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CAPRIFOLIACEAE Lonicera caerulea blue honeysuckle Introduction Blue honeysuckle, Lonicera caerulea L. {Caprifoliaceae), is a medium-sized, long-lived shrub with edible blue fruit. The natural distribution of this species, including several different ecogeographic populations, is widespread circumpolar, mostly in the taiga, extending into arctic regions, and more southerly in mountains from middle to alpine zones. It is noteworthy for its extreme cold-hardiness, frost tolerance of flowers, low heat requirements, very early fruit maturity, unique flavours, high content of antioxidant compounds and vitamin C, traditionally recognized medicinal values, ease of care, and few pests and diseases. This species is relatively new as a cultivated crop although vast quantities of these berries have long been harvested from wild plants by indigenous people where edible forms are native; mainly eastern Russia, northern China and northern Japan. Research to develop this berry into a commercial crop began, in the former Soviet Union in the 1950s with selections primarily from L. caerulea ssp. Kamtschatica, edulis, altaica and Lonicera boczkarnikovae. In the 1970s, a research programme was initiated in Hokkaido, Japan, to develop selections from the local subspecies, emphyllocalyx. Very recently, there is interest in north-east China to develop their local taxa, L. caerulea ssp. edulis and boczkarnikovae. Blue honeysuckle is relatively unknown in the Western world, However, as information and plant materials have become available from Russia in the past few years, there is beginning to be some interest to evaluate this new berry crop in Europe, Canada and the USA. World production With the release of cultivars in Russia, since the 1950s, blue honeysuckle has gained wide popularity there as a garden plant and many commercial plantings (10-25 ha) have been established, primarily in western Siberia, Vast quantities of these berries are harvested from both wild and cultivated plants in Russia, but no estimate of the amount is available. In Hokkaido, Japan, many berries are also collected from wild plants, Several selections and one cultivar, 'Yufutsu', released from the Agriculture Experiment Station, have been cultivated only since the mid-1970s and there are about 195 ha under cultivation in this region. Uses and nutritional composition Berries are consumed fresh and are used for a multitude of processed products. They may be eaten as frozen or canned fruit and processed as jam, jelly, juice, wine, soda pop, assorted candies, baked goods such as tarts, fruit cake, etc., noodles, gelatin, ice cream, yoghurt, tea and even chewing gum, Berries are very suitable for juice production because when pressed, using heat and enzymes, they not only yield over 90% juice, but also the colour remains stable in storage. In addition to fruit juice, it is useful as a food additive for enhancing colour in other foods products. The health and medicinal benefits of blue honeysuckle have long been recognized in folklore of indigenous Siberians. In Hokkaido, the Ainu people considered these wild fruit as 'the elixir of life'. Several studies on the chemical composition of fruit that demonstrated exceptionally high vitamin C content and high values for both total phenolics and anthocyanins, all compounds known to contribute to good health in humans. Among 404 samples of four subspecies, vitamin C values ranged from 30.5-103.5 mg/100 g of fresh fruit, and in ssp. emphyllocalyx, berries contained 44.3 mg/100g. There is much variability in both total amounts and types of phenolics among 118 specimens, The highest values were reported for proanthocyanidins (195-625 mg/100g) and free catechins (112-625 mg/100g) with total biologically active polyphenols of 1200-1800 mg/100 g of tissue. Among 11 samples of different subspecies anthocyanin values range from 116-339 mg/100 g fresh weight and total phenolics range from 427-1142 mg/100 g. There is a high correlation between both anthocyanin content and total phenolics with antioxidant capacity. Botany TAXONOMY AND NOMENCLATURE The genus Lonicera contains about 200 species that are widely distributed in temperate and subarctic regions of the northern hemisphere. Many of these are prized as ornamental vines and shrubs for their attractive, and often aromatic, flowers, whereas, only a few have value for their edible fruit. This large, diverse genus has been subdivided into subgenera, sections, subsections, species and subspecies, The blue-fruited species that include the edible form