell on the average. Pollen fertility of octoploid Canada wild rye and Duruhomil was 52.3% and 56.7%, respectively, and seed fertility of both plants was 18% and 75%, respectively. Pollen and seed fertility of allohexaploid was 25.1% and 2.5%, respectively.