Red Bayberry: Botany and Horticulture* - download.xuebalib.com

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Red Bayberry: Botany and Horticulture*Kunsong Chen, Changjie Xu, and Bo ZhangDepartment of HorticultureHuajiachi Campus, Zhejiang UniversityHangzhou, 310029, P. R. China

Ian B. FergusonThe Horticulture and Food Research Institute of New ZealandPrivate Bag 92 169Auckland, New Zealand

I. INTRODUCTIONA. HistoryB. DistributionC. Commercial Production

II. BOTANYA. TaxonomyB. Morphology and Anatomy

III. PHYSIOLOGYA. Vegetative GrowthB. Flowering and Fruit SetC. Fruit Development

IV. ENVIRONMENTAL REQUIREMENTSA. TemperatureB. WaterC. SoilD. LightE. Elevation and Exposure

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*This review was supported by the State Key Basic Research and Development Plan(G2000046806), the National Natural Science Foundation of China (30170660), and Zhe-jiang Natural Science Foundation (ZD0004), and was also a part of a cooperative programbetween The Horticulture & Food Research Institute of New Zealand and Zhejiang Uni-versity. We thank Dr. Grant Thorp for critically reading the manuscript.

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Horticultural Reviews, Volume 30 Edited by Jules Janick© 2004 John Wiley & Sons. ISBN: 978-0-471-35420-8

V. HORTICULTUREA. PropagationB. Field CultivationC. Pests and DiseasesD. Harvest and HandlingE. Storage and TransportationF. Processing

VI. CONCLUDING REMARKSLITERATURE CITED

1. INTRODUCTION

Red bayberry (Myrica rubra Sieb. & Zucc., Myricaceae) is a subtropicalfruit tree native to China and other Asian countries, bearing a delicious,berry-like fruit (Fig. 3.1). Gengmin Wu, founder of modern Chinese hor-ticulture, praised it as a “precious Southern Yangtze fruit of early sum-mer ” (Wu 1995). The fruit ripens in June and early July in the mainChinese production areas of Zhejiang and Jiangsu provinces, earlierthan most other local fruits. The rich red colors and appealing flavormake this juicy fruit popular with consumers; it is eaten like a cherry.

84 K. CHEN, C. XU, B. ZHANG, AND I. FERGUSON

Fig. 3.1. Red bayberry (Myrica rubra) fruit and trees. A and B: mature fruit showing (B)the segmented juicy flesh and the hard stone. C: fruit growing on the outer space of thecanopy. D: trees growing on hillsides, a common cultivation practice in China. Photos byJiangguo Xu.

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In addition to being consumed fresh, various products such as juice,canned fruit, jam, wine, sweets and salted fruit are produced. Present-day commercial cultivation is still largely restricted to China.

The fruit and roots of red bayberry have been used as important com-ponents of traditional Chinese medicines for more than 2000 years (Li1578), the fruit being beneficial for treating congestion, coughs, diges-tive problems, and diarrhoea. The root also has wound healing proper-ties. In recent years, a number of pharmaceutically active compoundshave been identified from the various plant parts (Zhang et al. 1993; Chiet al. 2000; Yi and Liu 2000; Zhong et al. 2000).

The evergreen tree has a bushy, round canopy and grows well in soilsof low fertility, having an association with the nitrogen-fixing bacteriumActinomyces frankia. The tree is used in China to increase the organicmatter content of soil, reduce soil erosion, and to enhance the landscape(Wang and Chen 1989). Red bayberry is often interplanted with existingvegetation such as pine or other natural forest trees (Wang et al. 2001).

While the fruit is well known throughout China, where there is a con-siderable body of literature on various aspects of production, it is littleknown elsewhere. There is a short general review on red bayberry avail-able in English (Li et al. 1992), and a review of research progress in Chinahas recently been published (Li et al. 1999). This review will cover the botany and horticulture of red bayberry, most of it based on Chinesepublications.

A. History

In China, red bayberry has been known by a variety of names. Yangmeiis the most common name in Chinese. Shizheng Li, in Compendium ofMateria Medica (1578), wrote: “The shape of the tree is similar to poplar(Yang), and the taste of the fruit is somewhat like mume (Mei), thus itis named Yangmei.” Shumei (strawberry tree) is used in Taiwan.Zhuhong is a common name in Fujian province and, elsewhere in China,names such as Shanyangmei and Zhurong are used. The English namesfor this fruit include red bayberry, Chinese bayberry, and waxberry.

The fruit has a very long history in Chinese civilization. The earliestrecords come from the Neolithic site at Hemudu, Zhejiang province, indi-cating that the fruit has existed as a foodstuff for more than 7,000 years(Yu 1979; Wu 1984). Red bayberry fruit and stones have also been foundin the Mawangdui tumulus of the Western Han Dynasty (206 B.C.E.–25 C.E.)in Hunan province and the Luobowan tumulus in Guangxi ZhuangAutonomous Region (Yu 1979). Nan Fang Cao Mu Zhuang, a book on theproperties of various plants from southern China, written by Ji Han dur-ing the Jing Dynasty (265–420), recorded the cultivation of red bayberry

3. RED BAYBERRY: BOTANY AND HORTICULTURE 85

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and its use in wine making (Ji 304). By the Song Dynasty (960–1279), theWu-Yue area (Jiangsu and Zhejiang provinces today) was well known forred bayberry production and the fruit recognized for its quality and quan-tity; locations close to Ningbo and Taizhou in Zhejiang province are stillthe most important production areas.

