Chinese chard

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Chinese Chard Links

• Purdue University, Indiana 
• Multilingual multiscript plant name database 
• Plants for a Future - UK

Species: Brassica rapa L. cv. group Pak Choi

Family: Cruciferae

Crop status: New

Varieties

There is a wide range of cultivars available. Four major groups can be identified, based on appearance (see Moore et al. 1998, and photos in the Access to Asia links above). See Seedquest for a list of seed companies.

Agronomic trials

Agriculture Victoria is conducting trials in 1999, following on from previous years. Observational work has been done at University of Queensland Gatton campus (Alan Wearing 1998, pers. comm.).

Production

Chinese chard is produced mainly by Chinese and Vietnamese Australians, and partly by traditional brassica growers who wish to diversify. It requires the same equipment, but Chinese chard grows faster and probably requires more labour than other brassicas (Moore et al. 1998). It is grown commercially in all states of Australia (Lee 1995).

Season: Cool season crop, preferring moist and uniform conditions in full sunlight. It has been grown successfully in all Australian states (Moore et al. 1998) and can be grown year round at Gosford (Nguyen 1992), WA (Hill 1988) and in Victoria. Change from cold season (Chinese White and soup spoon) varieties to heat tolerant (Shanghai and Canton) varieties as season permits (Moore et al. 1998). Growth is best in Spring and Autumn.

Temperature: Preferably 15-20ºC, but heat tolerant varieties are also available. A diurnal temperature variation of about 5-6ºC is preferred. High temperatures with long days will induce bolting. Fairly frost tolerant, particularly the Shanghai Chinese Chard. The Chinese White Bok Choy has a tendency to bolt (Moore et al. 1998).

Soil type: Prefers rich loamy soils with high fertility, organic matter and water retention (Moore et al. 1998).

Soil preparation: Raised beds with good drainage and air circulation will help prevent the incidence of soft rots (Moore et al. 1998).

Wind: Shelter from wind is important, particularly for young plants (Moore et al. 1998).

pH: 6.5 to 7.0. Add lime if pH falls below 6.0. This may also reduce clubroot incidence (Moore et al. 1998).

Plant density: Within row spacing varies from 2.5 to 10 cm for the smallest varieties, up to 45 cm for the largest. Spacing between rows varies around 18 - 30 cm (Moore et al. 1998).

Germination: 5-10 days after sowing.

Transplanting: Can be sown directly or transplanted, but transplanting can reduce growing period and chance of bolting in adverse conditions (Moore et al. 1998). Also, seeds are very small and difficult to handle when sowing directly (Hugh Allan in Daley 1998). Germinate and raise at 18 - 20ºC, and then drop to 10ºC soon before transplanting to reduce the shock of going into the field. Transplant after about 25 - 30 days of growth (Moore et al. 1998).

Housing: Green or polyhouses enable year round production and more control over wind and temperature. Keep temperature at 20ºC if possible (Moore et al. 1998).

Nutrition: High levels of nitrogen (400 kg/ha) may increase incidence of soft rot (Moore et al. 1998).

Water: It is a shallow rooted crop, thus it requires frequent watering to optimise growth, quality, and reduce the incidence of bolting. Apply lightly to avoid leaching (Moore et al. 1998).

Harvest: 35 - 55 days after sowing, before the plant is fully mature as it becomes fibrous, and may bolt. Certainly harvest if there is any evidence of bolting, and well before the outer leaves begin turning yellow. Use a knife to cut by hand at the base, remove dead and damaged leaves and trim the base to flush with the first petiole. Harvest in the cool part of the day (Moore et al. 1998).

Yield: Average about 15 t/ha (Moore et al. 1998).

Dr Trish Grant has recently been employed to study preharvest influences on Chinese chard and Chinese cabbage at AgVic, Knoxfield.

Postharvest

Handling: Prone to physical damage, mainly bruising of the petiole. Australian producers bunch into groups of 2-3 plants using string, which tends to bruise the plants (Moore et al. 1998).

Temperature: Best at 0-1ºC (Moore et al. 1998) but should not be allowed to freeze (Thomson 1999).

Relative humidity: 85 - 100%. The plant is susceptible to wilting (Moore et al. 1998).

Shelf life: Pak choy varieties store for a week, bok choy varieties a bit longer. Both should be used as fresh as possible (Moore et al. 1998). At 10ºC and the appropriate modified atmosphere packaging (MAP), it is possible to achieve a shelf life of 19 days for pak choy (O'Hare et al. 1998). Lower temperatures and MAP can result in a shelf life up to a month (Moore et al. 1998).

Modified Atmospheric Packaging: Leaves and shoots are quite different for packaging, since leaves respire at 1.8 times the rate of shoots. Hence, packaging for salad mix is different than for the entire plant. Research at QDPI Hamilton will concentrate on substrate reserve, ethylene metabolism and the relationship with other plant growth regulators, and how these relate to storage temperature. Team includes Tim O'Hare, John Bagshaw, Amanda Able and Lung Wong.

