The Nordic Gene Bank’s Prunus clone archive in Finland I Local races of sour cherry Pauliina Palonen Department ofPlant Production, PO Box 27, FIN-00014 University ofHelsinki, Finland, e-mail: pauliina.palonen@helsinki.fi Marjatta Uosukainen Agricultural Research Centre ofFinland, Laukaa Research and Elite Plant Station, Antinniementie I, FIN-41330 Vihtavuori, Finland Eeva Laurinen Agricultural Research Centre of Finland, Horticulture, Toivonlinnantie 518, FIN-21500 Piikkiö, Finland Päivi Parikka Agricultural Research Centre ofFinland, Plant Protection, FIN-31600 Jokioinen. Finland Jyri Kankila Department ofPlant Biology, PO Box 27, FIN-00014 University ofHelsinki. Finland Morphological variation among 78 local races of sour cherry (Prunus cerasus L.) in the Nordic Gene Bank’s Prunus clone archive in Pälkäne in Southwestern Finland was examined. Each tree was de- scribed using 42 characteristics. On the basis of fruit characteristics, 32 samples were classified as morellos, 40 samples as amarelles, and 5 samples distinct from the other amarelles are proposed to be called Rymättylä-type cherries. One sample was found to be Prunus avium. Amarelle type cherries proved to be more self compatible than morello type cherries. In order to find hardy sour cherry cultivars with fruits of good flavour and fit for cultivation in Nordic conditions, the most promising local races from each group were selected for a comparative trial. Additionally, some local races were selected for further use in plant breeding. In 1994-1996, an increasing amount of severe bacterial canker symptoms was observed in the clone achive. Key words', amarelle, morello, Prunus cerasus, Rymättylä, self-compatibility ntroduction able agricultural and horticultural plant materi- al in the Nordic countries. The horticultural crops are mainly vegetatively propagated, and must, therefore, be preserved on their original grow- ing sites (in situ), or in Gene Bank clone archives The Nordic GeneBank (NGB), founded in 1979, records and preserves genetic variation in valu- © Agricultural and Food Science inFinland Manuscript received June 1997 391 Vol 7(1998): 391- AGRICULTURAL AND FOOD SCIENCE IN FINLAND Palonen, P. et al. Prunus clone archive in Finland: sour cherry (ex situ ) (Trajkovski et al. 1992). The aim of the Prunus project of the Nordic Gene Bank is to find sour cherry, plum and damson plum culti- vars adapted to Nordic conditions, and to find local races, which could be cultivated as such, or used in breeding. Besides being used in fruit production, cherry, plum and damson plum trees are also excellent ornamentals. Sour cherry (Prunus cerasus L.) has been cultivated in Finland since the 17th century (Col- lan 1929). In 1929, after an exceptionally hard winter, it was found that in total 21 cherry culti- vars existed in Finland (Collan 1934). In the past, cherry trees were imported to Finland from Rus- sia, Estonia, Germany and Sweden (Collan 1929).The oldestknown cultivars in Finland are ‘Yleinen kuulasmarja’ (‘Common amarelle’), ‘lso kuulasmarja’ (‘Big amarelle’) and ‘Varjo- morelli’ (known as ‘Schattenmorelle’ in Germa- ny and ‘Skuggmorell’ in Sweden) (Meurman 1947).The trees have been open pollinated free- ly, and new offspring generated from seeds have been propagated and distributed through root suckers. Due to the decades of long natural se- lection and adaptation to harsh conditions, the hardiest germplasm available is most probably to be found among the native cultivars. An understanding of phenotypic and genetic variation in sour cherry is important for cultivar development, future germplasm collection, and setting of priorities for germplasm maintenance (Hillig and lezzoni 1988). The objective of this study was to examine the morphological varia- tion in local races of sour cherry in the Nordic Gene Bank’s Prunus clone archive