are in the subgenus Chamaecerasus, section Isika and subsection Caeraleae. In the first world taxonomic treatment of Lonicera caerulpolymorphic 4x complex, L. caerulea, with eight subspecies. Regardless of the taxonomic ambiguities, there are definitely ecogeographic populations each of which has characteristic features that have horticultural significance. The common name of this berry In English is blue honeysuckle or blue-berried honeysuckle; in Russian it is zhimolost; and in Japan it is known by the Ainu word, haskap or hasukappu. DESCRIPTION Plants are deciduous, medium-sized shrubs, 1-2.5 m tall and equally broad. Leaves are opposite, simple, oval, ovate, obovate, to lanceolate, 1-5 cm long and 1.3-2.5 cm wide, and may be

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glabrous or have varying amounts of pubescence. Typically, at each node three buds are formed in a vertical series. The lower, and sometimes also the middle, bud develops into a leafy shoot or shoot bearing both leaves and flowers. The upper bud is vegetative only: it remains dormant for 2-5 years and subsequently may form a strong shoot from older wood. Flowers are borne in two-flowered cymes, on 2-8 mm peduncles, in axils of one or both of the opposite leaves at the lower one to four nodes. Corollas are light yellowish to greenish white, tubular, 10-20 mm long, very weakly two lipped, often appearing regular, lobes are much shorter than tube. The vestigial calyx is adnate to the ovary and, in some plants, traces of it appear as projecting double rings of tissue at the apex of mature fruit. Each pair of flowers is situated very close together and it appears that the two corollas are subtended by a single ovary. However, bractlets subtending each ovary are modified to form a surrounding fleshy envelope so that as the ovaries expand, the fused bractlet tissues become the outer layer of a single fruit. A second pair of bracts are located on the peduncle and remain as leaf-like structures until fruit mature. Berries are dark blue, with varying amounts of whitish waxy bloom, and have a smooth or bumpy surface. Shapes may be almost round, oval, ovate, obovate, pyriform, sickle-shaped, jug-shaped, cylindrical, irregular to fusiform. Weight of individual berries varies from 0.2-2.0 g. Some long, narrow fruit may reach 4 cm in length. Flavours vary from very bitter, slightly bitter, neutral, very sour, slightly sour, to tart-sweet, and some have a pleasant aroma. Each fruit has the potential of 20 seeds but the actual number depends upon the adequacy of pollination, Seeds are small, tan to brown, 1-2 mm wide, lens-shaped and soft, so are not objectionable when fruit are eaten. REPRODUCTIVE BIOLOGY Flowering time depends on both spring temperatures and length of the genetically controlled rest period. Under moderate climatic conditions in western Oregon, USA, flowering periods of available subspecies range from the first week of February until the last week of April. In colder regions with a more abrupt rise in spring temperatures, the overall duration is much condensed. Subspecies in order of flowering season, from the earliest to latest, are: edulis and boczkarnikovae (both from the Maritime Province in the Far East); kamtschatica from northern regions of the Far East; kamtschatica from the Kurile Islands and emphyllacalyx from Hokkaido, Japan. The duration of flowering on a given plant may be 1-2 weeks, or longer with prolonged cool temperature,

Flower are hermaphrodite and mostly self-incompatible so that, to obtain good crops, two or more cultivars must be planted together for cross-pollination. All Russian cultivars studied so far are self-incompatible. Although partial self-compatibility is reported in the Japanese cultivar 'Yufutsu', cross-pollination is recommended for optimum fruit set. With adequate pollination, fruit set is generally high and plants bear good srops annually. Successful pollinators include bumblebees, blue orchard bees (Osmia sp.), honeybees and other bees. FRUIT GROWTH AND DEVELOPMENT Fruit development occurs very rapidly, with fruit ripening very early, about 6-S weeks after flowering. Blue honeysuckle berries provide the first fruit crop of the season. The strength of fruit attachment varies from so weak that berries fall readily at maturity to so tight that fruit are ruptured when pulled from stems. Horticulture PROPAGATION Blue honeysuckle is propagated easily by seed or softwood cuttings, with somewhat difficulty by hardwood cuttings, by micropropagation or by division of crowns of older plants. Germination of freshly harvested seeds