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Hewett, E.W. 1993. New horticultural crops in New Zealand. p. 57-64. In: J. Janick and J.E. Simon (eds.), New crops. Wiley, New York.

New Horticultural Crops in New Zealand

Errol W. Hewett

  1. ESTABLISHED FRUIT CROPS
    1. Kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang & A.R. Ferguson] var deliciosa, Actinidiaceae
    2. Apples (Malus x domestica Borkh., Rosaceae)
  2. THE SOUTH AMERICAN CONNECTION
    1. Tree Tomato [Cyphomandra betacea (Cav.) Sendtn., Solanaceae]
    2. Feijoa (Feijoa sellowiana Berg, Myrtaceae)
    3. Pepino (Solanum muricatum Ait., Solanaceae)
    4. Babaco [Carica x heilbornii Badillo m. pentagona (Heilborn) Caricaceae]
    5. Cape Gooseberry (Physalis peruviana L., Solanaceae)
    6. Cherimoya (Annona cherimola Mill., Annonaceae)
    7. Oca or "Yam" (Oxalis tuberosa Mol., Oxalidaceae)
    8. Other Crops
  3. NEW FLOWER CROPS
    1. Calla (Zantedeschia spp., Araceae)
    2. Nerine (Nerine spp., Amaryllidaceae)
    3. Sandersonia (Sandersonia auriantiaca Hook., Liliaceae)
    4. Other Flowers
  4. NATIVE PLANTS FROM NEW ZEALAND
  5. CONCLUSION
  6. REFERENCES
New Zealand, a small country located in the South Pacific (latitude between 35° and 47°S and longitude 167° and 178°E) has a population of 3.3 million. Horticulture is a small but important contributor to the national economy having NZ$1.2 billion export earnings in 1991, 7.4% of total exports (NZ$1 = US$0.54, 1992). Four new fruit crops have been successfully introduced to international trade during the 20th century: avocado, blueberry, kiwifruit, and macadamia (Janick 1991). Of these, kiwifruit has arguably made the largest and most dramatic impact over the last 20 years.

The kiwifruit is a unique fruit with unusual visual (a brown, hairy skin with a spectacular green translucent flesh containing an attractive circle of black seeds around a white pith), nutritive (low calories, high fiber, high potassium, and vitamin C content), and storage (quality can be maintained for up to 12 months in air or controlled atmosphere storage) characteristics. It has successfully captured the imagination of traders and consumers who have paid high prices to purchase this new fruit. Associated profitability has seen kiwifruit planted in large numbers throughout the world during the 1980s.

ESTABLISHED FRUIT CROPS

New Zealand grows a wide range of temperate fruit crops, but only contributes significantly to world trade with kiwifruit and apples. Major efforts are currently underway to improve the existing range of cultivars to exploit consumer demand for new taste and visual sensations.

Largely as a result of the foresight, dedication, perseverance, and skill of the late D.W. McKenzie, major breeding and plant improvement programs are being undertaken by the Department of Scientific Research (DSIR) on a range of crops including kiwifruit, apples, pears, apricots, and a range of subtropical fruits.

Kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang & A.R. Ferguson] var deliciosa, Actinidiaceae

Commercial plantings of kiwifruit in New Zealand are known to have derived from one seed acquisition brought from China in about 1903 by Miss Isabel Fraser, sister of Miss Katie Fraser, a missionary in Xichang. It is possible that the majority of kiwifruit grown in New Zealand (and to a large extent elsewhere especially France, Italy, and Australia) originated from seed from one fruit, certainly from only a few fruit collected from the wild by E.H. Wilson from one region in China (Ferguson 1990). Hence, the present genetic base of existing kiwifruit plantings is extremely limited.

The genus Actinidia is known to have more than 50 species and more than 100 taxa (Liang and Ferguson 1986, Ferguson 1990). The cultivar `Hayward', which accounts for more than 95% of the current kiwifruit plantings in New Zealand today, was selected by Hayward Wright, a nurseryman who has been called "the Luther Burbank of New Zealand horticulture." In the period from 1903 to 1946, when kiwifruit were grown mainly as an ornamental plant, many enthusiastic nurserymen were involved in the propagation, improvement and sale of these novel plants; in particular Bruno Just, Alexander Allison, James McGregor, and Hugh Gorton, made significant contributions (Ferguson and Bollard 1990).

