Dix kg furent encore recoltes durant l'hiver 1998. Une truffiere toute proche, et celles dans le reste du pays, n'ont encore pro- dui! aucune truffe T melanosporum.
Actes du
ve Congres International
SCIENCE ET CULTURE DE LA TRUFFE ET DES AUTRES CHAMPIGNONS HYPOGES COMESTIBLES 4 au 6 mars 1999 • Aix-en-Provence • France
FRAN~AISE DES TRUFFICULTEURS
A COMPARISON OF PRODUCTIVE AND NON-PRODUCTIVE CULTIVATED TUBER MELANOSPORUMTRUFFLE BEDS . . IN NEW ZEALAND ?D*H · ·; iV .:ttfifi¥xf" "t!Witfir1ti'i¥Z':tfg'tMC(}Mo¥ ffitifi's :·#&i-Ut"itM ·z ?
Most edible ectomycorrhizal mushrooms of commerce are only available fresh in the Northern Hemisphere for short periods when they fruit. Consequently, there is a golden opportunity to produce them in Southern Hemisphere countries such as New Zealand to satisfy out-of-season demand in Northern Hemisphere markets.
HALL lan Robert; WANG Yun New Zealand Institute for Crop & Food Research Limited . lnvermay Agricultural Centre, Private Bag 50034 , Mosgiel, New Zealand
RESUME
----····-·-··-··----------······--·--··-·---·............--·-····--
Comparaison de truffieres cultivees en Tuber melanosporum, productives et non productives en Nouvelle Zelande Les premiers essais de production de truffes de Tuber melanosporum dans I'Hemisph€ne Sud pour le marche hors saison furent installes dans les annees 80. 11 y a maintenant plus de 50 truffieres experimentales en Nouvelle Zelande sur un ample assortiment de sots , avec peu ou pas du tout de champignons a ectomycorhizes, et dans des regions climatiques variees depuis Northland (36E S) a Alexandra (46E S). Les premieres truffes furent recoltees en juillet 1993, cinq ans apres avoir ete plantees a Gisborne (38.5E S). Malgre la concurrence intense de Scleroderma sp., T maculatum et une espece de Tuber, 0.5 ha de truffiere produisirent 9 kg de T melanosporum entre mai et le debut de septembre 1997, doni la plupart pesaient entre 250 et 750 g. Dix kg furent encore recoltes durant l'hiver 1998. Une truffiere toute proche, et celles dans le reste du pays , n'ont encore produi! aucune truffe T melanosporum. Une comparaison de ces truffieres pourrait nous donner un aperc;:u precieux des elements qui affectent le developpement de !'infection et de la fructification de T melanosporum.
--------·--- - - - ---------- - - - - - ABSTRACT
The first attempts to produce Tuber melanosporum truffles in the Southern Hemisphere for out-of-season Northern Hemisphere markets began in New Zealand in the mid 1980s. There are now more than 50 experimental truffieres in New Zealand on a wide range of soils with no or few competing ectomycorrhizal fungi and in varying climatic zones between Northland (36ES) and Alexandra (46ES). The first truffles were harvested in July 1993 five years after planting near Gisborne (38.5ES). Despite considerable competition from Scleroderma sp. , T macu!atum and a Tuber sp., between May and early September 1997 the 0.5 ha truffiere yielded 9 kg of T melanosporum truffles with many weighing between 250 g and 750 g. A further 10 kg were harvested in winter 1998. A truffiere nearby and those in other parts of the country have not yet produced any T melanosporum truffles. A comparison of these truffieres should provide valuable insights into factors that affect the development of T melanosporum infections and those that influence fruiting.
. KEYWORDS Tuber melanosporum, Perigord black truffle , cultivation, New Zealand --
- ·- -· .