at the Agri- cultural Research Centre ofFinland, Häme Re- search Station in Pälkäne, and to select the most promising local races for a comparative trial, starting in 1994. Material and methods The local races of sour cherry, plum and dam- son plum were registered during 1982-85, main- ly in Southern and Southeastern Finland includ- ing the Åland Islands. From every individual Prunus tree, registered on the Finnish mainland, at least two root suckers were taken and trans- ported to the Agricultural Research Centre of Finland, Institute of Horticulture in Piikkiö, where they were planted in a temporary loca- tion. In 1988, duplicates of each local race were sent to Pälkäne (61 °2o’ N, 24° 13’ E), where trees were planted on an experimental field with sandy soil at a spacing of 3 metres withinand 4 metres between rows. The local races originating in the Åland Islands were placed in a Prunus clone ar- chive at Åland Experiment Station in Jomala. In Pälkäne, disease symptoms were observed, but no plant protection chemicals were used in the Prunus orchard. 300 kg of compound ferti- lizer (NPK 7-5-15) per hectare was applied an- nually. Every tree was protected against mead- ow voles with a plastic shield. Weeding was car- ried out by mowing or harrowing, when needed. Root suckers were removed annually. The trees were not pruned. Documentation of cherry material in the Pru- nus clone archive in Pälkäne was carried out during each season between 1992 and 1993. In 1992, the Prunus clone archive consisted of 122 sour cherry trees, representing 79 different lo- cal races, and in 1993, of 118 trees, represent- ing 78 different local races. Each tree was de- scribed by the characteristics used by the Nor- dic Gene Bank. The descriptions were comple- mented with some further characteristics used by the International Union for the Protection of New Varieties ofPlants (UPOV). In total 42 char- acteristics were used for the description of each tree. Characteristics observed were related to growth habit, flowering, fruit set, as well as the external and internal properties of the fruits. The descriptions were made mainly in 1992 and com- plemented in 1993. The descriptions will be saved in the Nordic Gene Bank’s database BIRS. In 1992 and 1993, the self-compatibility of local races of sour cherry was studied. In 1992, 30 local races were selected for the self-com- patibility studies. Three branches per tree were isolated before floral anthesis by enclosing them 392 AGRICULTURAL AND FOOD SCIENCE IN FINLAND in acrylic bags. Additionally, some branches were collected from each tree, and forced to flower. Pollen was collected and the isolated flowers were self-pollinated. Also, threebranch- es per tree were marked and allowed to open pollinate. In 1993, the pollination experiments were limited to 20 local races selected in the previous year. Two branches per tree were isolated with acrylic bags, and two branches were marked and used as open pollinated controls. Self-pollina- tion was aided by brushing the isolated flowers carefully with a small clean brush, as the pollen was dehisced. This was carried out daily during the flowering period. The number ofself-pollinated flowers and the number of open-pollinated flowers were count- ed, and in early July, the number of green fruits was recorded. The percentages of fruit set on self-pollinated and on open pollinated branches were calculated. The self-compatibility compar- isons were made in two different ways; based on the geographic origin of the local races, and based on their fruit type classification. The self- compatibility of Eastern and Western local races was compared in 1992, and the self-compatibil- ity of local races, belonging to different main groups, in 1993.The ratio ofpercentage fruit set with self-pollination to that with open pollina- tion describes the