Scientists in DSIR recognized the inherent danger of relying on such a narrow genetic base for the development and continued success of an important new crop. They were also well aware of the diverse range of species, indigenous in China, which while providing fruit for a range of products (jam, pastes, medicines) had not been subject to any concerted or deliberative screening programme for improving size or quality. Since the 1970s there has been a joint effort by DSIR and Chinese scientists to obtain seed material from a broad range of Actinidia species, to grow them together under uniform conditions of cultivation and training for comparison of fruiting characteristics and to obtain diverse material to be used in breeding programmes by traditional or novel molecular biology means.

The genus Actinidia is characterized by having a wide range of growth habits, fruit size, shape, color, and nutritive qualities. Some species are cross compatible and interspecific crosses are easily achieved, while others are incompatible, and interspecific hybrids may only be possible by using recently developed embryo transfer techniques. Three major thrusts are being adopted by scientists involved in the current breeding program:

  1. to obtain improved or different selections from existing plantings or "Hayward lookalikes." Selections already made and under evaluation include: more uniform fruit shape, earlier fruit maturation, hermaphrodite as distinct from diecious plants, more productive plants than `Hayward', higher vitamin C, and reduced flats and fans.
  2. to develop vigor controlling rootstocks which will also offer better flowering after mild winters, produce high export yields, enhance precocity from young vines, and reduce flats and fans.
  3. to crossbreed with other Actinidia species, in particular from A. chinensis Planchon, to produce fruit with smooth skins like a peach or pear, maybe with different colored skins and/or flesh. A. chinensis vines are precocious and high yielding, some are early maturing with good flavor. A range of flesh colors from green through yellow to pink are available, and fruit store for 2 to 3 months. Successful hybridization between A. deliciosa and A. chinensis is likely to produce fruit combining the desirable features of both species. A. arguta (Seibold & Zuccarini) Planchon ex Miquel, marketed as a home garden vine in North America, produces fruit about grape-size, very sweet, with red or green flesh. A green skinned hairless fruit from a highly productive vine has already been produced.
Results from these different approaches already indicate that there is a major potential for a dramatic increase in the range of cultivars of kiwifruit of commercial potential. Even more exciting is the possibility of the emergence of "new" fruits based on the genetic diversity of the Actinidia species. These long term strategic plant improvement programs are financially supported by the kiwifruit industry which recognizes the commercial necessity and opportunities which accrue from successful new cultivar development.

Apples (Malus x domestica Borkh., Rosaceae)

One of the main reasons for the success of the New Zealand apple industry is the ability to provide customers with a range of 5 to 9 distinct cultivars over a 4 to 6 month marketing period. This contrasts with some other apple producing countries which tend to produce only two or three major cultivars. In addition, the New Zealand Apple and Pear Marketing Board has successfully introduced several highly acceptable new cultivars to international trade in recent years. The cultivars 'Braeburn', 'Gala', and 'Royal Gala' have had a major impact in apple markets highlighting New Zealand's reputation of being able to develop and market appealing new fruit sensations.

The late D.W. McKenzie, working for DSIR, with great perspicacity, foresaw the need for a concentrated and directed breeding program to ensure a continuous release of new apple cultivars onto major markets. With perseverance and dedication, he overcame serious opposition in New Zealand, and acting against prevailing international trends, initiated a program to produce a bright red, late maturing highly flavored apple to have a market slot after 'Granny Smith'.

While none of his original selections are likely to achieve major success, subsequent releases from his work, together with hybrids from current programs, are likely to have a substantial impact in the next decade. 'Splendour' x 'Gala' crosses are undergoing commercial evaluation and two are being focussed on by the New Zealand Apple and Pear Marketing Board for test marketing. In particular, GS2085, looks promising. It is a rosy pink cultivar which ripens late in the season with 'Granny Smith'; it has an extremely crisp and crunchy texture with a sweet flavor and a good acid balance. The trees are precocious, like a 'Golden Delicious' in openness and vigor, having good branch angles and carrying good fruit loads on young branches. GS2085 has tolerance to black spot and is less susceptible to mildew than existing cultivars.