More than a decade has passed since we presented our first paper at an international truffle conference on our attempts to cultivate T melanosporum in New Zealand (Hall 1989). Since then more than 50 truffieres have been established in New Zealand. Some of these have been established in areas which in; European experience would be considered close to ideal, while others are on soils or with climates very different from those in France , Italy and Spain. One of these truffieres has now begun producing T melanosporum truffles in commercial quantities whilst others have not. Comparing the conditions and management of this productive truffiere with those of other nonproductive truffieres provides insights into factors that can affect production. - - - -- -- -
. MATERIALS AND METHODS . Host plants
lt was decided to use Quercus robur and Gory/us avellana as the host plants because seed is readily available and these species grow well throughout New Zealand. Seed of other species such as Q. pubescens and Ostrya carpinifolia is difficult to obtain. At the start of research seedlings were raised from seed collected from plants of varying ages and locations. The seedlings were infected by our own modification of sporal inoculation techniques developed in the 1960s and 1970s by French and Italian workers (Chevalier & Dupre 1990; Fontana 1967; Patenzona 1969). This ensured a wide genetic base for both the fungus and host plant. Locations of truffieres Since 1987 infected plants have been offered for sale to landowners on high pH soils in areas with suitable climates. Plants have also been sold to those who own land in areas with suitable climates but where the soil has been heavily limed to raise the pH above 7.5. There are now more than 50 experimental truffieres between Northland (36ES) at the northern end of the North Island and Central Otago (46ES) which is towards the southern end of the South Island. Details on six of the older truffieres are presented in Table 1. Planting and maintenance Procedures used during planting and maintenance of the tru ffieres were similar to those used in Europe and are well covered in our two books (Hall et al.1994; Hall et al. 1998) and in two popular articles (Hall 1998; Zambonelli & Hall 1997). Growers, for example, were advised to irrigate the plants during periods of drought, till the soil carefully once in spring , and prune the trees to an inverted cone shape. However, these instructions ·:~ere not always followed.
~ RESULTS
- -- - -
INTRODUCTION
All of the main edible ectomycorrhizal mushrooms of commerce are natives of the Northern Hemisphere. Only a few of these such as porcini (Boletus edulis), saffron milk cap (Lactarius deliciosus), shoro (Rhizopogon rubescens) and some Tuber spp. have made the accidental journey to the Southern Hemisphere. This probably occurred on the roots of small deciduous trees that some of the early European settlers of Australia, New Zealand and South Africa carried with them as reminders of their land of birth .
AND DISCUSSION
The first T melanosporum truffles were harvested in late July 1993 some five years after planting on Oakland truffie re at Waerenga-a-hika near Gisborne on the east coast of the ~Jorth Island (39ES- Table 1). Small numbers were again harvested in the following two years in late July and August. Disaster ~hen appeared to have struck when Scleroderma, T maculatum and an unidentified species of Tuber seemed to have ousted T mela· nosporum. An alternative management regime was imple rn en· led in spring 1996 in an attempt to make the conditions in this truffiere more suited to T melanosporum. The ground was a.era4
.
TRUFFIERE Waerenga-a-hika Gisborne
Ohiwa
Ellmers Road Gisborne
Nelson
North Canterbury
North Otago
1993 to present
No
No
No
No
No
Extensive
Little
Little
Extensive
Extensive
Variable
Established
1988
1991
1988
1989
1988
1988
Latitude ES
39
39
38
41
43
45
18.3
18.3
19.1
17.2
17.5
16.4
Production Br(Jie
Mean January temperature EC Mean July temperature EC Accumulated degree days above 10EC
9
9
9.3
6.5
6.5
4.9
1430
1430
c. 1623
1038
1049
c. 900
Rainfall mm
1058
1058
1440
986
729
522
Annual sunshine hours
2172
2172
e. 2329
2397
1999
2095
Sunshine hours October- March
1283
1283
c. 1315
1377
1175
1221
Silt loam
Silt loam
Volcanic
Heavy clay
Rendzina
Rendzina
6.9
7.3
6.7
6.0
7.0-7.9
6.9-8.1
Soil type Natural soil pH After liming Irrigation
7.9
7.4
7.9
7.8
7.8
7.8
When needed
Little
When needed
Irregular
When needed
Irregular
In spring
Irregular
In spring
In spring
In spring
Irregular
Windbreak
Around truffiene
None
Surrounding trees
Surrounding trees
Plastic tubes
Around truffiere
Competing fungi
Scleroderma ... Scleroderma • • • Tuber spp." T maculatum ...
