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AIR2-CT93-1817
Vegetable Oils with Specific Fatty Acids (VOSFA) Agricultural and Industrial Development of Novel Oilseed Crops - MAFF Final Summary Report |
MAFF - UK Final Summary Report
SCIENTIFIC REPORT
Introduction
Within the proposal for the VOSFA project, which was jointly funded by MAFF and the EC, the species Calendula officinalis, Dimorphotheca pluvialis, Euphorbia lagascae, Lesquerella grandiflora and Lunaria annua had been identified as potentially suitable for cultivation in Europe and containing a range of oils with interest to industry. The ADAS Bridgets Research Centre had been involved since the late 1980s in screening a wide range of potential new crop species. Recent evaluations had included Calendula officinalis and Lunaria annua (Cromack et al 1993, Cromack 1991) which indicated that these species had sufficient potential to justify further evaluation under UK climatic conditions. There was a scarcity of information on the agronomic management of the selected species, particularly under European conditions. This limits the field evaluation of production potential and commercial introduction. Weed control and plant establishment were identified as among the most important aspects of crop agronomy to document.
The objectives of the research to be conducted by the ADAS over the period 1994 - 1997, were to field evaluate the seed and oil production potential of the species Calendula officinalis, Dimorphotheca pluvialis, Euphorbia lagascae, Lesquerella grandiflora and Lunaria annua, under the climatic conditions of south west England and to identify limitations to commercialisation. As wide a range of genotypes as possible were used, concentrating on material provided by partners. A range of agronomic studies were carried out to provide basic information to improve the management of the species under evaluation. Specific experiments were designed to determine the effect of weed competition on production and to identify crop safe and effective herbicides programmes for the species Calendula officinalis, Euphorbia lagascae, Lesquerella grandiflora and Lunaria annua, to define optimum plant density of Calendula officinalis and Lunaria annua and to devise harvesting techniques for the semi-indeterminate species Calendula officinalis.
RESULTS AND DISCUSSION
Evaluation of production potential
Calendula officinalis
The establishment of Calendula officinalis was satisfactory in all years, except for 1997 when herbicide damage occurred The best accessions produced a consistent seed yield of over 2.0 t/ha and a maximum yield of 2.7 t/ha in the highest yielding year 1996. There were differences between accession in maturity and seed yield. Later maturing and decorative cultivars, producing mostly larval seeds, tended to be lower yielding, however there was considerable variability between years. Above average rainfall in July/August resulted in continued flower production, which delayed maturity and made harvest more difficult. The most significant pest encountered was the caterpillar of Heliothis peltigera which in two years rapidly colonised plants but was easily controlled by insecticide application. Seed oil and calendic acid content showed more variability between accessions than between years. The seed oil range was between 13 and 21 % and the calendic acid range between 39 and 52 %. Taken over years the accessions hens and chickens, double lemon coronet and CPRO-DLO 879144 and 880557 produced the highest yields of oil and calendic acid.
The establishment of Dimorphotheca pluvialis and Euphorbia lagascae was variable. The latter was more robust and always produced full ground cover. Differences between accessions for most characteristics were small. The indeterminate flowering and seed shatter characteristics of Dimorphotheca were the major field problem encountered, the former was enhanced by rainfall in July and August. As a result sequential hand harvesting was the only means of accurately measuring yield potential. Harvesting frequency was restricted to 2-4 occasions over a 2-4 week period to simulate the maximum possible yield in a field situation. Yields averaged 478 kg/ha and only in one year exceeded 750 kg/ha. Seed oil and dimorphothecoleic acid were relatively stable over seasons averaging 20.5 % and 54 %.
Euphorbia lagascae establish satisfactorily and produced vigorous vegetative growth. The indehiscent characteristic of the accessions available made it difficult to accurately estimate seed yield. In practice the crop was cut when the secondary layer of seeds had started to shed. Considerable seed was lost prior to this time and some later produced seeds were immature at harvest. Despite the technique used seed yields were relatively consistent between years averaging 1.1 t/ha. Seed oil content was high and consistent at 47.8 O producing an oil yield averaging 526 kg/ha vernolic acid content showed some variability between seasons averaging 56.6 %.