Later crosses, including selections from a collaborative program with Japanese plant breeders, are equally, if not more exciting. It is anticipated that a portfolio of selections will be produced which will provide quite different taste and texture sensation for consumers contrasting markedly with major cultivars available today. Enhanced pest and disease tolerance/resistance is another major objective in the ongoing pome fruit breeding program in an attempt to reduce the importance of pesticides in producing high quality fruit. A pear breeding program is also underway in DSIR, but this is less advanced than the apple projects. Recognition of the strategic importance of providing new apple cultivars has resulted in considerable financial input from the New Zealand apple industry to this program.

THE SOUTH AMERICAN CONNECTION

In tropical South American countries, at altitudes between 2,000 and 3,000 m, there occur endemic fruiting plants that are really warm temperate species. Many of these appear to be well adapted to warmer parts of New Zealand. Over the past 20 years, both private and Government sponsored expeditions have visited a number of countries, including Colombia, Ecuador, Peru, Chile, and Brazil to obtain propagating material for evaluation under New Zealand conditions. The rapid destruction of natural rainforest vegetation in several of these countries is placing many precious food plants at risk of extinction; there is an urgent need to collect and preserve as many of these plants as soon as possible if they are not to be lost forever. New Zealand has been fortunate in being recipients of some most interesting fruit and vegetable crops from South America, many of which were common foods of the Incas (Veitmeyer 1991).

Tree Tomato [Cyphomandra betacea (Cav.) Sendtn., Solanaceae]

The tree tomato [renamed the tamarillo in New Zealand, not to be confused with the tomatillo (Physalis ixocorpa Brot.)] is an egg shaped/sized, bright red fruit developed in New Zealand from seed thought to have been obtained from a missionary in Ecuador early this century. In the wild, the fruit is generally small, splotchy and yellow or pale red in color (Veitmeyer 1991). Large red-fruited strains were developed by nurserymen in New Zealand, and recently large golden colored cultivars have been produced.

Tamarillos are rapidly growing trees which produce good crops after 18 months. They are frost tender which limits their distribution. Fruit is highly attractive, but some people find the skin and flesh too astringent to make it a popular fresh fruit. While the fruit has a high vitamin C content, it has a limited storage life, suffering from chilling injury and postharvest pathogens if maintained below 5°C for any sustained period of time. Fruit processes extremely well. They can be frozen or canned and can be used for a range of products including jam, pulp, puree, chutney, and juice; there is considerable potential for combining with milk products such as yogurt.

Unfortunately, tamarillo trees are easily infected with tamarillo mosaic virus, which results in production of blotchy, streaked unattractive fruit. Until disease resistant stock can be obtained, opportunities for existing tamarillo cultivars are limited. A wide range of seeds have been collected from indigenous tamarillo plants in South America and these are currently under evaluation.

Feijoa (Feijoa sellowiana Berg, Myrtaceae)

Originating in the plateau lands of southeast Brazil, the feijoa, known as pineapple guava in California, has been grown in New Zealand for many years. It has a shrub-like growth habit producing attractive flowers. It is more hardy than tamarillo, being able to tolerate mild winter frosts. In California, it is grown mainly as an ornamental hedge, while in southern Russia and Israel, it has been grown as a commercial fruit crop. Until recently, most plantings in New Zealand have been with seedlings, resulting in extreme variation in fruit size, shape, flavor, and keeping quality. Over the last decade, a number of improved selections have been made and the availability of grafted plants is ensuring consistency in fruiting.

The ovoid green skinned fruit with vanilla-colored flesh has a very sweet and aromatic taste when eaten fresh. Flesh has to be scooped as the skin is bitter. No satisfactory maturity index has been developed so it is difficult to determine optimum harvest maturity. Fruit catching structures are placed under trees by the serious feijoa growers in order to prevent fruit dropping to the ground when ripe; if this occurs fruit is likely to be damaged and become infected with postharvest pathogens. Recent research has produced cultivars with large fruit having thin smooth dark green skins, strong aromatic flavor, good sugar/acid balance, smooth texture with a minimum of grittiness, and a moderate storage life. Fruit may be canned to create a pleasing product.