self-compatibility of each lo- cal race. The data on the ratios were analysed with ANOVA- 1-test of MSTAT-C -program (Michigan State University 1989). All the local races of sour cherry were eval- uated for their possible further use. The main criteria were: ornamental value, fruit set, fruit quality, winter-hardiness and resistance to dis- eases and pests. Each local race was either rec- ommended for further study or determined to be of no value. In order to find hardy sour cherry cultivars with fruits of good flavour and fit for cultivation in Nordic conditions, the most prom- ising local races from each group were selected for a comparative trial and some for possible further use in plant breeding. Results Although trees flowered freely in 1992, the yield was low, and the harvesting period was length- ened because of the cool weather. In 1993, the flowering season was very early because of the extremely warm weather in May and the period of flowering varied from 12May to 29 May. The differences in earliness of flowering were negli- gible among the clones. On average, the yield was very high and the fruits were of good qual- ity. The fruits were harvested from 28 July to 13 August. On the basis of their fruit characteristics the local races of sour cherry were classified into three main groups (Table 1). One local race was found to be Prunus avium. Group 1. Morello cherries. Fruits are very dark, nearly black when mature. The mean weight of the fruits was 2.4 g in 1993. The stalk is fairly long. Fruit flesh and juice are dark red. The cherries are very aromatic but mostly ex- tremely bitter. The trees have long and weak branches, with bare parts on them. Because of their high content of acids, intense juice colour and strong aroma, the fruits are suitable for con- serving and for use in the food processing in- dustry. Group 2. Amarelle cherries. Fruit colour is red or dark red. The mean weight of the fruits was 2.5 g in 1993. The stalk is ofmedium length. Fruit flesh is yellowish pink and juice is colour- less or pink. At maturity, the fruit skin is often nearly translucent. The cherries are relatively sweet or slightly bitter, and less aromatic than morellos. The fruits are suitable for fresh con- sumption. The trees may be big and bush-like or small with a decorative form. Group 3. Rymättylä-type cherries. The sour cherry races of this group resemble amarelle cherries, except that the fruits tend to be bigger and flatter. The stalk is typically short, thick and rather stiff. The mean weight of the fruits was 2.8 g in 1993. Fruit colour is red. The cherries are proposed to be called Rymättylä-type, as they have been registered in Rymättylä or its sur- 393 Vol. 7(1998): 391-399. AGRICULTURAL AND FOOD SCIENCE IN FINLAND Palonen, P. et al. Prunus clone archive in Finland: sour cherry Table I. Local races of sour cherry, selected for further study. The races are divided into the three main groups of the Finnish sour cherry. Morello cherries Amarelle cherries Rymättylä type 7 Rymättylä Myttäälän hapankirsikka 4 Rymättylä 35 Parainen 12 Tammela 5 Rymättylä 87 Laukaa 19 Somero 10? 107 Mäntsälä 24 Masku 37 Turku 110 Virojoki 30 Tenhola 66 Sammatti 112 Vehkalahti 43 Kustavi 114 Lappeenranta 52 Tuusula 116 Joutseno 54 Vantaa 121 Juva 74 e, Lohja mlk 122 Juva 85? 123 Juva 86? 