Pests and diseases

Potential viruses are listed at Plant viruses online (Brunt et al. 1996).

Aphids and green looper caterpillars are the common pests (Nguyen 1992).

Erwinia carotovora causes a mushy decay of leaf petioles nearest the ground. It is commonly found in decaying vegetable matter as it infects wounds, and it thrives in hot weather (Nguyen 1992).

Albugo candida (white rust) causes a mass of small white, circular raised spots on both sides of the leaf, and is common in cool, wet weather (Nguyen 1992).

Pseudocerosporella capsellae causes spots on the leaves (Chew and Morgan 1997).

Rhizoctonia causes mould on the stems (Chew and Morgan 1997).

Plasmodiophora brassicae (clubroot) incidence and severity may be reduced with the application of lime (Moore et al. 1998).

Clubroot, downy mildew, white rust, aphids, caterpillars and snails/slugs are all described in Moore et al. (1998).

(A)

(B)

Figure 1: High and low prices of Chinese chard (A) and Baby Chinese Chard (B) at Flemington Markets during 1996 (green), 1997 (blue) and the first half of 1998 (red), recorded on a half monthly basis. Note that the weight of one dozen cuttings can vary with season (Flemington Market Reporting Service, NSW Agriculture).

Domestic market

Development potential was rated as high for the fresh domestic market (Vinning 1995, Lee 1996). It is the most important Asian vegetable after Chinese cabbage (Moore et al. 1998).

Melbourne and Sydney wholesale prices averaged between $0.50 and $3.00 per bunch, and retail price in Melbourne was about $3.00 per bunch (Moore et al. 1998). Melbourne is supplied from both Victoria and New South Wales (Chew and Morgan 1996).

Export market

(click here for exchange rates).

Used throughout Asia as an integral part of most meals, hence there will always be a market. Consumed boiled, sauteed, steamed, braised and stir-fried as a soup, side dish, or part of the main dish (Vinning 1995).

Not viable for export from WA because it is a low density product, hence is a high cost/kg to export, and its value in Asian countries is low.

Tokyo annual wholesale price (340 ¥/kg) and volume (6500 t) are increasing. Highest prices occur in January and February when production is lowest (Vinning 1995).

One of the top five vegetables sold in Indonesia (Lee 1996).

Figure 2: Throughput of bok choy at Flemington Markets during 1996 (green), 1997 (blue) and the first half of 1998 (red), recorded on a monthly basis. Note that the weight of one dozen cuttings can vary with season (Flemington Market Reporting Service, NSW Agriculture).

Related projects

Tim O'Hare (Sept 1996 - Sept 1998). Extending shelf life of minimally processed Asian vegetables. RIRDC Project Number DAQ-213A.

Tim O'Hare (1 July 1998 - 31 June 2001). Extending the shelf life of leafy vegetables. ACIAR Project Number 9416. (Chinese chard is used as the model crop for this project).

References

Brunt, A.A., Crabtree, K., Dallwitz, M.J., Gibbs, A.J., Watson, L. and Zurcher, E.J. (eds.) (1996 onwards). `Plant Viruses Online: Descriptions and Lists from the VIDE Database. Version: 16th January 1997.'

Chew, M. and W. Morgan (1996). Melbourne retail Asian vegetable survey. Melbourne, Agriculture Victoria 143 pp.

Chew, M. and W. Morgan. (1997). List of identified pests and diseases affecting Asian vegetables. Access to Asian Vegetables. (2): 1.

Daley, P. (1998). Giant radish shows promise. The Land (26 Feb): 8.

Hill, T. (1988). Recommended cultivars of Chinese vegetables. Department of Agriculture Western Australia Farmnote No. 112/88.

Lee, B. (1995). Audit of the Australian Asian vegetables industry. RIRDC Research Paper No. 95/13. Canberra, Rural Industries Research and Development Corporation 97 pp.

Lee , B. (1996). Assessment of economic benefits for Asian vegetables. RIRDC project CON-4A review meeting 14 November 1996.

Moore, S., W. Morgan and M. Chew. (1998). Chinese chard. The New Rural Industries. Ed.: K. W. Hyde. Canberra, Rural Industries Research and Development Corporation, pp. 172-177.

Nguyen, V. Q. (1992). Growing Asian vegetables. Agfact, NSW Agriculture H8.1.37.

O'Hare, T. J., L. S. Wong, et al. (1998). Extending the Shelflife of Leafy Asian Vegetables. RIRDC Publication No 98/? Canberra, Rural Industries Research and Development Corporation pp.

Thomson, G. (1999). Postharvest handling of leafy Asian vegetables. Access to Asian Vegetables. (16): 1.

Vinning, G. (1995). Market Compendium of Asian Vegetables. RIRDC Research Paper No. 95/12. Canberra, Rural Industries Research and Development Corporation 386 pp