GENETIC CENTRAL OF ANDROGENETIC RESPONSE IN LOLIUM-PERENNE L

In a study of androgenesis in 90 Norwegian genotypes of perennial ryeg rass (Lolium perenne L.), heritabilities ranged from h(b)(2) = 0.46 to 0.80. Very high or completely positive genotypic correlations were fo und between most characters of androgenetic response (e.g. embryo-like structures per 100 anthers, plants per 100 embryo-like structures, al bino plants per 100 anthers, green plants per 100 anthers). Three geno types, 2 Norwegian (7-5 and 9-5) and 1 Danish (245), which had signifi cantly different androgenetic responses were selected to study the gen etic control of the processes. Genotypes 7-5 and 9-5 were highly embry ogenic, 7-5 and 245 were relatively high producers of green plants, wh ile 9-5 was unable to produce green plants. The six possible reciproca l crosses between these three genotypes were made, and 10 or 11 F-1 pl ants from each cross were used for anther culture experiments. The cro ss 7-5x245 showed average superiority over both parents for total plan t regeneration and green plant production, results not previously repo rted. The phenotypic correlations estimated among progenies from the c rosses ranged from r=-0.99** to 0.81***. These considerable changes, relative to the results of the screening experiment, are most likely t he result of changed allele frequencies caused by the strong selection of parents in these crosses, and a relatively simple genetical contro l. This is also inferred from the large transgressive segregation obse rved.