Lesquerella grandiflora was sown in three years but despite the use of a fine firm seedbeds and shallow sowing establishment was from zero to very poor. In only one year was a modest crop achieved, crop vigour was poor and yield less than 500 kg/ha. Flea beetle was a consistent problem at establishment, maximum crop height was 20 cm so that hand harvesting was the only option. The crop does not appear suited to the soils and climatic conditions of Western England.
Lunaria annua was sown on three occasions, successful crops were established in two years. Dry conditions in mid summer were the main cause of establishment problems with flea beetles evident in some years. Once established crops grew satisfactorily but further plant losses occurred over winter caused by wet soil conditions and slug damage. In 1995 and 1997 despite low plant density full ground cover was achieved by vigorous spring growth. Although flowering was protracted seed shatter was not a significant problem when the crop was direct harvested by combine. Differences in growth characteristics between cultivars were small but significant yield differences were recorded, Kings Crown Purple and CPRO-DLO 883158 producing consistent yields in both years while Jahng was variable. There were significant seasonal effects on oil and fatty acid composition and smaller differences between accessions. Albugo candida was the most serious disease encountered, there appeared to be limited genetic resistance, with Jahng the most resistant, but a comprehensive fungicide programme in 1996/7 limited the development of the disease.
Agronomic investigations
Calendula officinalis
In 1994 plant establishment of cv. Pot Marigold was poor and patchy as a result of a variable drilling depth and some drill blockages caused by large hooked seeds. Establishment ranged from 35 % to 56 % of viable seeds. As a result plant densities were lower than the target with a maximum of 81/m2. Seedbed conditions in 1995 were excellent and some of the larger winged seeds were removed from sample of cv. Single Wild Type. As a result establishment was good ranging between 62 % and 83 % of viable seeds enabling the achievement of all but the highest target density.
Plant establishment was generally inferior at higher seed densities. In 1994 all plant densities produced full ground cover before flowering, but under the dry conditions of 1995 densities below 40/m2 failed to achieve full ground cover. Crop height and crop developments were recorded but differences were not significant.
Yields in 1994 were low due to the use of the late maturing accession and a wet early August, which extended crop maturity, and showed no significant effect of plant density. In 1995, under favourable weather conditions, there was a significant effect of plant density. Yield increased up to 40 plants/m2. The results suggest that the optimum plant density is between 40 and 60/m2 Plant density had no effect on seed oil content.
Overall, herbicide treatments had no significant effect on crop vigour or plant density. However in 1991 pendimethalin at 1320g a.i./ ha tended to reduce crop vigour and significantly reduced crop ground cover. In 1995 no adverse effect from this treatment was recorded. In 1995 post-emergence phenmedipham at 1110g a.i./ha significantly reduced crop vigour but no damage was recorded in 1994. It is suggested that the hot dry conditions put the crop under greater stress in 1995 thereby predisposing it to greater herbicide damage. Most herbicide treatments increased yield in comparison to the untreated control but yield differences between herbicide treatments were not statistically significant.
The main broad leaved weed species were Chenopodium album, Polygonum convolvulus, Polygonum aviculare, Atriplex patula and Galium aparine. Total numbers averaged 28/m2. Weed density was significantly reduced by pre-emergence application of isoxaben plus pendimethalin, isoxaben plus triQuralin, trifluralin pendimethalin. chlortllal-dimethyl, metazachlor and propyzamide at 1000g a.i./ ha. Trifluralin and metazachlor gave the most consistent control of the weed spectrum found in this experiment, and as a result would be the recommended treatments. The only post-emergence herbicide investigated, phenmedipham, cannot be recommended because of its adverse effect on the crop. As a result of the above recommendations in 1997 the herbicide metazachlor was used as an overall herbicide for all experiments but its application to a very dry soil followed immediately by 31.5mm of rainfall in 48 hours caused catastrophic effects on crop growth probably due to the leaching of herbicide to the root zone. Metazachlor cannot therefore be recommended.
Herbicide damage and a wet August delayed maturity and produced a Calendula officinalis crop containing flowers, green and brown seed through the harvesting period, the maximum level of brown seed at 65 % was well below target. The pre-combine seed yield was consistent throughout the harvesting period but the percentage harvested by the combine was less than 50 %, and was at a maximum on 30 September. This harvesting action followed six days of dry weather, it is suggested that crop moisture content at harvest may be more important than the treatments investigated. Combined seed yield and trash content was unaffected by desiccation date and interval to harvest.
