Simple Method for Overcoming the Lethality Observed in the Hybrid between Nicotiana suaveolens and N. tabacum

Abstract

Hybrid plants between N. suaveolens and N. tabacum plants exhibit lethality under standard culture conditions and die at the cotyledonary stage. For overcoming this type of high brid lethality, the effect of cytokinin was tested. The intact hybrid seedlings were cultured on media containing cytokinin (0-10mg/l kinetin or 6-benzylaminopurine (BAP)).Adventitious buds were regeneratcd from the base of the hypocotyl or the primary root of the dying seedlings. The regenerated shoots were transferred to the medium containing 2mg/l 3-indoleacetic acid (IAA) to accelerate rooting. The hybrid seedlings maintained a vigorous growth without developing any lethal symptoms up to maturity in a greenhouse. Forty chromosomes were counted in their somatic cells and their morphological characters were intermediate between those of parental species. Intact seedling culture with the addition of cytokinin was found to be a very simple method for overcoming lethality in this cross-combination.