Scleroderma •
Scleroderma • Hebeloma · Others •
Scleroderma •
Scleroderma • Melanogaster •
Low soil phosphorus
High phosphorus
Soil aeration
Other potential problems
Table 1: Details of a productive and some non-productive New Zealand truffieres.
ted once in spring 1996 and trees were heavily pruned in September to allow additional light to reach the soil surface. This was successful because between May and early September 1997 the 0.5 ha truffiere yielded 9 kg of T melanosporum truffles with a further 10 kg harvested in 1998. Because many of the truffles weighed between 250 g and 750 g and were in excellent condition, we are confident that yields will continue to increase over the next 10 to 20 years even though the conditions in this truffiere are rather different from those in the majority of European truffieres. We also believe that there is now considerable commercial potential for growing T melanosporum truffles in additional truffieres on the extensive Waipaoa silt loams both around Gisborne in Poverty Bay and in northern Hawkes Bay about 100 km to the south. Although brules and good T melanosporum infections are present in all of the six truffieres truffles have been harvested only at Waerenga-a-hika. The reasons for this are almost certainly different for each of the truffieres. At the Ellmers Road truffiere (Table 1 and Map 1) which is only 2 km from Waerenga-a-hika and is on the same soil type, a lack of irrigation water at critical times has forced the main roots to grow steeply downwards and
has severely limited root and mycelial growth in the topsoil. We attribute the lack of truffles in the Nelson, North Canterbury and North Otago truffieres to dry conditions and relatively low summer temperatures while in the Ohiwa truffiere a poor soil structure and a low phosphorus status appears to be responsible for the problem. A more detailed study of the climatic and edaphic conditions in these and other truffieres is planned for the next 3 years. This will provide us with guidelines of where T melanosporum may be grown commercially in New Zealand outside the Gisborne region and a better understanding of the factors that trigger fruiting. The six experimental truffieres referred to in this paper and other younger truffieres elsewhere in New Zealand provide a unique opportunity for studying the development of T melanosporum infections on the host and factors that trigger fruiting in a wide range of soils and climates (Table 1) with no, or only a few, competing ectomycorrhizal fungi. The information that such research would provide will have significant implications not only for the truffle industry in New Zealand but in the Northern Hemisphere as well .
BIBLIOGRAPHY CHEVALIER , G .; DUPRE, C . 1990. Recherche et experimentation sur la truffe et la trufficulture en Fra nce. In: Be ncivenga, M .; Granetti. B . eds. Atti del Secondo Congresso lnternazionale sui tartufo. Spoleto. pp. 157-166.
HALL, I.R. ; BROWN, G.; BYARS, J. 1994. The black truffle: its history, uses and cultivation . 2nd ed. New Zealand Institute for Crop & Food Research Limited, Christchurch, New Zealand.
FONT ANA . A . 1967. Sintesi micorrizica tra Pinus s trobus e Tuber macula turn. Giorn. Bot. !ta l. 101: 298-299.
HALL, I.R.; BUCHANAN, P.; WANG, Y.; COLE , A .L .J. 1998. Edible and poisonous mushrooms: an introduction. New Zea la nd Institute for Crop & Food Resea rch Limited , Christchurch, New Zeala nd.
HALL. I.R . 1989. Towa rds a truffle industry in New Zealand. In: Proceedings of the second international congress on truffles (Spoleto, Italy. November 24 -27), 633-638.
PALENZONA, M . 1969. Sintesi micorrizica tra Tuber aestivum Vitt. , Tuber brumale Vitt. , Tuber me/anosporum Vitl. e semenzali di GoryIus avellana L. Allionia 15 : 121 -131 .
HALL. I.R. 1998. Nouvelle Zelande: Le programme de recherches truffieres . Le Trufficulteur Franr;ais 23 (2): 23-24.
ZAMBONELLI, A.; HALL, I.R. 1997. Tartufo. come "imparare" dalla Nuova Zelanda. Terre e Vi/a 48: 57-58.
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