Combine settings significantly affected seed yield and trash content. The highest yield was produced by two settings, 600 rpm drum speed, low wind volume, 15 mm straw bed sieve and 800rpm drum speed, low wind volume, 25 mm strawbed sieve. Increasing wind volume and reducing strawbed sieve size reduced trash content of the sample but significantly reduced seed yield. It is suggested that that low wind volume and a large strawbed sieve opening are important to minimise losses and maximise harvested seed yield, but this will be at the expense of seed cleanliness.
Lesquerella grandiflora
The number of plants established was well below target and was significantly affected by herbicide treatment (Table 8). Isoxaben prevented the establishment of any plants, pendimethalin and linuron significantly reduced plant density. All herbicides except benazolin:clopyralid adversely affected crop vigour at some stage during the growing season. Plant vigour tended to improve over the growing period, except following metazachlor application, where it declined. Of the pre-emergence herbicides only trifluralin appeared to show reasonable crop safety, while the post-emergence application of benazolin + clopyralid indicated good crop tolerance. It is concluded that the species is particularly sensitive to herbicides and that further investigations are needed to identify a range of reliably safe options.
Crop growth was very poor, reaching a maximum height of 17 cm and dry matter production of less than 1000 kg/ha. Under these conditions the hand removal of weeds increased whole plant yield by over 60 %, indicating that weed control is of considerable importance for maximum production from this species. Weed numbers overall were low, Stellaria media, Viola arvensis, Chenopodium album and Capsella bursa pastoris were the dominant weeds. All herbicides reduced weed numbers, trifluralin was the most effective of the crop safe materials producing a biomass yield comparable to the hand weeding.
Euphorbia lagascae
The number of plants established was significantly reduced in 1997 by isoxaben and metazachior. Pendimethalin, propachlor and bentazone in 1996 and metazachlor in 1997 significantly reduced crop vigour six weeks after pre-emergence application. In 1996 this effect became less noticeable with time, in 1997 the same trend was observed following pre-emergence treatments but an adverse effect of bentazone was recorded 6 weeks after its post-emergence application. It is concluded that pre-emergence trifluralin, chiorpropham and linuron and post-emergence benazalin+clopyralid appear to be crop safe options. Isoxaben and pendimethalin gave the highest level of weed control in both years. The hand removal of weeds increased whole plant yield by 37 % in both years, indicating that although this species appeared competitive, its biomass production potential was significantly impaired by modest levels of weed competition.
Lunaria annua
In both years initial plant establishment was below target. The only herbicide to significantly reduce crop vigour and plant density in 1994/5 was trifiuralin. Results of 1994/5 identified pre- or early post-emergence application of metazachlor as the optimum first stage in a sequential weed control programme. This formed the basis of the 1996/7 treatments but very dry conditions made this herbicide ineffective. Wet conditions in early autumn resulted in vigorous weed growth which was difficult to contain so hand weeding and contact herbicides were investigated. While paraquat was one of the most effective late autumn herbicides treatments, none significantly reduced spring weed density or increased yield. An autumn and spring sequence of benazolin + clopyralid significantly reduced seed yield. In both years hand weeding throughout the growing period only produced a 17 % yield response over the unweeded control. It is concluded that the species is relatively tolerant of moderate levels of weed competition.
In 1994/5 and 1996/7 establishment of the higher target plant densities was not possible, the range achieved was of 10-90 plants/m2 in 1994/5 and 8 to 43 plants/m2 in the drier 1996/7. Overwinter losses, which were greater in 1994/5, reduced populations further. In both years maximum yield was obtained at spring plant densities of 20 plants/m2 and above. In 1996/7 mid May sowing resulted in improved plant establishment, earlier flowering and a significantly higher seed yield and higher seed oil content than later sowing dates.
Conclusions
From the species evaluated Calendula officinalis appears to offer the most immediate prospect of commercialisation, with yields of the best available genotypes in the 2 to 2.5 t/ha range. While some genetic variation in seed oil content was recorded, levels need to be increased. Crop density of 40 to 60 plants/m2 appears optimum and relatively easily achievable. Isoxaben plus pendimethalin, triiluralin, pendimethalin (1000 g a.i./ha) and chlorthal-dimethyl were identified as effective and crop safe herbicide options. A reduction in the length of the flowering period would ease harvesting problems. Desiccation and direct combining was showed to be an acceptable harvesting method, wind volume and straw bed sieve size were identified as important combine settings but greater understanding of factors influencing harvesting efficiency is needed.
