The world's genetic diversity of wild fruit and small-fruit plants is comprised of 5,320 species representing 55 genera of 22 families. Out of this number only 818 spp. are utilized over the world.
One of the world's richest centres of diversity of wild fruit species is in the Caucasus: over 260 species of 37 genera occur in Caucasian forests. N.I. Vavilov regarded the Transcaucasian area as the major formation base of species and varieties for a number of wild fruit plants. In river valleys and on river banks there are extensive dogwood thickets and those of quince and myrobalan plum, and the underwood is formed of currant, raspberry and gooseberry which are very valuable for plant introduction in many areas of the country.
Fruit plants are widely distributed in Central Asia, but the diversity of their species and forms is not so rich as in the Caucasus. 212 fruit species of 33 genera can be found there, and their distribution over this area is not even. In the desert belt there are oleaster thickets without admixtures, in the foothill belts - almond and dwarf cherry, in the upland steppe zone pear-trees, apricot, etc. The richest area is the mountainous forest-steppe belt where all wild species can be found.
Siberia and the Far East are not so rich in fruit species, but possess quite a range of endemics promising for introduction and utilization in plant breeding for winter hardiness.
The main trend in the utilization of wild fruit and small-fruit plants, in addition to food and medicinal application, is hybridization .
In the past, fruit of wild small-fruit patches played a noticeable role in the diet of the country's population and were subject to exports. The first evidence of the export of berries was found in the governmental reports on foreign trade for 1817. At that time, their exports amounted to 3.5 million roubles, while the yield of wild fruit plants in the forests of the Russian Empire was estimated as 100 million roubles per year. Before the Second World War the organized purveyors collected annually 1.5 million tons of wild fruit and berries. No less important were the procurements made by the local population for their own consumption, but for all these purposes only 10-12% of the total yield were usedt23.
At present, forests cover more than 55% of the territory of the former USSR. Wild fruit, small-fruit and nut-bearing plants are distributed over the area of 57 million hectares and can annually yield 3 or 4 million tons of valuable food and vitaminic raw matter. However, only the same 10-12% of potential forest bioresources are now utilized, as it was in the past. For berries this quota is 4-5%.
By the degree of commercial utilization wild fruit resources may be divided into the genera of primary economic importance (sea buckthorn, dog rose, cowberry, whortleberry cranberry), those of secondary economic importance (dewberry, raspberry, mountain ash, gooseberry, currant), and those of predominantly local significance (viburnum, European birdcherry, wild strawberry).
Depending on the existing stock of wild fruit resources in the former USSR, they were subdivided into 5 groups. The first group included the stock sufficient for procurement of raw matter: Armeniaca vulgaris Juss. (common apricot), Cydonia oblonga Mill. (quince), Crataegus L. (hawthorn), Sorbus aucuparia L. (mountain ash), Rubus idaeus L. (red raspberry), Fragaria vesca (wild strawberry), Rubus caesins L. (dewberry), Corylus avellana L. (European filbert), Prunus spinosa L. (black thorn), Vaccinium myrtillus L. (whortleberry), Pyrus communis L. (common pear), Cerasus fruticosa (Pall.) G.Woron (steppe cherry), Rosa spp L. (dog rose), (birdcherry), Malus silvestris (crab apple), etc.. The second group was comprised of the stock insufficiently studied: Grossularia reclinata (L.) Mill. (European gooseberry), Berberis vulgaris (common barberry), Prunus mahaleb L. (mahaleb cherry), a number of Crataegus spp L. (hawthorn)., Amelanchier Med. (june-berry), Ribes alpinum L., R. pubescens (Schwartz.) Hedl., Malus spp Mill..), etc. The third group included the resources requiring limitations of harvest procurement and rehabilitation: Vaccinium vitis idaea L. (cowberry), blueberry, Crimean mountain ash, cranberry, European cranberry-bush, cornelian cherry, stone-berry. The fourth group required total prohibiting of procurements, protection and rehabilitation: whitebeam mountain ash, small cranberry. The fifth group covered the resources deserving wider domestication: stone-berry, cornelian cherry, black cotoneaster, all hazelnut species, silver hawthorn, medlar, golden currant, European cranberry-bush, honeysuckle, serviceberry, European birdcherry, etc.
The yield of wild fruit and small-fruit plants demonstrates considerable changes not only in different zones, but also in different phytocoenoses within one zone. For example, average yield of mountain ash fruits is 16-20 kg per 1 plant in oak groves, 5-10 kg/plant in mixed forests, and 3-5 kg/plant in pine woods; and the yield of European birdcherry amounts to 18-20 kg/plant in mixed old tree-stands, 8-12 kg/plant on oak-grove glades, and 6-7 kg/plant in brushwood.
