POTENTIAL FOR CRAMBE (C. abyssinica)

IN MALLEE / WIMMERA OF AUSTRALIA

Geoffrey Castleman¹ Sally Pymer² and Claire Greenwood^2.

¹DNRE, Agriculture Victoria, Mallee Research Station, Walpeup, Vic. 3507

²DNRE, Agriculture Victoria, Victorian Institute for Dryland Agriculture, Horsham, Vic. 3500

KEYWORDS: Oilseed, oil, erucic acid, industrial, speciality

Abstract

In Australia there is increasing interest in speciality oils for industrial application.  Crambe was therefore evaluated in north - west Victoria, Australia, between 1992 and 1996.  It was envisaged that the plant species would grow satisfactorily and provide sufficient grain to be economically viable.  The species has the potential to provide the local farming community with an alternative oilseed crop to canola and the potential to provide industry with a new raw feedstock source.  Crambe was evaluated at two diverse environments to ascertain the yield potential of the species in low rainfall (Mallee, <350mm) and medium rainfall (Wimmera, 350 to 500mm) environments.  In eight trials, the species failed to yield on three occasions for different reasons in different environments (once in the Mallee and twice in the Wimmera).  Grain yields varied from < 100 to 2470kg/ha.  Crambe abyssinica produced higher grain yields in the low rainfall environments during the period of evaluation.  The trials indicated that under favourable growing conditions with varieties having wide adaptation, it might be possible in the future to exploit the species as an alternative source of industrial erucic acid to rapeseed (B. napus).  Varieties used in this series of experiments were source mostly from the U.S.A.  As an indication to seed oil content, 25 samples grown in 1996 were analysed. Their seed oil content varied from 35.57 to 42.81%.

Introduction

Crambe (KRAM-bee), Crambe. abyssinica (Hochst) is a member of the crucifer family, that includes annuals which originate mostly from the Mediterranean region and from Ethiopia to Tanzania, (Weiss, 1983).  The substantially branched plant usually grows to less than one metre in height.  Long racemes bear white flowers that produce single greenish-brown seeds encapsulated in white to fawn coloured capsules.

Interest in speciality oils for industrial application is increasing in Australia.  Currently Brassica napus is the major species being developed as a source of erucic acid for this use.  High erucic acid (HEA) oils have an increasing list of novel replacement use in the chemical industry.  As Australia’s area to canola increases, so does the potential for diseases and contamination with high erucic rapeseed cultivars.  Since crambe does not hybridize (Anon, 1991) with canola, it can be grown in the same regions as canola.  Crambe, being a different oilseed species, therefore offers the potential for plant diversification and an alternative source of erucic acid.

Crambe was evaluated in north - west Victoria, Australia, in the early 1900’s to ascertain agronomic suitability and its yield potential in the wheat belt of Southern Australia.  The species was evaluated at two diverse environments to ascertain the yield potential of the species in low rainfall (Mallee, <350mm) and medium rainfall (Wimmera, 350 to 500mm) environments.

Materials and Methods

Experiments were conducted between 1992 and 1996 at two climatically divers sites: Walpeup and Horsham.  Replicated plots of either 9 or 22m² were sown with a compound fertiliser containing approximately 10-15kg of phosphorous and 10-20kg of nitrogen sown with the seed.  Seed was sown at 20kg/ha and weeds controlled using similar management applied to that for canola.

Yield and Agronomic Performance

In eight trials, the species failed to yield on three occasions for different reasons in different environments (once in the Mallee and twice in the Wimmera).  Failures were attributed to lack of rain and inadequate weed control.  Grain yields varied from < 100 to 2470kg/ha.  Control line at Horsham was Eureka (B.napus) 1234kh/ha in other years site mean was used as the control.

