A new tobacco cytoplasmic male sterile source from the hybrid combination Nicotiana longiflora Gav. and N. tabacum L. using in vitro techniques

Abstract

A new source of cytoplasmic male sterility (CMS) in tobacco that originated from an interspecific cross is reported. Hybrids of sexually incongruent species Nicotianalongiflora Gav. (n = 10) and N. tabacum L. (n = 24) were fully male and female sterile. The female sterility was overcome by inducing callus and organ formation from in vitro cultured stem pit parenchyma. The regenerants obtained after longer cultivation (six passages) had a chromosome number 2n = 4493 and restored female fertility. They were successfully pollinated with N. tabacum, forming seed-containing capsules. All BC₁P₂ plants were male sterile. They possessed normally developed corolla with shortened flower tube, strongly expressed longistily, filiform stamens with shortened filaments, and deformed anthers with 100% sterile pollen. This kind of male sterility was preserved in BC₂P₂BC₆P₂ progenies. Genetic analysis indicated maternal inheritance of the flower type, which confirmed its nuclearcytoplasmic nature due to interaction between nuclear genes of N. tabacum and cytoplasmic genes from N. long iflora.