occurs 3-6 weeks after seeding and is generally good (50-90%), Stratification is not required. Seed viability remains good for about 1 year after harvest, but declines rapidly in succeeding years. TRAINING AND PRUNING As fruit are borne on 1-year shoots, optimum production depends on stimulation of vigorous growth with many flowers. Minimal training or pruning is done on young plants, Thinning of older stems is begun at 3-5 years and every few years thereafter to stimulate growth and to provide optimum illumination for flower and fruit development. When shrubs reach 15-20 years, main branches are headed back to 30-40 cm from the base of the shrea L., all ecogeographic races were included in one polymorphic species, divided, tentatively, into eight, subspecies, and eight forms in Eurasia and North America (Rehder, 1903). Subsequently, other researches have assigned some, or all, of the described taxa to the species level. For example, in The Flora of the USSR Pojarkova (1999) described ten species. In the most recent, comprehensive analysis of the Russian caerulea complex, Plekhanova (1994a) concluded that the 11 socalled species could be reduced to three basic 2x species and on ub which stimulates a vigorous new framework for a rejuvenated plant, With appropriate care, blue honeysuckle shrubs are very long lived and continue to produce good crops for several decades. FERTILIZERS AND NITROGEN Nitrogen is applied in early spring to stimulate vigorous growth, promote flower initia ti on and fruit development, all of which take place between March and early July. Other nutrients are applied as needed according lo soil composition and plant responses. Leaf analyses can be made, but results must be compared to standards established for other crops because optimum values have not yet been developed for blue honey suckle, Soils with high organic matter are suggested, but plants appear to be adaptable to mineral soils as well. They are equally tolerant to soils of pH 5-7. Adequate soil

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moisture is necessary for optimum performance. Application of 10-15 cm of organic mulch is recommended for moisture retention and control of weeds. DISEASES AND PESTS Russian literature claims that no significant diseases have been observed on cultivated blue honeysuckle plants. However a few fungal diseases have been reported on wild plants in the Far East: powdery mildew (Microsphaera lonicerae), leaf spot (Ramularia lonicerae) and Marssonina lonicerae. In Japan, Botrytis has been reported and in Oregon this organism has caused minor damage, manifested as death of a few young shoots in spring. In trials of Japanese blue honeysuckle at different locations in Midwestern USA (where summers are hot and humid), leaf spot or honeysuckle blight (Insolibasidium deformans) was so damaging as to preclude release of certain selections, Several pests attack leaves and fruit of blue honeysuckle, which may reduce both fruit quality and yields. In Russia, the following leaf rollers have been observed: red leaf roller (Archips rosana L.) and currant leaf roller (Pandemis ribeana Hb.). The larvae feed on new growth, destroying the apical growing point and young leaves as they roll the leaves together with a web. Honeysuckle plume moth (Platiptilia caladactyla) larvae feed on the soft flesh and seeds of mature fruit. Damaged fruit turn blue prematurely, become wrinkled and fall from the plant. Honeysuckle aphid (Semiaphis lonicerae Shap.) is a widespread problem in Eurasia; they suck juices of young shoots and leaves, which weakens plants and/or leads to distortion and death of tissues. Occasionally willow scale (Chionaspis salicis L.) and brown scale {Pathenolecanium corni Bouche) are observed. In Japan, the larvae of the yellowish elongate chafer (Heptophylla picea Motschulsky) attack the roots of blue honeysuckle. Bulb larvae and adult inhabit the soil and it is difficult to determine their existence, To confirm their presence a sex pheromone has been identified and is used in traps to attract the male beetles, Birds can be serious pests of blue honeysuckle. In Russia, appreciable damage is caused in winter by bullfinches feeding on buds of shoots exposed above the snow, and in early summer thrushes feed on ripening fruit. In Oregon, birds (especially robins, cedar waxwings and house finches) not only consume abundant fruit, but when perching on plants they also break young shoots wherein lie the initial stages of next year's flowers. HANDLING AND POSTHARVEST STORAGE For fresh consumption, berries are harvested when