125 Pertunmaa 91 Nurmijärvi 129Anjalankoski 92 Loppi 134 Pertunmaa 93 Kärkölä 141 Anttola 95 Hollola 142 Puumala 96 Hollola 98 Asikkala 101 Kuusankoski 102 Koria 104 Kotka 105Lapinjärvi 108 Mäntsälä 109 Pyhtää 124 Mikkeli mlk. 131 Lahti 133 Pertunmaa 137 Laukaa 139 Toivakka 140 Kangasniemi 143 Anttola 144, Anttola 146 Joroinen 160 Mikkeli mlk. 301 ? roundings in Southwestern Finland. Their ori- gins are not known. The local races of morello cherries were found growing mainly in Eastern Finland. The distribution of local races of amarelle cherries is more western. These two types meet each other in the area between 26° and 21° of eastern lon- gitude. In the clone archive, the most northern samples of both types were found growing in Laukaa (62°20’ N). However, after the NGB col- lection was completed in 1988, two more sam- pies were registered even further north. The most northern morello sample was found from Tuus- niemi (62°45’ N) (R. Teravuo, personal commu- nication, 1993), and the most northern amarelle sample from Pihtipudas (63° 15’ N) (M. Raatikai- nen, personal communication, 1992). These two samples were added to the clone archive in 1995. In 1992, the percentage of fruit set varied with self-pollination from 0 to 18, the average being 4.3, and with open pollination from 3 to 24, the average being 10.7 (Table 2 and Fig- 394 AGRICULTURAL AND FOOD SCIENCE IN FINLAND ure 1). It was found that the local races from Western Finland yielded higher percentages of fruit set, both by self-pollination and by open pollination, than the local races from Eastern Table 2. Percentage fruit sets of sour cherry by self-polli- nation (self) and by open pollination (open) in 1992 and 1993, and theirratio in 1993, Percentage fruit set Local 1992 1993 self/open self open self open (%)race no. Morellos 1.3 14.1 5.2 34.3 15.5 Amarelles 4.9 9.1 23.1 27.4 94.3 Rymättylä-type 10.5 10.5 38.5 38.5 102.0 Total average 4.3 10.7 19.3 30.6 71.4 Finland. Because of highly random variation in the results it is impossible to say which local races are self-compatible (Saarimäki 1994). In general, the percentage fruit sets were in 1993 higher than in 1992. They varied with self-polli- nation from 2 to 39, the average being 19.3, and with openpollination from 13to 43, the average being 30.6. Amarelle cherries and Rymättylä- type cherries proved to be more self compatible than morello cherries (P=0.001). Local races recommended for further study are indicated in Table 1 and the local races se- lected for a comparative trial are presented in Table 3. Both Tuusniemi and Pihtipudas local races, which were added to the clone archive in 1995, were also selected for a comparative trial. Additionally, some local races were selected for further use in plant breeding (Table 4). Fig I. Self-compatibility of local sour cherry races in different main groups presented as percentage fruit set by self-pollination and open pollination in 1992 and 1993. Within each group, local races are in geographical order from west to east. 395 Vol. 7(1998): 391-399. AGRICULTURAL AND FOOD SCIENCE IN FINLAND Palonen, P. et al. Prunus clone archive in Finland: sour cherry Table 3. Local races of sour cherry selected for a comparative trial. No. Origin Season of Fruit set*' Season of Form **' Weight Colour Stalk Pit % Soluble flowering 1-9 ripening 1-5 g 1-9 mm solids% Morellos 7 Rymättylä medium 7 late I 2.7 8-9 35 11.1 14.7 122 Juva medium 7 late I 2.7 8-9 40 10.0 14.8 Amarelles 24 Masku early 7 early 1-2 2.3 6 30 7.9 17.5 85 ? early 9 early 2 3.1 5 30 7.1 14.2 91 Nurmijärvi early 7 early 1 2.4 5 35 8.8 16.4 93 Kärkölä medium 7 medium 1-2 2.8 6 35 7.1 14.4 96 Hollola late 9 med.-late 2 2.6 1 29 8.8 11.9 101 Kuusankoski medium 9 medium 1-2 2.5 4 35 10.0 13.7 104 Kotka medium 8 medium 2 2.8 4 30 7.6 13.2 109 Pyhtää medium 9 medium 1-2 2.5 4 35 10.0 13.2 137 Laukaa medium 8 medium 1 2.6 6-7 30 8.1 15.1 301 ? early 8 early 2 2.3 7 30 9.8 15.0 Rymättylä-type 10 Rymättylä early 9 medium 2 2.6 4 25 7.7 13.2 37 Turku early 9 medium 2 2.6 5 25 7.5 15.0 *' Fruit set ranges from Ito 9, 1=no fruit set, 9 = very high yielding **' Form: 1 =kidney, 2 = flat-round, 3 = round, 4 = elongated, 5 = heart *" ) Colour ranges from 1 to 9, 1 being the most light-coloured (bright red) and 9 being the darkest (black red). During the documentation period no pests were detected. However, brown rot ( Moniliasp.) destroyed