Euphorbia lagascae established and grew successfully but until a non-dehiscent type is available commercialisation is impossible. The harvested yield of about 1 t/ha is likely to be an underestimate of the crops potential. The high oil content of the seed is an encouragement to continue development of the species. The species is susceptible to weed competition but pre-emergence trifluralin, chlorpropham and linuron and post-emergence benazolin+clopyralid are crop safe options.
The establishment of Lesquerella grandiflora posed significant problems, it growth and performance were poor, it was shown to be very susceptible to weed competition and sensitive to many herbicides. It is concluded that the species is not suitable for commercialisation in western Europe.
Establishment problems were experienced because the biennial Lunaria annua needs to be established during the summer, an annual genotype would offer significant advantages. Plant densities above 20/m2 produced acceptable combine harvested yields, differences between genotypes in yield and oil content were identified. Current genotypes benefited from May sowing. The species was shown to be relatively tolerant of weed competition but no consistent herbicide option was identified, an effective early season herbicide option is necessary.
Future work
Following on from the success of the VOSFA project, a further bid was submitted to the EC in 1997 focused on the development of Calendula offcinalis, the species nearest to commercial exploitation. ADAS is the sole UK partner within the consortium of 12 organisations from 5 countries. This project, CARMINA, Calendula as agronomic raw material for industrial applications, was approved by the EC in 1998, with field work beginning April 1st 1998. The ADAS input into this research project is 50% funded by MAFF under NF0503. The ADAS role will again focus on aspects of agronomy. Two major research tasks are planned, one on crop physiology and one on evaluation of variety accessions. Physiology studies will examine the effect of density and nitrogen rate in two distinct phenotypes on crop development and performance. The variety evaluation study will compare accessions from the latest breeding efforts at CPRO and Cebeco in the Netherlands with currently available genotypes in the UK and 3 EU countries.
Another promising species identified under the VOSFA project was Euphorbia lagascae. In view of the important issues which need to be addressed before this crop could be developed further, such as the availability of non-dehiscent types and presence of naturally occurring irritant compounds within the species, a review of current knowledge rather than further research was deemed most appropriate by the VOSFA consortium at this stage. A proposal was submitted to the EC under the 4th Framework programme in January 1998 to provide funding to support a concerted action. This proposal was led by ADAS, involves 15 partners across the EU and was entitled The development of Euphorbia lagascae as a new oil crop within the European Community
Of the remaining species examined under the VOSFA project Lunaria annua is worthy of further study and is of particular relevance to the UK. There is a need to review the progress made to date and determine UK policy towards this crop. Lunaria annua appears to be well adapted to UK conditions, offering the UK a competitive advantage and there are pharmaceutical markets for its nervonic acid and established markets for erurcic acid. This review should take account of the work of the Dutch breeding programme which is beginning to produce better material and the problems identified by VOSFA in terms of weed control and rotational position. The review should determine the likelihood and timescale over which technical constraints could be solved by research and indicate whether further research investment is justified.
| Species | No. of accession years | Yield Kg/ha at 91% DM | Seed Oil % | Specific fatty acid % in seed oil | |||
| Mean | Range | Mean | Range | Mean | Range | ||
| C. officinalis | 36 | 1492 | 269-2750 | 16.6 | 13.4-21.0 | 45.4 | |
| D. pluvialis | 8 | 478 | 313-910 | 20.5 | 18.8-24.3 | 54.2 | |
| E. lagascae | 8 | 1091 | 854-1390 | 47.8 | 46.3-50.2 | 56.6 | |
| L. grandiflora | 3 | 152 | 0-440 | 21.9 | 18.1-25.6 | 51.8 | |
| L. annua | 18 | 1770 | 100-2900 | 29.8 | 24.7-34.7 | 48.6* 23.8** | 43.4-53.4 20.2-28.1 |
*erucic acid **nervonic acid
© Copyright 2006 Policy Statements
Updated
by CPL Press:
03/07/2007
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