B. Distribution

Red bayberry originated in southeastern China, where it is still found inthe wild and is the source of seed for rootstocks. It is now distributedsouth of the Yangtze River and north of Hainan Island, approximately97° to 122°E longitude, and 20° to 31° N latitude. This distribution issimilar to that of citrus, loquat, tea, and bamboo, except that red bayberrycan withstand lower temperatures (Maio and Wang 1987; Maio et al.1995). The major commercial production area is concentrated in Zhe-jiang, Fujian, Jiangxi, Jiangsu, Guangdong, and Guizhou provinces.There is some production in Yunnan, Guangxi, Sichuan, Hunan, Shanxi,and Taiwan, from semi- or wholly wild trees (Wang 1995).

Outside of China (Yu 1979; Wang 1987) the crop is grown in Thailand,although fruit quality is often poor and the area limited. In Japan, it isgrown in Tokushima, Kochi, Ehime and the western part of Honshu. InEurope and America, red bayberry trees are used mainly for ornamen-tal purposes. There are a number of closely related species (describedbelow) that are cultivated. Myrica integrifolia Roxb. is distributed inIndia, Sri Lanka, Burma, and Vietnam, where it is confined to home gar-dens, producing small and acid fruit, usually used for jam or medicine.Myrica esculenta Buch.-Ham. is found in India, Nepal, and Vietnam aswell as in southwest China. Myrica faya Ait. has fruit suitable for freshconsumption and is grown in the Canary Islands.

C. Commercial Production

Production of red bayberry has increased dramatically; the cultivatedarea in China in 1995 was 130,000 ha. The crop has become one of themost important fruit tree crops in south China (Liu 2000; Wang et al.2001). In Zhejiang province, the cultivated area and production were4,400 ha and 26,500 tonnes (t) in 1959, 17,500 ha and 46,200 t in 1985,and 38,378 ha and 129,750 t in 2000 (Wang et al. 2001). As a result, redbayberry is second only to citrus among the fruit crops of the province,and the yield is expected to continue to increase. Most production isconsumed locally, but an increasing proportion is being exported bothwithin and outside of China.


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II. BOTANY

A. Taxonomy

1. Species. The Myricaceae are widespread in tropical, subtropical, andtemperate areas of the world. They consist of two genera, Comptonia andMyrica, both of which are cultivated. The genus Myrica Linn containsmore than 50 species of which six are found in China (Yu 1979; Maioand Wang 1987; Qu and Sun 1990; Wang 1995; Li et al. 1999). Morerecently, RAPD (Random Amplified Polymorphic DNA) markers havebeen successfully used in classification and identification of Myricaspecies (Lin et al. 1999). Myrica cerifera L. originating from North Amer-ica was clearly distinguished from three Chinese species (Myricaadenophora Hance, Myrica esculenta Buch. -Ham, and Myrica rubraSieb. & Zucc.), which clustered together.

Myrica rubra Sieb. & Zucc. Red bayberry (2n = 16) is an evergreen treegrowing to a height of 5 to 10 m, distributed in southern China, but alsofound in Japan, South Korea, and The Philippines. The bark of youngtrees is smooth and yellow-green, while that of old trees is grey-brownwith white spots and narrow cracks. The canopy is uniform and roundor slightly flattened. The branches are frail and easily broken, and theleaves alternate and simple, with blades 5–14 cm long and 1–4 cm wide,usually with smooth margins, although sometimes serrated. The upperand lower leaf surfaces are smooth without hairs, the upper lustrous anddark green and the lower light green. The plant is dioecious, althoughoccasionally monoecious, with the inflorescence forming in axillarybuds. The staminate inflorescence is a compound catkin, 1–3 cm long,columnar, and yellow-red; the pistillate inflorescence is a simple catkinand shorter and thinner, filaceous, bright red, with two longitudinalgrooves along the stigma. The fruit is a small drupe and consists of afleshy pericarp comprising individual segments and a hard endocarpprotecting a single seed. It is red, purple, white, or pink when ripe,depending on the cultivar. Flowers bloom during February to April andfruit ripen during May to July.