Crab apple yields 80-120 kg per 1 tree on wood glades, 50-70 kg/tree in mixed forests, and up to 15-20 kg/tree in pure pinewoods. High yields (70-80 kg/plant) are produced by the plants growing in mixed forests on foothills.
Pear-trees yield fruit up to 70-100 kg/tree when growing in the glades of broad-leaved forests on flatland, 50-70 kg in old forests and foothill woods, up to 100 kg in shrub thickets, but only 10-15 kg/tree in pure pine forests.
Sour cherry yields 10-15 kg per 1 bush in the brushwood of broad-leaved forests on foothills, and 10-11 kg/tree on glades. Common hawthorn produces the most abundant fruit yields on glades in oak woods (5-6 kg) and oak-and-pine forests (4-5 kg). On low hills the yield is 2-3 kg per bush, and in the brushwood of flatland forests 3-4 kg/bush. In the most productive years, the yield per 1 bush amounts to 8-10 kg in open sites on the slopes of river terraces. The yield of black thorn reaches 10-15 kg in the years of total fruit bearing and falls down to 8 kg in other years.
Dewberry in damp places in some years may yield 1 ton of fruit per hectare or even more, but on mountainous plateaux the yield never exceeds 0.2-0.3 t/ha.
Whortleberry fruit yields in mountain forests may amount to 0.5-0.7 t/ha, but on flatlands under the cover of old tree stands they average 0.3-0.4 t/ha, and in the Sub-Alpine zone up to 0.2 t /ha .
Enhancement of production and variety of the released vitaminic and medicinal substances, ever widening utilization of wild-growing raw materials in food production and medicine - all this demands studying these resources under the geographic aspect, searching for high-yielding plant forms in the wild nature for further domestication, breeding new varieties on their basis, multiplying them, and setting new plantations in the most appropriate areas. This, however, does not exclude the need to study and better utilize the existing natural resources, restore the abandoned purveyance sites and develop new ones with strict observation of environmental protection measures.
Studying of plant resources in natural environments showed a certain regularity: the species which were widely distributed in nature, when some important substances needed by the industry and medicine were detected in them, shortly became rare due to intensive utilization of their thickets, and then even nearly vanished. Under the effect of drainage in the last 20-25 years the resources of bog cranberry have suffered abrupt reduction. As reported by the Research Institute of Forest Reclamation, land reclamation activities lead to 11-times decrease of cranberry yields.
In the last decade the areas of distribution of blueberry and red whortleberry have been shrinking, and the areas under bilberry resources are beginning to dwindle. One of the reasons of this phenomenon is unrestrained barbarous utilization of these resources by using various combs, scoops and other appliances for fruit collecting, after which the bilberries would not yield fruit for several years. It is necessary to set an unconditional veto on application, manufacturing, sale and use of such "tools for mechanized harvesting". Here a citation from Gerald Durrel. an outstanding British naturalist, would be to the point: "extermination of any species is a criminal act similar to destruction of unmatched monuments of culture, such as the works of Rembrandt or the Acropolis".
Of course, with rational utilization, many valuable plants may be utilized for a long time as the sources of natural raw matter, but the need to domesticate useful wild plants is expressly commanded by the age we are living in. This is ever more crucial for the regions with little forest but dense population.
The starting point for rational utilization of the natural stock of fruit and berry plants is to preserve the habitats most favourable for their growing, i.e. to ensure sufficiently stable functioning of corresponding ecosystems, which could be attained by establishing natural reserves and protected zones.
In the USSR there were 1,850 natural reserves of diverse purposes covering the area of more than 47,000 hectares. Specific nature of the natural reserves for plant genetic resources (PGR) lies in the possibility of limited economic activities providing for maintenance and even increasing of the stock of useful plants without disturbing natural ecosystems. PGR reserves may serve not only as a source of raw matter purveyance, but also as a base for studying the dynamics of plant resources, developing measures towards their preservation and multiplication with an aim of meeting the demands in such raw materials to the fullest extent.
In addition to the species of wild fruit and berry plants which have already been used by the national economy and which have undergone sufficient studying, there still are plant species unstudied and regions unexplored. The task having at this time the highest importance is to study, preserve and utilize them as the sources of food and medicinal raw materials and as the initial plants materials for breeding. Priority in studying and protection should be given in the former IJSSR's republics to 40 species of hawthorn, 9 spp. of strawberry, 40 spp. of service tree, 6 spp. of birdcherry, 15 spp. of barberry, 7 spp. of oleaster, 3 spp. of gooseberry, as well as june-berry, medlar and cornelian cherry.
