New Zealand has been settled by Europeans for 170 years with the total population now 3.3 million. About 18 million hectares are occupied with pastoral farming being the major form of land use. In 1988, New Zealand had 65 million sheep, 8 million beef and dairy cattle, 1.3 million goats, and 0.6 million farmed deer. Primary products from these stock, forestry products, fruit and vegetables, and fish make up 64% of the New Zealand export trade of $NZ15 billion ($NZ = 0.59 US$, 1991). The important point about this trade is that, with the exception of fish, it is based on animals and plants which have been introduced into New Zealand over the past 150 years. The pastoral industry is based on the European pasture species perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), the forestry industry on the Monterey pine (Pinus radiata D. Don) from coastal California, and the fruit industry on the Eurasian apple (Malus x domestica Borkh.) and the kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang & A.R. Ferg.] from China.
The new crops program is carried out at a number of research stations which span the major island environments (Fig. 1). Climatic recordings from these research stations or close by, listed in Table 1, indicate the temperate nature of the New Zealand environment. In summer, temperatures above 30°C are uncommon and in winter, snow is normally only a one or two day phenomena in the southern regions. There are six programs: new export vegetable crops; European and Asian medicinal herbs; culinary herbs and essential oils; edible fungi; fruit; nuts; and ornamentals.
Subsequent to an examination of Japanese market information, two crops, wasabi [Wasabia japonica (Miq.) Matsumara] and myoga ginger (Zingiber mioga Roscoe), were identified as having strong market potential. Research began on wasabi in 1982 and myoga in 1983.
Wasabi plants grow poorly in New Zealand in full sunlight and artificial shading is required to keep the light levels below 700 µmol m-2 s-1 otherwise the plant is liable to wilt. Japanese recommendations of using 50% shade cloth were inadequate under New Zealand conditions and a further 30% shade cloth was required during the summer. Further research on the shade requirement of wasabi is needed.
The initial New Zealand trials on wasabi were established in large concrete troughs filled with rock and gravel similar to the tatami ishi wasabi beds of Shizuoka, Japan. Spring water of 13° to 14°C was flowed over the beds at about 160 liters/min. Unrooted cuttings were planted at 25 cm centers and the crop grown for two years. Sequential harvests from 15 months indicated that there was a need to leave the crop at least 18 months before harvest to achieve a reasonable production of stems over 50 g (Table 2).
Wasabi has a number of major pests and diseases and is known to suffer from various mosaic viruses which can cause rapid crop decline if successive crops are grown from infected sideshoot cuttings. Regular spraying is required to control aphids and white cabbage butterfly caterpillars. Leaf diseases such as white rust (Albugo sp.) are also controlled by foliar sprays but the more difficult diseases to control include the stem and root fungal diseases, Phoma and Botrytis and bacterial softrot, Erwinia. Control of these diseases is largely unresolved in the natural running water systems.
Considerable progress has been made in New Zealand in the past 5 years on how to grow wasabi to produce a marketable crop, but it is only the beginning. A greater understanding of the physiology of the crop in relation to its environmental requirements, improved cultivars, and better disease control should all allow higher yields and more efficient production methods to be developed. Research in these areas is underway.
Preliminary research on myoga was conducted in New Zealand by Palmer (1984) and following an investigation of Japanese production systems (Follett 1986) further plants were introduced. The plant is established vegetatively from rhizome sections with faster and more even plant emergence from coolstored rhizomes (Follett 1991). The plant is frost sensitive and dies down in winter but the dormant rhizomes have proved to be quite winter hardy (Palmer 1984). Myoga is vigorous and largely disease and pest free when grown on free draining soils, although rhizome rotting from Fusarium and Pythium species has been noted on poorer drained soils. Under New Zealand conditions, myoga topgrowth sunburns and becomes chlorotic without shading and consequently trials have been established under 50% shade cloth. A comparison is presently being made between artificial shade and natural shade given by spaced Paulownia (Paulownia elongata S.Y. Hu) trees.
Myoga production beds established with 30 cm between rhizomes and 1 m between rows have yielded 6.75 t/ha of flower buds in the second year. This is comparable to Japanese production levels. The flower buds develop from underground stems on the edge of the plant mass and to achieve top quality produce, the buds should be picked before they emerge and turn green. To facilitate this, a 10 cm layer of sawdust was applied so that the buds could be located by fossicking and picked. Picking was carried out every 2 to 3 days over a 2 month period.
Myoga is a very new crop in New Zealand with little grown commercially. There remains considerable research to be undertaken in defining its agronomic management but research results to date and the successful test marketing of New Zealand grown myoga indicate that it is likely to be a successful new crop for New Zealand.