some sour cherry fruits and in 1994, bacterial canker (Pseudomonas sp.) symptoms were observed in some trees. In 1995 and 1996, symptoms, including leaf necroses, shoot die- back and even dying of individual trees, had spread throughout P. cerasus material. Symp- toms indicated eitherPseudomonas syringae pv. syringae or P. s. pv. morsprunorum infection (Bech 1992, Sobiczewski and Jones 1992). The identification of these pathogens has so far not been succesful. Discussion Evaluation of sour cherry fruits is greatly affect- ed by their degree of maturity. The optimumrip- ening date is difficult to assess visually, as sour cherries reach full maturity up to two weeks af- ter they seem to be mature, based on fruit col- Table 4. Local races of sour cherry selected for further use in plant breeding, and the special properties of each. No. Origin Special properties 66 Sammatti Fruit set is very high. The fruits are big but tasteless and sour. 139 Toivakka The tree is very decorative, both in flowering and at harvest. Fruit set is high, but the fruits are small and without flavour. 144 Anttola The fruits are big, sweet and have an exceptionally good aroma. Fruit set is poor. 146 Joroinen The fruits are rather sweet and well tasting. Fruit set is poor. 158 Imatra The only Prunus avium in the clone archive. The fruits are small and sweet. Fruit set is poor. 396 AGRICULTURAL AND FOOD SCIENCE IN FINLAND our. During this time many of their properties, such as taste, aroma, content of soluble solids and even fruit size continue to change signifi- cantly (Nyman 1990). Because of wide genetic variation, differences between the three sour cherry groups in the clone archive are not distinct. Diversity is continuous, and a lot of variation occurs within each group. This is due to the fact that, historically, new prog- enies have arisen from seeds, and have been spread through propagating root suckers. A clear difference in geographical distribution between morellos and amarelles in Finland was observed, morelles being ofeastern and amarelles of west- ern origin. This most likely reflects their differ- ent ways of entry into the country, and is in agreement with findings of Kolesnikova (1975) (Ref. lezzoni et al. 1990), who divided sour cher- ry cultivars into two ecotypes based on morpho- logical differences and cold-hardiness: i.e. west- ern European and middle-Russian ecotypes. In Southern andWestern Europe amarelle type cher- ries have been favoured, while in Eastern and Northern Europe and Russia more cold hardy morello type cherries have been favoured (Yu- shev 1975, 1977, Ref. lezzoni et al. 1990). On the basis of our results from 1993, the morello type local races were regarded as partly self-compatible, their percent fruit set by self- pollination varying between 1.5 and 15 (Redalen 1984a). The small fruit size of most morellos in the Prunus clone archive is evidence of them being mainly forms of ‘Yleinen ruskeakirsikka’ (‘Common brown cherry’), which is self-incom- patible, and has been widely cultivated in Fin- land because of its hardiness (Collan 1929, 1934). The other common morello type cultivar is ‘Varjomorelli’. It is one of the oldest sour cher- ry cultivars in Finland and totally self-compati- ble (Meurman 1947, Nilsson 1989). Amarelle type local races in the clone archive proved to be self-compatible. They are supposed to be mainly forms of ‘Yleinen kuulasmarja’ (‘Common amarelle’), which has been widely cultivated in Finland, as far as the northern boundary of cherry cultivation (Collan 1929, Meurman 1947). In amarelle type local races, especially in Rymättylä type cherries, also some characteristics of Duke cherry cultivar ‘lso kuu- lasmarja’ (‘Big amarelle’) were observed. In comparison with sour cherries from other Nordic countries, native sour cherries in Finland have relatively small