Het beoordelen van planten en families bij de veredeling van Phleum pratense

Progeny testing of timothy was studied. Testing in mixture was carried out in two ways: drilling progenies in rows alternating with close (15 cm) lines of a competitive species and as spaced plants in the sward of a competitor (mostly perennial ryegrass). A positive but not always high correlation was found between testing in mixture and in monoculture. It was concluded that grasses should be tested in a dense crop, as the order of the families is largely governed by competitive or non-competitive spacing. Interspecific competition will have an influence under unfavourable conditions. Root competition was more important than shoot competition. For dry matter yield and heading date, the effect of general combining ability was the most important part of genetic variance. The estimated heritability for dry matter yield was higher for testing in competition than in monoculture. The implications for breeding are discussed.