Pepino (Solanum muricatum Ait., Solanaceae)

The pepino is a small, shrubby plant which produces large (up to 15 cm diameter) fruit with a sweet smell, subtle flavor, and attractive yellow/golden skin color often with purple stripes. It is grown widely in the north of South America and cultivated extensively in Chile. Seed material, introduced to New Zealand in 1973, produced extremely variable fruit with a range of shapes and flavors. It grows well in New Zealand, generally in the same climate as tomato. Early sales of seedling fruit by entrepreneur growers wanting to cash in on this new crop, created serious market problems, as fruit was often small, bitter, unattractive to both the eye and the palate.

A selection and breeding programme by DSIR scientists in conjunction with a committed and enthusiastic grower, has led to the production of several outstanding cultivars. However, best crops seem to be produced under protected cultivation and many management problems involving nutrition temperature, light, and maturity indices have still to be solved.

In spite of an apparently receptive market in Japan for high quality pepinos, this industry has virtually lapsed for want of necessary research input.

Babaco [Carica x heilbornii Badillo m. pentagona (Heilborn) Caricaceae]

The babaco is native of Ecuador and is a hybrid between two Andean papayas, producing more and larger fruit than the mountain papayas. It was introduced to New Zealand in 1973, but popularized by an ardent nurseryman who made numerous visits to Ecuador to collect this and other exotic fruit material.

Babaco is extremely productive, producing large (2 kg) green, torpedo shaped fruit hanging in clusters around the trunk. The fruit has a subtle flavor when ripe; it is very refreshing to eat and make an acceptable and healthy juice. Although difficult to propagate initially, many plants were sold to real and "would-be" horticulturists during the boom times of the early 1980s. However, this crop has not been a commercial success either locally or for export, possible because of their novelty (and lack of promotion) and their large size (they are too expensive for the consumer wanting to try something new).

Cape Gooseberry (Physalis peruviana L., Solanaceae)

These plants grow all over the Andes and were fruit of the Incas (Veitmeyer 1991). Cape gooseberries (which are neither gooseberries nor from the Cape; seeds were obtained from the Cape of Good Hope late last century) are grown on a few small properties in New Zealand. Production is small and fruit is supplied mainly to the local market. Removed from the paper-like husks, the attractive yellow marble-sized fruit makes an extremely tasty jam. Fruit has a high vitamin A, B, and C content, is a rich source of carotene, phosphorous, and iron, and also contains vitamin P. It may be eaten fresh, in salads or in cocktails. No research effort is being made in New Zealand to improve this crop.

Cherimoya (Annona cherimola Mill., Annonaceae)

Considerable interest is currently being shown for this green-skinned, softball-sized fruit sometimes called "the queen of subtropical fruits." A range of cultivars have been introduced from Ecuador, Chile, and Peru for evaluation in warmer climates in New Zealand and several commercial orchards have been planted. A reasonable market potential seems to exist for this very tasty fruit (enhanced by the recent freeze in California which destroyed a major production area). However, selection of cultivars for good production of high quality fruit in marginal New Zealand climatic conditions is still necessary; fruit with fewer seeds and extended shelf life are also required before this fruit could become a substantial export earner from New Zealand.

Oca or "Yam" (Oxalis tuberosa Mol., Oxalidaceae)

The oca (or yam as it is called in New Zealand) is a small, red, waxy, crinkled tuber was probably a staple food item of the Andean Indians (Veitmeyer 1991). They are grown on a very small scale in a localized area in New Zealand and sold only on the local market. The tubers have a tangy, acid nutty flavor and are eaten mainly with roast dinners. The original planting material probably came from Chile to New Zealand in the late 1800s with immigrants. Oca does not seem to be widely grown outside of South American countries and so appears to qualify as "one of the lost crops of the Incas" (Veitmeyer 1991).

Other Crops

A range of other unusual and exotic South American food crops are being grown in New Zealand, generally by enthusiastic horticulturalists. These include: naranjilla (Solanum quitoense Lam., Solanaceae), which produces an orange hairy fruit which makes a green frothy drink, and has a flavor reminiscent of pineapple and strawberry; capulin cherry (Prunus capuli Cav., Rosaceae) a red skinned, green fleshed fruit with excellent flavor; yacon (Polymnia sonchifolia Poepp. & Endl., Asteraceae) a root vegetable, which when eaten uncooked, is very crunchy, watery to translucent, and sweet. Any attempt to improve or develop these plants further is being undertaken by private individuals.