fruits. The fruit size is, however, greatly affected by growing conditions. In our study, the mean weight of fruits was 2.4 g for morellos, 2.5 g for amarelles and 2.8 g for Rymättylä type cherries. In a cultivar trial in Sweden, the average fruit weight of sour cherry cultivars was 4.7 g (Hintze 1976). In Denmark the average fruit weight was 4.3 g for morello cultivars, and 4.6 g for amarelle cultivars (Chris- tensen 1990), and in Norway 4.08 g and 4.32 g for morellos and amarelles, respectively (Vestr- heim 1986). Based on the results of this study, native morello type cherries in Finland are less self- compatible than morello cultivars in Norway. In contrast, the Finnish amarelle type cherries are more self compatible than those in Norway. For morellos, the average percents fruit set by self- pollination were in our study 1.3, and 5.2, in 1992 and 1993, respectively, and in Norway it was 14.7 (Redalen 1984b). The average percents final fruit set by self-pollination were for am- arelles 4.9 and 23.1, in 1992 and in 1993, re- spectively. For Norwegian amarelle cultivars it was 5.0. The average content of soluble solids in local races selected for a comparative trial was 14.5%. It is equal to the threshold value deter- mined by Vangdal (1980) for sweet cherries. In regard to its annual growth rhythm, sour cherry is a potential new fruit crop in Finland. The cherries ripen early enough, and can thus be cultivated also further north, if only winter hardiness is secured. In order to find new com- mercial sour cherry cultivars adapted to Nordic conditions, the most promising local races from each group were selected for a comparative tri- al. The aim is to select a few cultivars suitable for fresh fruit production, home gardens and even for industrial production. For example, in Den- mark, where sour cherry is the largest fruit crop next to apple, the production has mostly been concentrated on clones of local seedlings, the 397 Vol. 7(1998): 391-399. AGRICULTURAL AND FOOD SCIENCE IN FINLAND Palonen, P. et al. Prunus clone archive in Finland: sour cherry most important of thembeing ‘Stevnsbär’ (Chris- tensen 1990). Through micro-propagation it is possible to produce own-rooted sour cherry trees. The advantage of this is that own-rooted trees are capable of regrowth even after severe win- ters, when the trunk of the tree is damaged or died. Acknowledgments.Financial support from the Nordic Gene Bank is greatfully acknowledged. References Bech, K. 1992. Susceptibility to bacterial canker in sour cherry varieties. Orchard observations and inocula- tion trials. Journal of Phytopathology 134: 238-246. Collan, 0.1929. Hedelmän- Ja marjanvitjetyksen käsikir- ja. Otava. Helsinki. 424 p. - 1934. Suomen hedelmänviljelys hedelmätarhojamme v. 1929 kohdanneen tuhon valossa. Valtion maata- louskoetoiminnan julkaisuja no. 60, Helsinki. 68 p. Christensen, J. V. 1990. A review of an evaluation of 95 cultivars of sour cherry. Tidskrift for planteavl(Dan- ish Journal of Plant and Soil Science) 94: 51-63. Hillig, K. W. & lezzoni, A. F. 1988. Multivariate analysis of sour cherrygermplasm collection. Journalof Amer- ican Society ofHorticultural Science 113; 928-934, Hintze, S. 1976. Sortförsök med surkörsbär. Konsulent- avdelningens stencilserie. Trädgård 103. Sveriges Lantbrukshögskolan.Alnarp. lezzoni, A., Schmidt, H. & Albertini, A. 1990. Cherries (Prunus). Acta Horticulturae 290: 111-173. Kolesnikova, A. F. 1975. Breeding and some biological characteristics of sour cherry in Central Russia, Orel, U.S.S.R.: Priokstoc IzdateTstvo. (Ref. lezzoni et al. 1990). Meurman, O. 1947. Suomen hedelmäpuut Ja viljellyt marjat. Il Päärynät, luumut, kirsikat Ja marjat. Oy Suomen Kirja. Helsinki. 351 p. Michigan State University. 1989. User's guide to MSTAT-C. Michigan. Nilsson, A. 1989. Våra päron-, plommon- och körsbär- sorter. Nordiska Genbanken. Örebro. 