they reach a dark blue colour, fruit is slightly soft, sugar content is maximum and acid minimal. For processing, they are harvested at a slightly less mature stage when fruit are firmer and acidity levels higher. Commonly, harvest must be done over a period of several days, with two or more pickings for each shrub, because, in most cultivars, all fruit do not mature at the same time. Certain Russian cultivars, for example 'Dossertnaya', 1 'Roxanna', 'Morena', 'Fialka', 'Kamchadalka' and 'Amfora' retain the earliest-ripening berries until a majority of the others have matured, thereby permitting a more concentrated harvest, Compared to other fruit crops, harvest season is very early, It varies with the cultivar and with ambient weather conditions, from early May to mid-June in Oregon, throughout June in Russia and during July in Hokkaido, Japan, Most blue honeysuckle berries are hand harvested. Various aids to harvesting that have been used include shaking shrubs by hand or using a hand-held vibrating machine to shake berries off onto a tarpaulin placed below the shrub. In Japan, a sucking machine to detach fruit has been devised, but it is recognized that much improvement in harvesting methods is needed for efficient harvesting. In Russia some of the newer cultivars that retain berries on shrubs until most fruit are mature can be harvested by most types of berry harvesting machines, Trials with over-the-row berry harvesters, such as those used in the USA, have not been mentioned in the literature, Important requisites for effective machine harvest is the selection of cultivars whose berries have firm skin and flesh, concentrated fruit maturity and moderate strength of berry attachment, In general, blue honeysuckle fruit are relatively soft and have a short post-harvest storage life, However, variation in the texture of skin and flesh among cultivars influences their storability: those with lender skins and soft flesh must be consumed or processed within 1-2 days, whereas those with firmer skins and flesh may be held in a refrigerator for up to 1 week. Most berries are eaten fresh immediately, processed within a few days, or placed in a freezer for later utilization in processed products. MAIN CULTIVARS AND BREEDING Beginning in the 1950s the former Soviet Union began a serious programme to develop blue honeysuckle as a commercial fruit crop. The Vavilov Institute of Plant Industry (VIR) carried out several expeditions to all parts of the country and collected representatives from numerous populations in different ecogeographic regions. Plant materials were distributed to several institutes where evaluations were conducted to determine comparative adaptation of the various subspecies to the different ecological locations and to assess their potential values for cultivar development, There are numerous Russian publications describing these evaluation results as well as studies on taxonomy, botanical characteristics (morphological and anatomical), chromosome numbers, incompatibility, cold hardiness and chemical content of berries. The most valuable subspecies are found in the Far Last; kamtchatica from the northern Magadan and Kamchatka regions and edulis, boczkarnikovae and turcmanizomii from the Southern regions, Primorye and Khabarovsk. Although used less often, two other subspecies offer certain valuable traits. Altaica is widely distributed in European parts of Russia from the Arctic to the Urals, in western Siberia, in eastern Siberia along the Yenisey River and into Mongolia, It is noted for especially high vitamin C and polyphenol content, winter hardiness, drought resistance, firm fruit

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and some forms with good taste. Pallassi, native to north-west Russia, the Urals and western Siberia, has high vigour, resistance to fluctuating temperatures in winter, firm berry skin and flesh, and fruit not falling at maturity, but most fruit have a bitter taste. Not surprisingly, different subspecies are more successful in the different regions. For example, while cultivars derived from edulis and boczkarnikovae arc well adapted to the south-eastern Primorye region, they suffer severe winter damage from fluctuating winter temperatures, in the north-western region of St Petersburg, On the other hand, cultivars derived from kamtschatica are well adapted to the north-west, but they suffer freeze damage from cold, dry winds in Primorye. Because of extreme cold hardiness (to at least - 46°C), short developmental cycle and low temperatures required to stimulate growth, some cultivars can be