Another fruit vegetable that has received some interest in recent years is the kiwano or African Horned Melon (Cucumis metuliferus E.H. Mey. ex Schrad., Cucurbitaceae). It grows on the fringes of the Kalahari Desert in Africa and was introduced to New Zealand during the 1970s. The orange spiny fruit with intensely green flesh is extremely attractive. The fruit has many seeds, a subtle flavor, and has an excellent storage life at room temperature. However, it is more of a novelty crop and has not undergone commercial development.

NEW FLOWER CROPS

New Zealand is a very small producer of flowers by international standards. Orchids are the most important flower in terms of exports. However, there are a few new flower types that have been developed which are poised to make a contribution in the near future. Private breeders are also producing international prize winning cultivars with traditional flowers.

Calla (Zantedeschia spp., Araceae)

Originating in Southern Africa, several New Zealand nurserymen have specialized in developing an extensive range of new brightly colored callas. These are versatile plants and can be used as bedding plants, pot plants, and cut flowers. A considerable amount of basic research has been undertaken at Massey University to understand the factors controlling the growth cycle of these plants, including flowering, dormancy, and productivity, with a view to producing a production management blueprint for purchasers of the export tubers and plants (Funnell et al. 1988). A recent innovation has been to develop a miniature potted version of the white arum lily (Z. aethiopica cv. Childsiana) which holds considerable potential as a decorative or commemorative living momento.

Nerine (Nerine spp., Amaryllidaceae)

In recent years, New Zealand has obtained ownership of probably the most extensive collection of nerine species and cultivars in cultivation in the world. A very limited number of growers are involved in evaluating this collection in New Zealand conditions, with a view to exporting both bulbs and a range of diversely colored cultivars.

Sandersonia (Sandersonia auriantiaca Hook., Liliaceae)

A protected genera now in South Africa, Sandersonia stock was obtained by a New Zealand nurseryman over 70 years ago, but commercial development has been very slow. Grown from tubers, the plants produce beautiful, orange, bell-like granny's bonnet shaped flowers which have a reasonable shelf life. Both tubers and cut flowers are grown for export.

Other Flowers

New Zealand has some highly accomplished private flower breeders who are making major advances in new cultivars. Prominent among these are: Keith Hammett who has gained international awards for his outstanding new selections of dahlias, sweet peas, and carnations; Sam McGredy, originally from Ireland, who now resides in New Zealand and continues to produce world class roses with infinite shape, color, and aroma; Bill Doreen who has been producing a wide range of colorful and exciting lilies for many years.

A number of other flower crops are being grown by committed enthusiasts; these include peony, leucodendrons, limonium, and gypsophila. A recent novel development has been the production of miniature flower plants of Leptospermum spp. (Myrtaceae) and kowhai [Sophora spp., Leguminosae (subfamily Faboideae)].

NATIVE PLANTS FROM NEW ZEALAND

New Zealand has a unique flora. Many indigenous shrubs and trees are not well-known in other parts of the world. Some of these have potential for pot plants or foliage. While some have been developed by nurserymen for local sale, most of the range of foliage and flower types available have not been utilized as commercial products.

A number of Cordyline spp. and Phormium spp. (both Agavaceae) have been selected; these include dwarf species, and selections with a range of foliage from deep reds through yellow to green, as well as a range of variegated types.

One tree with considerable potential is the pohutakawa or New Zealand Christmas tree (Meterosideros spp., Myrtaceae). In the wild, it grows as a huge gnarled tree, often protruding precariously from high cliffs overlooking the sea. Trees have brilliant crimson red flowers which cover the whole tree in December in New Zealand. It is possible to produce trees in pots and to induce flowering within two years of planting. Further research is required to manipulate growth and flowering with more precision before a successful export industry can develop, but there is considerable potential for this spectacular specimen.

Hebe spp. (Scrophulariaceae) are common throughout New Zealand. Many have been developed as garden and potted plants, as much for their varied foliage as for their range of flower types. Increasingly, these Hebes are being developed in countries other than New Zealand, (Denmark) as successful commercial nursery plants.