In the mountains of the Caucasus there are yet unexplored thickets of wild sweet cherry, pear, apple, cornelian cherry, myrobalan plum and Persian walnut. Filbert, large-fruited forms of cornelian cherry, sea buckthorn and chestnut are available in the mountains of Western Georgia. There are numerous forms of myrobalan plum, blackthorn, cornelian cherry, pear, barberry, hawthorn, persimmon and sea buckthorn in Sheki Zakataly zone. In Siberia, worth studying are sea buckthorn thickets, large-fruited gooseberry forms resistant to fungi, and wild currants. 6 hawthorn species, sour cherry and cornelian cherry occur in Crimea. In the Far East, there are over 60 East Asian species of fruit and small fruit plants, including liana plants. Barberry, currant, Persian walnut, almond, apricot, sour cherry, hawthorn, strawberry, plum, blackberry, pear, service tree and oleaster occurring in Central Asia are of great interest for plant breeders. And if the genetic diversity first of all needs to be protected, the resources of such diversity should be efficiently and rationally utilized.
With the purpose of more comprehensive identification of the diversity of wild crop relatives and evaluation of their stock, VIR has accomplished extensive work in identifying the areas most rich in these species and subject to immediate profound research. Besides VIR has worked out proposals for the establishment of a network of natural reserves, protected zones and guarded natural boundaries.
It should be taken into account that the process of genetic erosion in plants is observed all over the world, therefore one of the major problems of the present day is to save the rich diversity of botanical species disregarding their economic significance, but guided in these efforts by "the global strategy for conservation of nature" set forth by IUCN (International Union for Conservation of Nature and Natural Resources).
In view of this, one of the most vital nature protection measures should be the inclusion of rare and vanishing species in the Red Book.
It has been already stated above that the former USSR houses rich genetic diversity of many small-fruit crops, for example 41 spp. of currant including 9 species threatened due to the very scanty stock available. Wild species, such as Ribes dicuscha Fisch., R. procumbens Pall., R. panciflorum Turcz. and others, in the size of fruit and nutritional qualities can be matched with many cultivated varieties. R. petiolare and R. graveolens are already used as donors to breed forms resistant to powdery mildew. For breeding high-yielding winter-hardy commercial cultivars of raspberry, especially valuable are such wild species as Rubus idaeus L., Far Eastern forms and R. komarovii Nakai.
The richest genetic diversity of wild apple-trees in concentrated in Central Asia. 60% of all apple-tree groves of the former USSR are situated in Kirghizia. Malus niedzwetzkyana Dieck. has been included in the Red Book and 5 more species are under protection. The widest diversity of pear is accumulated in the Caucasus and Central Asia. 3 pear species are listed in the Red Book, and 8 more are expected to be added to them. 6 pear species are now under protection. The territory of the USSR is also characterized by a great diversity of wild cherry. Cerasus blinovskii Totschilina has already appeared in the Red Book, and there are suggestions to include also C. alaica A. Pojark. and C. tadshikistarlica Vass. Steppe cherry (Cerasus fruticosa (Pall.) G.Woron) is placed under protection. Of plum species, Prunus darvasica Temb. is in the Red Book. Three wild plum species are under protection.
The diversity of quince, which is noticeable for great variability of its forms, is gradually decreasing, so the fate of this valuable species is alarming. Therefore it has been suggested that quince should also be included in the Red Book.
Of more than 40 currant species, Ribes ussuriensis Jancz., R. malvifolium A.Pojark and R. armenum A.Pojark are listed in the Red Book, and 14 spp. are protected. 3 spp. of blackberry and 4 spp. of raspberry are guarded in natural reserves. Of the five Actinidia spp. occurring in the Ear East, Actinidia giraldii Diels. is included in the Red Book, but A. poligama (Siebold et Zucc.) Miq. and A. sugawarii need protection as well.
Wild species of grapes are frost resistant and non-susceptible to diseases, thus representing great value for breeding practice. .Wild grape was listed in the Red Book of the USSR. Vitis amurensis and V. sylvestris C.C.Gmel. are protected in natural reserves.
Due to land reclamation the stock of cranberry, whortleberry and blueberry has abruptly diminished. All 9 spp. of this genus (Vaccinium) that can be found in the former USSR, are under protection.
As for other small-fruit plants, the lists of the Red Book are expected to be extended by, adding to them Crataegus pontica C.Koch., Berberis karakalensis and Grossularia burejensis .
One of the most efficient ways to save rare species and genetic diversity is establishment of collections in vivo in botanical gardens and research institutions, and utilization of such species in landscaping and amateur horticulture, so that they ceased to be counted among rare and vanishing forms. Thus, it is complex utilization of wild fruit and small-fruit plants and domestication of most promising plant forms that would significantly provide for attaining the solution of a number of problems faced by breeding practice and applied horticulture.