Bitter Melon in Australia

FULL REPORT
This short report is a summary of a full report Bitter Melon in Australia (RIRDC Publication Number 02/134,UCQ-10a)by Professor David Midmore et al.who can be contacted on Phone 07 4930 9770, Fax:07 4930 9255,
Email:d.midmore@cqu.edu.au, Web:http://science.cqu.edu.au/psg/  
The full report is available in hardcopy for $15 from RIRDC (Phone:02/6272 4819) or can be downloaded for free from RIRDC ’s website: www.rirdc.gov.au/reports/Index.htm The report can also be purchased online from RIRDC ’s web shop:www.rirdc.gov.au/eshop  

Bitter melon (Momordica charantia L.) is frequently found growing in tropical and sub-tropical climates,and is consumed in most Asian countries.It is also produced in relatively smaller volumes in Australia, with winter production in the Northern Territory (NT ), Queensland and northern Western Australia and summer production steadily southwards to include New South Wales (NSW ) and Victoria (Vic).

A recent research project involved collabo- rative trials in growing bitter melon in the Northern Territory,Queensland and New South Wales.  The trials demonstrate that active cooperation and coordination rather than competitiveness in a particular industry can be an effective catalyst to improved production and marketing.

The research was headed by Professor David Midmore (Plant Sciences Group at Central Queensland University in Rockhampton)with participation from a range of other industry and research groups. The report was coordinated by Dr Wendy Morgan.

The work identified the bitter melon cul tivars Moon Light,Baizen and Long Type and the white fruit cultivar Moon Beauty as most suited for growing in Darwin.For northern NSW,Baizen and Moon Beauty gave the greatest yields. The report on the research says it is too soon for recommen- dations to be made for central Queens- land.

More agronomic research is needed, including better scheduling and nutrition and water management,particularly of

The Research

The research was funded from RIRDC’s Asian Foods R&D program,which aims to support industry to develop new products and markets and to gain competitive advantage through improving productivity.It seeks also to achieve premium prices for Australian production.

A series of replicated field and observation trials was undertaken in the Northern Territory, Queensland,and NSW from 1999 to 2001 to identify national production capability and supply, and productivity issues,for bitter melon.

In the Northern Territory,replicated field trials were undertaken at the Coastal Plains Horticultural Research Farm, 60 km south-east of Darwin.

Fruit there was harvested over five weeks.

Bitter melon cultivars yield parameters, Northern Territory, 2000 are shown in Table 1.

Observation trials were carried out at Burrin- gar on the North Coast of NSW with harvesting beginning in late January and extending through to mid-May.

Queensland’s observation trial involved hydroponic growing at the experimental grounds of the Central Queensland University’s Plant Sciences Group at Rockhampton.Harvest began in mid-May.

Fruit characteristics and water use of bitter melon cultivars grown hydroponically on two trellis types, Rockhampton, 2000 are shown in Table 2.

The Results

An essential market requirement for bitter melon is to harvest at the ‘mature green ’ development stage before the onset of ripening. This is important if the fruit is to be transported overland from origin to the market place which takes from one to five days. If any fruit has started the physiological process of ripening, they will produce ethylene and hasten the ripening of adjacent stored fruit.

Resulting yields from the trials of around 30 t/ha in the NT ,and 25-80 t/ha in northern NSW are in line with yields reported overseas. Hybrid varieties did not significantly out-yield open pollinated varieties, but tended to have more fruit set and lower individual fruit weight.

This inverse relationship was evident in Queensland too, but with the open pollinated variety with more fruit set. The height at which fruit set in NT may have been responsible for the recorded individual fruit weights of hybrids not reaching their claimed size.But effects of planting density may also have been involved in this anomaly.

Trellising to spread the canopy and to contain growth to primary and secondary branches is important for bitter melon production. A small trial at Rockhampton showed that overhead trellising was superior to vertical fence trellising as it made harvesting easier with fruit more visible, provided less fruit blemish and better fruit set and aeration for diminished disease outbreak.

 The Summary

Yield per plant was greater with the hybrids Baizen and Moon Beauty than the open polli- nated cultivar Long Type in New South Wales.

In Queensland when grown hydroponically, yield per plant was greater with Long Type than Baizen.In the Northern Territory, while the yield (total fruit weight per plot) was the same with the cultivars used, the fruit weight and number varied with each cultivar.

Those with lower average fruit weight had more fruit than the open pollinated local selection. The two hybrids also had a greater number of fruit per plant than the open pollinated local selection.

This would be expected as the local selection has been selected for site-specific performance over a number of years.Similarly, in Queensland, cultivars varied in fruit number and inversely in fruit weight.

Further work on agronomic practice for hybrid varieties may improve yield and fruit size.

Some work is also required to better define the time periods between flowering and harvest and extent of lateral shoot removal to suit condi- tions and cultivars.A practical indicator of main bulk harvest dates in research undertaken in the Philippines is 16-19 days after each peak female flowering.This varies with each cultivar.

 In Rockhampton it was approximately 18 days after peak female flowering,supporting the harvest indicator as a potentially useful tool for growers.

Knowing the number of flowers set weekly can also be used to predict expected total yield at any point. This could then be used in manage- ment decisions such as labour requirement and forward marketing.

Growers also place a great deal of importance on selecting for fruit size.In some trials a percentage of fruit matured on the vine before reaching a marketable size.This can be caused by poor pollination or early injury to fruit, but is also a varietal characteristic.

While the trials showed more work is needed on water management,nutrition and understanding the relationship between flowering and peak harvest,these trials give growers a basis to make more informed management decisions when growing bitter melon.