Summary. The seed banks of 6 subterranean clover
(Trifolium subterraneum L.) cultivars were sampled at 3
abandoned cultivar evaluation experiments in south-western Victoria (Hamilton,
Macarthur and Timboon). Two were var. yanninicum
(Trikkala and Larisa) and 4 were var. subterraneum
(Denmark, Goulburn, Karridale and Leura). Seed was sampled in late
summer–early autumn 1993, between 6 and 10 years after the sites were
established and between 3 and 7 years after the sites were abandoned. The
collected seed was separated into black and white seed, and a sample of the
black seed was grown in a glasshouse and identified as either belonging to the
sown cultivar or belonging to another cultivar/genotype. All white seed
was assumed to belong to the sown cultivar. The aim was to determine if these
widely used cultivars were persisting under farm management conditions and
competition from perennial grass, other subterranean clover and annual weeds.
With some variation between sites all cultivars were found to be persisting
satisfactorily. Over the 3 sites, white-seeded cultivars averaged 460
kg/ha and 6640 seeds/m2; black-seeded cultivars
averaged 260 kg/ha and 5590 seeds/m2.
Contamination with other subterranean clover cultivars/ecotypes was
generally low, except at Macarthur where the white-seeded cultivars were
heavily contaminated (Trikkala 39% pure; Larisa 57% pure) with
black seeds highlighting the poor adaptation of var.
yanninicum to light soil types. Of the black seeds, over
the 3 sites, average contamination level was 13% and ranged from
41% (Goulburn at Macarthur) to 1% (Leura at Timboon).
The study indicates that in south-western Victoria, all the recently released
cultivars are likely to persist and be productive, and that the small-plot
evaluation techniques used to identify potential new cultivars are likely to
be adequate if replicated in space and if the clovers are sown in mixed swards
with perennial grass.
Effect of annual weeds on the growth of perennial grass mixtures in the alpine region of the Qinghai‐Tibetan Plateau
