<p>Seed yield in perennial ryegrass is low and unpredictable. Breeding for a high stable seed yield is difficult, as seed yield is a complex trait with a low heritability. The aims of this study were to identify selection criteria for high seed yield and to gain more insight in the biology of seed reproduction in perennial ryegrass. Genotypic and temperature effects on pollen tube growth rate were detected. Cytological studies of seed development, ovule degeneration and seed abortion demonstrated that non-productive florets occurred at all positions within the ear. Abscission layer development and the mechanism of seed shattering were similar in genotypes with different seed retention.<p>Indirect selection for seed yield would be more efficient, if correlated traits with a high heritability could be identified, either in spaced plants or in crops grown in drilled plots. Significant and consistent differences for seed yield per plot were found among nine perennial ryegrass cultivars over three years at two locations. These differences were not correlated with thousand-grain weight, other seed yield components or crop physiological traits assessed in drilled plots. Spaced plants within each cultivar differed greatly for many traits. Broad-sense heritabilities were high for all spaced-plant traits, but narrow-sense heritabilities were only significant for some traits. No spaced-plant traits were identified that correlate with seed yield in drilled plots.
|Qualification||Doctor of Philosophy|
|Award date||2 Nov 1990|
|Place of Publication||S.l.|
|Publication status||Published - 1990|
- plant breeding
- seed treatment
- seed production