| abstract |
The present invention provides a method for stably maintaining a genic male-sterile female parental line of bread wheat, durum wheat and triticale through selfing of the maintainer line. The male-sterile female line is used for the production of low-cost hybrid wheat or hybrid triticale seeds. It also provides a male-sterile female line homozygous for a recessive male-sterility allele, and a maintainer line which is readily and stably propagated. The maintainer line is isogenic to the female line but has an alien chromosomal arm, added to the wheat or triticale complement, carrying a dominant male-fertility allele that restores fertility to the maintainer line, heterologous microgametophytic- and macrogametophytic-suicide genes that kill pollen grains and embryo sacs carrying them thereby preventing the transmission of this chromosome arm to the progeny, a heterologous inducible anti macrogametophytic-suicide gene or anti microgametophytic-suicide gene and a heterologous selectable marker. Because of the activity of the microgametophyticÂand macrogametophytic-suicide genes all the progeny of the selfed maintainer are male-sterile female plants. When the activity of the anti macrogametophytic- or anti microgametophytic-suicide gene is induced, also female gametes or male gametes, respectively, carrying the alien chromosome arm are viable and since the frequency of these gametes is about 20%, the progeny of the selfed maintainer contains a mixture of female plants (80%) and maintainer plants (20%). The selectable marker facilitates the selection of maintainer plants among the progeny of the selfed maintainer line and thus, maintenance of the maintainer itself. The female lines and the hybrid lines do not contain heterologous genes and therefore, are not genetically modified organisms (GMO). |