Inheritance Patterns of the Response to in vitro Doubled Haploid Induction in Perennial Ryegrass (Lolium perenne L.)

Hybrid breeding significantly contributed to the yield increases of many important crop species. In a self-incompatible outbreeder like perennial ryegrass (Lolium perenne L.), doubled haploid (DH) production through androgenesis may well be the most practical method to obtain homozygous lines for hybrid breeding. Through in vitro anther culture, completely homozygous material can be produced in a single generation. Currently however, most breeding germplasm is recalcitrant to such procedures, necessitating the introgression of androgenic capacity. Our aim is to uncover genetic factors important for DH induction, by studying populations segregating for the response to anther culture. Here, we present phenotypic results obtained during two years of DH induction as well as some preliminary data on the behavior of DHs in the field. Widely different responses were observed within and between populations, although genotypes producing a high number of green DHs could be identified in the offspring of each pair cross. A clear effect of different parental combinations, as well as the distribution of the responses for each evaluated trait, indicates that a distinct number of loci control embryo induction and green plant regeneration. Ultimately, through the analysis of phenotypic observations and genotyping data by family-based association mapping, genetic loci and marker-trait associations will be identified. A marker-based breeding tool can thus be developed, which will aid the screening of germplasm for DH induction ability and its introgression into elite material. This work will contribute significantly to the development of hybrid breeding strategies in perennial ryegrass.