SELF-FERTILE DOUBLED HAPLOID PLANTS OF PERENNIAL RYEGRASS (LOLIUM-PERENNE L)

The self-fertility of chromosome-doubled haploid lines of perennial ry egrass and their first (I1) and second (I2) generation selfed offsprin g was studied. The overall seed set was low, 0-0.4 seeds per spike, as would be expected for chromosome-doubled haploids of a self-incompati ble species. Nevertheless, significant genetic variation was observed for self-fertility within three of the six lines studied. Within one l ine, three 12-clones showed increased self-fertility, while in two oth er lines one and three I1-clones, respectively, showed significantly i ncreased self-fertility. Selection, during selfing, of rare pollen gra ins with mutations in the self-incompatibility system could explain th e observed changes and would lead to a general breakdown of self-incom patibility in Lolium perenne during repeated selfing of chromosome-dou bled haploids.