Turnip

Brassica rapa var. rapa

Synonyms - Brassica rapa ssp. campestris. Brassica campestris.

Family: - Brassicaceae.

Names:

Brassica is the Latin name for cabbage.
Turnip.

Summary:

An erect annual or biennial plant, with bright yellow, 4 petalled flowers that form 20-50 mm long pods. It is normally 70 cm to 1.5 m tall with branching stems. The rosette leaves are usually deeply lobed and bright green rather than blue-green.

Description:

Cotyledons:

Two. The kidney shaped cotyledons are 5 to 8 mm long by 8 to 15 mm wide with a petiole 5 to 10 mm long, and are hairless. The seedling has a long hypocotyl but no epicotyl.

First leaves:

The leaves grow singly, the first being 30 to 55 mm long with a petiole 5 to 15 mm long.

Leaves:

Forms a basal rosette that may die off before seeds develop. The leaves are green rather than blue-green.
Stipules -
Petiole - yes.
Blade - 100-300 x 45-90 mm. The margin is lobed and from the second leaf on and these lobes are often completely separated towards the base of the leaf. Hairless or with scattered stiff hairs and cilia.
Stem leaves - The lower stem leaves are similar to the later rosette leaves with petioles. The upper stem leaves are sessile and clasping, up to 100 mm long, smooth and hairless.

Stems:

The stems are polygonal in cross section, solid with a pithy core, and hairless or have a few stiff hairs. Longitudinal striations are often present especially on later stems.

Flower head:

Elongates from a terminal, concave corymb of flowers

Flowers:

The flowers are approximately 15 mm in diameter.
Ovary - Sessile.
Sepals - Spreading. 4-7 mm long.
Petals - 4. Bright yellow. 6-14 mm long.
Stamens -
Anthers -

Fruit:

20-50 x 3-4 mm pod with 1-30 seeds. Somewhat flattened. Seedless, conical beak that is 5-12 mm long and narrower at the apex than the stigma.

Seeds:

1.5-2 mm. Spherical.

Roots:

Swollen tuberous taproot used as a vegetable.

Key Characters:

Swollen taproot

Biology:

Life cycle:

Annual or biennial. Seeds germinate in autumn and it forms a rosette in winter. In spring the flowering stem emerges and flowering occurs in late spring.

Reproduction:

By seed or re sprouting from rootstock.

Flowering times:

September to November.

Seed Biology and Germination:

Vegetative Propagules:

Re grows from taproot.

Hybrids:

Forms hybrids, which may make identification difficult.

Allelopathy:

Probably.

Population Dynamics and Dispersal:

Spread by seed.

Origin and History:

Europe.

Distribution:

ACT, NSW, NT, QLD, SA, TAS, VIC, WA.

Courtesy Australia's Virtual Herbarium.

Habitats:

Disturbed areas.

Climate:

Temperate.

Soil:

Well drained coastal soils.

Plant Associations:

Significance:

Beneficial:

Swollen taproot used as a vegetable. Oilseed. Honey plant. Fodder.

Detrimental:

Weed of crops, vegetables disturbed areas and roadsides.

Toxicity:

Cattle grazing frost affected turnips (Brassica rapa) in winter (June) have been poisoned.
It may also cause goitre in lambs and ewes fed tops and roots.

Symptoms:

Cattle and sheep. Foaming red urine, anaemia, light mouth membranes, weakness, dejection, jaundice, constipation.
Goitre.

Treatment:

Remove stock from source of turnip.

Legislation:

None.

Management and Control:

Thresholds:

Eradication strategies:

Most of the Brassicaceae weeds have dormant seeds that continue to germinate throughout the season and for several years. They often mature and set seed very quickly. Manual removal is effective but must be done at least every 8-10 weeks. Once pods are formed, seed will often mature even if the plant has been uprooted. Soil disturbance often leads to a flush of seedlings.
Many are somewhat unpalatable, so grazing only offers partial control. They often flourish in undergrazed, sunny areas.
In bushland situations, fairly selective control can be achieved with 100 mL spray oil plus 0.1 g Eclipse® or 0.5 g Logran® in 10 L water. 5 mL Brodal® is often added to this mix to provide residual control of seedlings. Spray the plants until just wet from the seedling stage up to pod formation.
Isolated plants should be removed manually and burnt if flowering or seeding and a 10 m buffer area sprayed with 10 mL Brodal® in 10 L water.
500 mL/ha of glyphosate(450g/L) can be used at flowering to reduce the seed set of most species on roadsides without causing significant damage to most native plants.
Wick application with 1 part glyphosate(450g/L) in 2 parts water or overall spraying with 100 mL glyphosate(450g/L) in 10 L water provides reasonable control of most species though Wild Radish tends to regrow.

Herbicide resistance:

None reported

Related plants:

Black Mustard (Brassica nigra)
Broccoli (Brassica oleracea var. italica)
Brussels Sprouts (Brassica oleracea var. gemmifera)
Cabbage (Brassica oleracea var. capitata)
Cauliflower (Brassica oleracea var. botrytis)
Chinese Cabbage (Brassica chinensis)
Indian Mustard (Brassica juncea)
Kale (Brassica oleracea var. acephala)
Kohlrabi (Brassica oleracea var. gongylodes)
Mediterranean Turnip (Brassica tournefortii)
Rape or Canola (Brassica napus var. napus)
Rapeseed (Brassica rapa var. sylvestris)
Savoy cabbage (Brassica oleracea var. sabauda)
Smooth Stemmed Turnip (Brassica oxyrrhina)
Swede (Brassica napus var. napobrassica)
Twiggy Turnip (Brassica fruticulosa)
Winter Rape (Brassica napus var.biennis)
Brassica elongata
The native Brassicaceae species usually have short, broad and smooth pods.

Plants of similar appearance:

A stout rather than swollen taproot distinguishes rapeseed (Brassica rapa var. sylvestris) from Wild Turnip (Brassica rapa ssp. campestris).

References:

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). P213.

Gardner, G.A. and Bennetts, H.W. (1956). The toxic plants of Western Australia. (West Australian Newspapers Ltd, Perth). P32.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne). p.

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #195.19.

Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P161.