CONCLUSION

Possingham (1990) identified two contrasting influences at work in horticultural industries in developed countries. On the one hand there is a strong move to develop new and exotic crops, often drawn from diverse species growing in the wild, which have the potential to produce good profits for growers and others involved in horticultural trade. On the other hand, there is a reduction in the number of cultivars being grown as market requirements define apparently narrower quality characteristics.

New Zealand horticulture generally follows the first trend. While Maoris, the original inhabitants of New Zealand, brought several vegetable crops, notably the sweet potato, with them from the Pacific, the majority of new plant introductions occurred with the arrival of English settlers in the late 19th century.

Most of the traditional horticultural crops grown in New Zealand are well known in other fruit growing countries in temperate climates. Introductions of apples, pears, stonefruit, berryfruit, citrus, flowers, and ornamental plants continue to this day from diverse international sources.

However, there has been a large element of serendipity in the introduction of new or different plants. Missionaries, travellers, explorers, and visitors have all had an influence on the introduction of new and unusual plants. The kiwifruit from China and the range of species from South America exemplify this fact.

Highly skilled, observant, and entrepreneurial nurserymen probably had the major role in transforming wild growing species into potential commercial cultivars. Many of these nurserymen were very talented plantsmen who initiated plant improvement programs themselves by selection and breeding. The seminal influence of Alexander Allison, Bruno Just, and Hayward Wright in the initial development of the kiwifruit has been well documented (Ferguson and Bollard 1990). The influence of nurserymen on the development of other crops mentioned in this article is not documented.

Invariably, success depended on the efforts of a "champion" of the crop. Whether this champion was a nurseryman, a grower, a scientist, or a marketer, almost without exception, any product which has achieved any economic significance in New Zealand can be identified with an enthusiastic, committed, and skillful plantsman who are unabashed advocates for their particular crop.

A more recent feature of new crop development in New Zealand has been the involvement of Government scientists, mainly from DSIR, but also from the Ministry of Agriculture and Fisheries and from Universities. The Government has funded a number of plant improvement programs, both in selection and breeding in major and minor crops, and the scientists involved have worked closely with growers and nurserymen. This collaboration has accelerated in the last two decades, particularly but not exclusively with the major crops such as apples and kiwifruit.

Both of these industries have well developed infrastructures and a strong marketing role. Industry personnel have agreed with scientists on the strategic importance of developing an extended range of cultivars which should provide a market advantage for this country in the future. Input from marketing experts to the scientists breeding program is an important characteristic of today's efforts which are underpinned by both Government and industry funding.

While many other groups have developed to represent the collective interests of those producing or marketing particular products, they lack the organizational structure and the financial success of the major product groups. Consequently less "seed" money has been available for attracting subsequent Government research effort.

Recent structural and philosophical changes have occurred in science organization in New Zealand which is impacting on research carried out on minor horticultural crops. The 1980s have seen the introduction of "user pays;" that is research perceived to bring direct benefit to an individual or an industry is expected to be increasingly funded by that individual or industry. Therefore, while the apple and kiwifruit industries currently contribute nearly $6 million to research, and as a consequence still receive substantial Government support, minor industries are in no position to provide enough funding to attract significant Government support. In spite of the fact that there is potential for commercial success from one or more of a range of "sunrise" crops, (i.e. crops at early stages of development and perceived to have potential for growth), the Government policy of not picking winners and not funding research on crops/sectors that do not provide research funds, means that the effort being directed into minor crops has diminished drastically over the past eight years.

New Zealand has turned a complete circle. Successful development of new and exotic crops in the future will come again from the private nurseryman, the enthusiastic amateur horticulturist, the perceptive grower, and from the non-institutional groups such as the Tree Crops Society. Either individually or collectively they will collect, import, select, and develop horticultural crops which they will champion. Only when an individual crop can be demonstrated to have commercial success will the Government research scientists be in a position to lend their considerable expertise to further improvement. New Zealand will continue to have an international reputation for producing a diverse range of new and exciting horticultural crops. New apples and kiwifruit, diverse and colorful plants and flowers, and exotic fruits sourced from South America will be traded successfully in world fruit markets during future decades.

REFERENCES

Last update April 2, 1997 aw