Medicinal Herbs There is a large and expanding international market for medicinal herbs and plants for the manufacture of pharmaceuticals (Principe 1989). New Zealand has no significant production of these products although in the late 1970s commercial extraction of solasodine from the native Solanum species (S. aviculare Forst., S. laciniatum Ait.) was begun but later abandoned (Mann 1978; Mann et al. 1985). Nevertheless, the New Zealand environment provides good conditions for the growth of a wide range of medicinal herbs and in many instances they are familiar as weeds. Examples include dandelion (Taraxacum officinale G. Weber), St John's wort (Hypericum perforatum L.), horehound (Marrubium vulgare L.), burdock (Arctium lappa L.), Variegated thistle [Silybum marianum (L.) Gaertner], briar rose (Rosa rugosa Thunb.), and hawthorn (Crataegus monogyna Jacq.).
The current research program is focussed on understanding the agronomic requirements of seven medicinal herbs: coneflower [Echinacea purpurea (L.) Moench], valerian (Valeriana officinalis L.), Arnica montana L., dandelion, feverfew (Chrysanthemum parthenium Pers.), goldenseal (Hydrastis canadensis L.), and ginseng (Panax ginseng C.A. Mey., P. quinquefolius L.). Test marketing of samples from preliminary research on valerian, dandelion, rosehips, and chamomile [Chamomilla recutita (L.) Rauschert] has already shown that these crops can be produced to international market standards. Collections of a wide range of European and Asian medicinal herbs are being assembled for preliminary evaluation of both their growth potential and quality assessment before proceeding to more sophisticated agronomic programs. A Plant Extracts Research Unit provides the quality assessment of the medicinal herbs and also produces plant extracts for examination of their biological activity. This research program is in its infancy and although few results are available, the initial indication is that a wide range of medicinal herbs should be able to be grown successfully in New Zealand.
The current research program seeks to systematically define the oil yield, composition analysis, and international quality assessments of a number of species (Table 3). The results have been very encouraging from this research and commercial extraction of essential oil and sclareol from clary sage is currently under investigation. Agronomic trials have been established to examine the influence of cultivars, environment, weed control, time of harvest, and distillation on oil yield and quality.
The current research program is directed at developing techniques to establish and produce the sought after mycorrhizal fungi, black truffle (Tuber melanosporum Vitt.), white truffle (T. magnatum Pico.), matsutake [Tricholoma matsutake (S. Ito & Imai) Sing.], and cep (Boletus edulis Bull.). Research has successfully devised techniques to inoculate black truffle onto oaks and hazels and although the fungus is evident in the field no truffle production has yet occurred (Hall and Brown 1989).
There is a small and developing industry on macadamia (Macadamia integrifolia Maiden & Betche, M. tetraphylla L.A.S. Johnson) nuts in New Zealand but low yields limit the commercial success (Richardson and Dawson 1991). Research is continuing on evaluation of cultivars from mainly Australian and Hawaiian sources and investigating the effect of pollination and nutrition on crop yields to highlight possible ways to increase yields.
Preliminary research has begun to better define pollination of chestnuts (Castanea sativa Mill., C. crenata Siebold & Zucc.) and identification and control of fungal pathogens which spoil stored nuts. Small commercial plantings of chestnut have taken place based mainly on superior selected trees from local seedlings and there is a need for further cultivar evaluation.
Biogeographic principles are being used to pinpoint sources of appropriate plant material for new plant introductions into New Zealand where there are perceived market potentials not currently being addressed. Particular emphasis is being directed towards sourcing plants from the enormous germplasm resource of South America. Species collected are fed into the herb, essential oil, fruit, and ornamental programs. New ornamentals obtained in South America such as some Begonia, Ennealophus, Fuchsia, and Tibouchina species which are new to New Zealand are evaluated for growth habit, flowering behavior, and postharvest shelf life to estimate their potential as cut flowers or potted plants.
|Research station||Rainfall (mm)||Mean air temp. (°C)||Avg. daily range (°C)||Mean Jan. air temp. (°C)||Mean July air temp. (°C)||No. degree days above 10°C||No. air frost free days|
|Stem yield (t/ha)|
|Harvest time (mo.)||Mean stem wt (g)||Total stem wt/plant (g)||Stems/plant |
|<20 g||20-50 g||>50 g|
|Scientific name||Common name||Favorable |
|Artemisia dracunculus L.||French tarragon||40|
|Carum carvi L.||Carraway seed||100|
|Coriandrum sativum L.||Coriander seed||16||yes|
|Hyssopus officinalis L.||Hyssop||---||yes|
|Lavendula angustifolia Mill.||Lavender||30|
|Lavendula xintermedia Emeric ex Loisel.||Lavandin||50|
|Lavendula latifolia Medik.||Spike lavender||35||yes|
|Mentha xpiperita L.||Peppermint||50|
|Mentha spicata L.||Spearmint||---|
|Origanum vulgare L.||Oregano||110|
|Rosa damascena Mill.||Rose||---|
|Salvia officinalis L.||Sage||60||yes|
|Salvia sclarea L.||Clary sage||50||yes|
|Thymus vulgaris L.||Thyme||40||yes|
|Fig. 1. Location of research stations involved in the New Zealand new crop program.|