Crambe abyssinica produced higher grain yields in the low rainfall environments during the period of evaluation, figure 2.  As indicted in figure 1 and table 1, season accounted most of the variation.  There were also significant differences in yield between the breeding lines tested.  Days from sowing to flowering varied from 88 to 110 days for C. absyssinica compared to B. juncea (90) and B. napus 108 days during 1992/93 at Walpeup.  Early maturity is critical in the low rainfall regions to maximise yield and oil content as temperatures increase and rainfall usually diminishes or is unreliable as the plants develop to maturity.

Figure 1.  Grain yield for thirty-one Crambe lines grown amid 1992 and 1996.

Annual rainfall for the Walpeup sites was considerably above the average (339mm) in 1992 (537mm), and 1995 (403mm), slightly above in 1993 (361mm), and about average in 1996 (343mm).  The relatively high grain yields obtained in 1996 most probably reflect the cooler spring temperatures experienced post anthesis and during seed maturation.  Rainfall at Horsham in 1992 was 501mm which was above the long term average of 422mm.  Its probable that the wet spring and above average rainfall during seed maturation, contributed to the poor average yields at Horsham.  As the crop was new for Australian growing conditions, hence new to agronomist, thus general crop management would also be reflected in the yields obtained.

Table 1.  Site grain yields variation for Crambe grown between 1992 and 1996.

Statistical variation for Crambe grown between 1992 and 1996
Year	1992*	1992	1993	1995	1996
Site	Horsham	Walpeup	Walpeup	Walpeup	Walpeup
No of lines evaluated	10	15	54	20	18
Site mean (kg/ha)	569	1186	1980	800	1276
Site range (kg/ha)	100-1649	976-1399	730-2427	604-1018	739-1676
Cv (%)	29.7	9.6	40.5	18.3	10.1
SED	173	107	711	126	110
I.s.d. (5%)	373	222	141	256	224

Oil Quality

Grain oil content varied between 35.6 and 42.8% (mean 38.90%) for twenty-five samples analysed from the 1996 Walpeup site.  A level above 40% would indicate the crop has potential to be an economic proposition provided seed yield and market price were similar to that for canola.  Figure 2, provides an indication of fatty acids levels.  Erucic acid content for the sample data presented varied between 54.9 and 60.0 % with a mean of 56.9% for 141 samples analysed indicating that it is possible in some years to achieve satisfactory erucic levels in low rainfall environments.

Figure 2. Fatty acid profile for 141 Crambe samples analysed in 1993

Markets

Vegetable oils, unlike their cousin mineral oil, are a renewable resource, have rapid bio-degradability and are seen as having reduced health hazards.  HEA oils have the special attributes that make them an ideal source of raw material for the manufacture of a range of industrial products.  Crambe, like other vegetable oils, are durable and possess high smoke and flash points whilst retaining stability and oiliness at high temperature.

Y         Crambe oil is an ideal source of long chain fatty acids.

Y        Useful as an industrial chemical feedstock; ie. Erucamide, behenic acid; behenyl alcohol and ethylene brassylate.

Y Uses and potential products derived from crambe oil include: plasticisers; surfactants; nylons; cosmetics; coatings; lubricants; slip agents; pharmaceutical’s; waxes and as a high temperature lubricant.

If crambe was be become an industrial oilseed crop in Australia, it has the potential to revitalise economic activity in many rural sectors of the country.  Production of crambe offers the promise to increase domestic and industrial opportunities in Australia but before it reaches this point it has many obstacles to overcome.  These include evaluation of the crop over large range of environments and increasing the genetic diversity through plant breeding.  Also the acceptance by farmers to produce a satisfactory raw product and an infrastructure to process the grain and the development of a domestic and export market to absorb semi-processed (chemical feedstock), intermediate and end products.

Reference:

Anon, (1993) Crambe Production and Utilisation, BioOptions, Newsletter of the Centre for Alternative Plant and Animal Products, University of Minnesota, Winter, 1993, pp 1-3

Weiss, E.A. (1983) Oilseed Crops, Chpt. 10. Crambe, niger and jojoba, Tropical oilseed crops. – Tropical agriculture series, Longman Group Ltd. Pp463-485