grown successfully at the VIR-Poolarna Station in Apatity, Russia. This site is located above the Arctic Circle, at nearly 68°N latitude, where there are about 90-105 frost-free days and winter temperatures are severe. On the other hand, none of the Russian blue honeysuckle cultivars can be cultivated successfully in southern regions of Russia, or other regions with moderate climate, due to their very short rest period. As these plants complete their rest very early (SeptemberOctober), they often exhibit autumn flowering. They become de-acclimated so that subsequent relatively mild winter temperatures of a few degrees below 0°C result in freeze damage to buds, Also, flowers open very early and, although not damaged by frosts at this stage (flowers can tolerate -8 to 10°C), poor fruit set and a high proportion of small, seedless fruit result due to insufficient pollinator activity in the cool temperatures of early spring. Among the Russian blue honeysuckle germplasm there is a form of kamtschatica on the Kurile Islands that has a considerably longer rest period. These forms are not represented among the Russian cultivars but appear well adapted to the moderate climate in Oregon and hold promise for breeding in this region. Over the past five decades in Russia, many cultivars have been selected and named, primarily from eight major government research centres distributed across the country: Pavlovsky (near St. Petersburg), Moscow, Chelyabinsk, Novosibirsk, Nishniy Novgorod, Bakchar, Barnaul and Vladivostok. Minor selection programmes are carried out in several other locations. Also, it is common practice for individuals to grow seedlings in their own gardens and select the best ones for local propagation. Consequently, a multitude of genetic types are grown in Russia (Plekhanova, 2000). Most of these cultivars are selected from openpollinated seedlings (first or second generation) of forms selected from wild populations. Only 'Viola' and 'Morena' are mentioned as being from specific controlled 1 crosses, a few are a result of pollination of a selected form with mixed pollen, and 'Sibiryatchka is a cross between ssp. kamtschatica and turczaninowii. There is still considerable variation with which to make significant selection advances and, annually, new cultivars are being released. All of the subspecies used in cultivar development are tetraploid (2n = 36) and crosses among them been fully compatible. (The diploid status of l. boczkarnikovae prevents its use in breeding with the other subspecies.) In the past several years, blue honeysuckle selection programmes, using Russian plant materials, have been initiated in Romania, Czech Republic, Latvia, Sweden, and Oregon (USA). In the 1970s, selection work began in Hokkaido, Japan, using the locally available subspecies, emphyllocalyx. In addition to “Yufutsu”, several selections have been distributed to farmers who have developed a small industry of fresh and processed products. This subspecies is notable for having the longest dormancy; in Oregon, plants bloom 2-4 weeks later than Russian forms and are, therefore, much more adapted to moderate climate regions. Recently, in north-eastern China where wild berries (ssp. edulis and boczkarnikovae) have long been harvested, there is increasing interest in selecting elite forms for commercial production to augment the supply for the already-established processing plants. Major characteristics sought in new cultivars are high production, large fruit, self-fertility, traits to facilitate mechanical harvesting such as upright plants with flexible shoots and retention of ripe fruit on plants or simultaneous fruit maturity. Fruit skin and flesh must be firm for the fresh market and for mechanical harvesting, berries should have moderately firm attachment. Other characteristics include a superior flavour and a high content of nutritional components, especially Vitamin C and the antioxidant compounds (polyphenols). To extend cultivation into regions of moderate climate, cultivars must remain dormant through fluctuating temperatures in autumn and winter. For severe climates where plants remain dormant due to continual low winter temperatures followed by abrupt spring warmth, early fruit maturity is desired. Maxine M. Thompson, Department of Horticulture, Oregon State University, Corvallis, Oregon, USA

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Source: The Encyclopedia of Fruit & Nuts. By Jules Janick, Robert E. Paull. CAB Inernational, Oxfordshire, UK. 2008. ISBN 0-85199-638-8. pp. 232-236

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