Prima gland clover

Origin

Prima was developed from an ecotype (ref. NYT2447) collected by J. S. Katznelson in 1976 in the Yehudiyya Forest, Golan, Israel. It was donated to the Australian Trifolium Genetic Resource Centre (ATGRC) and grown for characterisation and seed multiplication in 1993 under the Commonwealth Plant Introduction Code. It was selected for further evaluation in a Grains Research and Development Corporation funded project and it has been under national field evaluation by NAPLIP (National Annual Pasture Legume Improvement Program) since 1997.

Prima gland clover flowers

Description and area of use

Prima gland clover is an aerial seeding, self-regenerating annual pasture legume. It has hairless, waxy leaflets that are rounded in the rosette stage and become elongated as stems develop. The stems are slender and can reach 30-40cm in height when ungrazed. Flowering generally begins in mid September or between 100 and 110 days after sowing in Perth. The flowers are a distinctive light to dark pink colour and form into a globular head. Each floret will contain 2-3 small, yellow, oval shaped seeds of around 0.7mg. The hardseed level is high at senescence and will drop rapidly over late autumn to around 40-50% in mid winter. Prima has a high level of tolerance to redlegged earthmite (Halotydeus destructor), moderate tolerance to aphids and is susceptible to lucerne flea. Prima is not susceptible to clover scorch.

The maturity and hardseed dynamics of Prima are ideally suited to mediteranean climates with above 350mm of annual rainfall. It will grow on a range of soil pH (4.5- 8.0 in CaCl₂) and textures except poor infertile sands and can tolerate mild waterlogging. Seed crops however should target fertile sandy loams to clay loams with mildly acid to neutral pH. The hardseed level and breakdown will suit either crop:pasture rotations or longer term ‘phase’ type pastures between continuous cropping sequences. Prima is ideal for including in pasture mixtures to provide a backup pasture legume in situations of false break and heavy redlegged earthmite populations. The ease of seed production will allow on farm bulkup and therefore a more affordable large scale adoption.

Studies into the biochemical nature of the insect tolerance in Prima gland clover suggest it is based on a moderate level of the chemical coumarin. The presence of coumarin-containing species in fodder is of concern to animal health when spoilage occurs during haymaking. Fungal activity during spoilage can convert coumarin to dicoumarol, a vitamin K analogue, and in sufficient dosage and exposure can result in haemorrhage. The risk of this occurring with Prima gland clover is considered low due to:

• The relatively low coumarin level compared to the Melilotus spp. that are associated with the problem in north America.
• Artificial spoilage of pure Prima gland clover resulted in nil or low levels of measured dicoumarol.
• Sheep grazing dry Prima residue did not show any difference in blood clotting compared to a control group. During this grazing period the stubble was moist for several days after a significant summer rainfall event.

To further minimise this risk it is recommended that hay should not be cut from pastures containing a high level of gland clover. If hay does contain gland clover and spoilage occurs this should not be feed to any type or class of stock.