370 p. Nyman, I. 1990. Hapan ja imelä kirsikka. In: Suomalain- en puutarha. Marjat ja hedelmät. Weilin + Göös. p. 238-247. Redalen, G. 1984a. Fertility in sour cherries. Gartenbau- wissenschaft 49: 212-217. -1984b. Pollinering av plomme og surkirsebaer. Gartneryrket 74: 446-350, Saarimäki, S. 1994. Pölyttyminen hapankirsikan (Prunus cerasus L.) hedelmänmuodostuksessa. Master’s the- sis. Horticulture. Department of Plant Production. University of Helsinki. 43 p. Sobiczewski, P. & Jones, A, L. 1992. Effect of exposure to freezing temperatures on nekrosis in sweet cher- ry shoots inoculated with Pseudomonas syringae pv. syringae or P, s. pv, morsprunorum. Plant Disease 76: 447-451. Trajkovski, V., Fernqvist, 1., Bjurman, 8,-O. & Rumpunen, K. 1992. Genetiska resurser hos nytto- och prydnads- växter. (Summary: Genetic resources in horticulture.) Balsgård - Institutionen för hortikulturell växtför- ädling. Verksamhetsberättelse 1990-1991.Sveriges Lantbruksuniversitet. Alnarp. p. 132-139. Vangdal, E. 1980. Threshold values of soluble solids in fruit determined tor fresh fruit market. Acta Agricul- ture Scandinavia 30: 445-448, Vestrheim, S. 1986. Forsok med 11 surkirsebsersortar. (Summary: Trial of 11 sour cherry varieties). Institut! for fruktdyrkning, Melding nr. 116. Meldingar fra Nor- ges Landbrukhegskole 65: 11. Yussef, A. 1975. Morphological characters of the leaf in sourcherry and their use in the classification of vari- eties. Byulletin Vsesojusniy Ordena Lenina 54: 34- 40 (in Russian). (Ref. lezzoni et al. 1990). - 1977. Morphological characters of the fruit in sour cherry and their use in the classification of varieties. Byulletin Vsesojusniy Ordena Lenina 75: 27-31 (in Russian). (Ref. lezzoni et al, 1990). 398 AGRICULTURAL AND FOOD SCIENCE IN FINLAND SELOSTUS Pohjoismaisen geenipankin Prunus-kokoelma Suomessa I Hapankirsikkakannat Pauliina Palonen, Marjatta Uosukainen, Eeva Laurinen, Päivi Parikka ja Jyri Kankila Maatalouden tutkimuskeskus ja Helsingin yliopisto Maatalouden tutkimuskeskuksen Hämeen tutkimus- asemalla sijaitsevan Pohjoismaisen geenipankin Pru- m/s-kokoelman hapankirsikkakannoissa (Prunus ce- rasus L.) esiintyvää geneettistä muuntelua kartoitet- tiin arvioimalla kantojen morfologisia ominaisuuksia. Vuonna 1993 oli elossa 118 kirsikkapuuta, jotka edustivat 78 eri paikalliskantaa. Jokaisesta puusta laa- dittiin 42 ominaisuutta sisältävä kuvaus, joka tallen- nettiin Pohjoismaisen geenipankin BIRS-tietokan- taan. Perinnöllistä vaihtelua esiintyi runsaasti, Ominai- suuksiensa perusteella kirsikkakannat jaettiin kol- meen ryhmään. 32 kantaa oli pääasiassa itäsuomalais- ta alkuperää olevia morelleja, joiden hedelmämehu on tummanpunaista. 40 kantaa oli kuulasmarjatyyppisiä, joiden hedelmämehu on vaaleaa. Kuulasmarjat oli kerätty pääasiassa eteläisimmästä Suomesta. Viisi Rymättylästä, Turusta ja Sammatista rekisteröityä kuulasmarjakantaa erosivat muista kuulasmarjoista, ja niille ehdotetaan annettavan nimeksi rymättylätyyp- piset hapankirsikat. Vain yksi kokoelman kannoista oli imeläkirsikka. Kuulasmarjat ja rymättylätyyppi- set hapankirsikat osoittautuivat itsepölytyskykyisik- si ja morellit osittain itsepölytyskykyisiksi. Kartoituksen yhteydessä kaikkien kirsikkakanto- jen mahdollinen käyttöarvo arvioitiin. Tärkeimpiä kriteereitä olivat puun koristearvo, satoisuus, sadon laatu, tauti- ja tuholaiskestävyys ja talvenkestävyys. Lupaavimmat kirsikkakannat valittiin kantavertailu- kokeeseen, jonka tavoitteena oli löytää Suomen oloi- hin soveltuvia lajikkeita. Lisäksi joitakin kantoja va- littiin jonkin hyvän ominaisuutensa vuoksi käytettä- väksi jalostuksessa. Hapankirsikan käyttöä hedelmän- viljelyssä saattaa rajoittaa alttius Pseudomonas-syrin- gae pv. syringae ja P. s. pv, mor.sprwnorwm-baktee- reille. 399 Voi 7 (1998): 391-399. AGRICULTURAL AND FOOD SCIENCE IN FINLAND