Embryo-callus-regenerated hybrids and their colchicine-induced amphiploids between Elymus canadensis and Secale cereale

Abstract

Intergeneric hybrids recovered through plant regeneration from embryo callus culture and their colchicine-induced amphiploids were obtained from a cross of Elymus canadensis with Secale cereale (cv 'Gazeller'). The embryo-callus-regenerated F1 plants grew vigorously to maturity and regrew well after clipping, while the embryo-rescued F1 died of hybrid necrosis before maturity. Most of the morphological characters of the sterile F1 hybrids were intermediate between the parents, but tiller number and dry matter yield were higher than the parents. Amphiploids from these F1 plants had improved fertility but were less vigorous than the F1 plants. The predominance of univalents in the F1 and bivalents in the amphiploids indicated that the genomes S, H, and R were distinct. However, the occasional occurrence of multivalents reflected a random, intergenomic or intragenomic pairing. The mean chromosome associations of the F1 (2n=21, SHR), the C0 amphiploids (2n=42, SSHHRR), and the C1 amphiploid (2n=40) at metaphase I (MI) were 16.51I+2.05II+0.06III+0.02IV+0.02V, 2.20I+19.87II +0.02IV, and 7.10I+16.37II+0.04III+0.02IV, respectively. These amphiploids could be exploited as new germplasm for forage crop improvement by controlled introgression and backcrosses to the parents.