Marker-assisted breeding of onion (A. cepa L.) maintainer line resistant to downy mildew

Relevance. F1 hybrids breeding programs of onion are based on the use of nuclear cytoplasmic male sterility (NCMS). Breeding and seed production based on NCMS suggest a development of a female sterile maternal line, a maintainer line and a paternal component. The development of an isogenic pair of sterile line - maintainer line is one of the most labor-, time-consuming and intellectually-intensive stages of a breeding program, the implementation of which becomes more complicated with an increase in the number of traits / genes for which selection is carried out. Methods and results. This paper presents a genetic scheme for the development of a Downy mildew-resistant (pathogen P. destructor) maintainer line of onion using marker-assisted selection (MAS). F2 populations were obtained from the cross of the female maintainer inbred line, Bn1- (13) (genotype -cytN msms pdpd) and male inbred line resistant to Downy mildew, No. 136 (genotype - cytT MsMs PdPd). DNA marker DMR1 were used for Downy mildew resistance gene Pd, jnurf13 - for maintainer gene ms and marker system 5cob: orfA501 - for N, S and T cytoplasms. It was shown that the MAS application allow to develop a stable Downy mildew resistant maintainer line cytN msms PdPd in two generations.