Rice

Oryza sativa L.

Order: Poales

Family: Poaceae

Names:

Oryza
Sativa is Latin for sown or planted referring to it as the cultivated form.
Rice

Other Names

Summary:

A tropical, annual cereal to 40 cm tall with light grain in a open seed head with few branches.

Description:

Cotyledons:

One.

Leaves:

Blade -
Ligule -
Auricles -
Sheath -

Stems:

Up to 400 mm tall.
Flower stem -

Flower head:

Panicle with a few branches, initially erect then nodding and turning golden brown as the grain fills

Flowers:

Spikelets -
Florets -
Glumes -
Palea -
Lemma -
Stamens -
Anthers -

Seeds:

Oval grain.

Roots:

Fibrous.

Key Characters:

Biology:

Life cycle:

Annual.
In NSW, seed is planted in September to October, intermittently flooded until seedlings have established then flooded until harvest. For aerial sowing, seed is pre germinated and sown into wet fields. Grain is harvested from March to May.
In Queensland, the dry season crop is sown in June to July and harvested in December to January. The wet season crop is sown in December to January and harvested in April to May.
After grain is harvested it is milled to remove the hulls and this yields brown rice. The high oil content of the germ limits the storage of brown rice so the outer coat is remove to yield white rice which is then polished. Whole grain and several grades of broken gain are sold.

Physiology:

Reproduction:

By seed.

Flowering times:

Summer in WA.

Seed Biology and Germination:

Vegetative Propagules:

Hybrids:

Many commercial varieties. Var. indica has long hard grain and grown in tropical areas. Var. japonica has short, soft grain, grown in more temperate areas with higher yields and used for cooking. Many new varieties cross this classification.

Population Dynamics and Dispersal:

Spread mainly by intentional planting.

Origin and History:

India. Indo China.
Introduced as a cereal crop. First cultivated commercially in NSW in 1924-5.

Distribution:

QLD, NSW, NT, WA.
Naturalised in WA along the lower Ord River.

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Sub tropical. Tropical.
Usually grown between 490N and 350S in warm areas with abundant water.

Soil:

Plant Associations:

Significance:

Beneficial:

Important cereal food crop. Milled rice used for human consumption, cracked rice for starch, edible rice oil is extracted from the bran and by products used for stock feed. Hulls often burnt to provide energy for drying and the ash is used ash an absorbent.

Detrimental:

Toxicity:

Not recorded as toxic.

Legislation:

None.

Management and Control:

Thresholds:

Eradication strategies:

Herbicide resistance:

Biological Control:

Related plants:

Australian Rice (Oryza australiensis)
Australian Wild Rice (Oryza meridionalis)
Red Rice (Oryza rufipogon)

Plants of similar appearance:

References:

Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P60.

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). 912.4.

Reid, R.L. (1990) The Manual of Australian Agriculture. (Butterworths, Sydney). P83-86. Diagram.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.