Myrica esculenta Buch.-Ham. This is also known as Yangmei Dou inGuizhou. It is mainly distributed in mountains at elevations of1,500–2,500 m in southwest China (Sichun, Yunnan, Guizhou, Guang-dong, and Guangxi), and in India, Nepal, and Vietnam. The tree is 4–15m high, with light-colored bark. The shoots are thin and covered withnumerous hairs. The leaves are thick, hairless, and oval, 3–12 cm long


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and 1.2–4.5 cm wide, with few or no marginal indentations and sparseyellow glands on the lower surface. The petiole is covered with whitehairs. The plant is dioecious and the inflorescences are catkins, the flow-ers having two bright red, thin stigmas. The fruit are ovoid, about 1 cmlong and 0.8 cm in diameter, with an average weight of about 0.5 g, andwith red flesh. The edible portion constitutes about 80% of the fruitweight and, when ripe, the soluble solids concentrations are about 12.5%and total acids 1.3%. Flowers bloom during September to October andfruit ripen during the following March to April. There are seven sub-species or variants of this species, which can endure high humidity andtemperatures down to –6°C, and which will also grow well in dry areas.

Myrica nana Cheval. This species is variously known as Yunnan Yang-mei and Dian Yangmei and is mainly distributed in subtropical and tem-perate zones of Yunnan, Guizhou, and Xizhang in China. The plant is ashrub 0.5–1.0 m high, with thick, strong shoots. The bark is rich in tan-nin, and the olive green leaves are narrowly obovate or occasionallyelliptic. The upper leaf surface usually has small depressions associatedwith yellow glands and sunken venation; the lower leaf surface hasglands and protruberant venation. Petioles are short and covered withshort soft hairs. Fruit are round to oblate, about 2 cm long and 2 cm indiameter, with an average weight of 3.5–5 g. Ripe fruit are red, with an80% edible proportion and soluble solids levels of 9–10% and totalacids of nearly 4%. Flowering may last 1 month from February to March,and fruit normally ripen about 4–6 months after flowering. The specieshas four variants and two derivatives: M. nana var. integra Cheval., M.nana var. luxurians Cheval., M. nana Cheval, var. humifusa N. Liu et Z.F. Li, var. sp. nov., M. nana Cheval, var. alba N. Liu et Z. F. Liu et Z. F.Li var. sp. nov., M. nana cheval, f. cerea N. Liu et Z. F. Li, f. niv. and M.nana Cheval, f. gracilifolia N. Liu et Z. F. Li, f. onv.

Myrica integrifolia Roxb. This species is mainly distributed in the moun-tains of South Asia at an elevation of 900–1,400 m in countries such asIndia, Sri Lanka, Burma, and Vietnam, and also in the western part ofYunnan in China. It is a large evergreen shrub or tree, 8–10 m high withdense shoots covered with dense soft hair. Leaves are lanceolate, brightgreen, with smooth margins, but sometimes undulate. The plant is dioe-cious, with oval, red, acid fruit when ripe, weighing about 2.4–3 g, with10.5% soluble solids and an edible portion of about 85%. Flowers bloomduring February to March, and fruit ripen from April to May. The speciesprefers an acid soil and high humidity, and usually grows in foreststogether with deciduous plants.


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Myrica arborescens. S. R. Liet X. L. Hu, sp. nor. The species is distrib-uted in the south and southwest part of Yunnan in China, and in Burma,growing in the mountains at an elevation of 900–1,400 m. Plants preferan acid soil and humid climate. It is an evergreen tree, about 15 m inheight, with a trunk of more than 300 cm in circumference. Shoots havelong white hairs and few glands, and the leaves are larger than for otherspecies, with blades 8–19 cm long and 2–4 cm wide, elongated lanceo-late or ellipsoidal in shape, and having obvious sharp sawtooth edgeson the abaxial sides. The upper venation of young leaves is covered withwhite soft hair, while yellow glands cover the lower surface, and the sec-ondary veins are also covered with long white soft hair. Plants are dioe-cious, with an ovary surrounded by long hairs and the fruit are roundor ovoid, 2.5–3 cm in diameter and yellow-white or green-white whenripe. Flowers bloom during February to March, and the fruit ripen fromApril to May.

Myrica adenophora Hance. Known variously as Xiyeyangmei, Pomei,and Qingmei, it is mainly distributed in Hainan province, the southernpart of Guangdong province and southwestern Guangxi province. Thevariant M. adenophora var. kusanoi Hayata is grown in Taiwan. It is ashrub or small tree, 1–6 m high. The bark is gray and the young thinshoots are covered with short soft hair and yellow glands. Leaves areobovate, both sides with numerous glands. The medial vein has shortsoft hair, as does the petiole. Staminate and pistillate inflorescences formin axillary buds. The red fruit are oval, small, and less than 1 cm in diam-eter. Flowers bloom from October to November, and the fruit ripen dur-ing February to May.

2. Cultivars. There is little agreement on cultivar classification. Fruitcolor and ripening date have been used to identify different groups ofcultivars (Yu 1979; Wu 1984; Maio and Wang 1987; Qu and Sun 1990).Guo and Li (1994) sorted the cultivars into five groups and nine typesbased on physical characters of the stone, fruit, and leaves, while Chen(2000) divided them into two types based on soft and hard fruit flesh.The Chinese Red Bayberry Cooperation Association has establishedthree types based on the fruit ripening date (Chen 2000). Recently, per-oxidase isozyme analysis, chromosome banding, and karyotypic analy-sis have been introduced into varietal classification (Lin et al. 1999).

Ripe fruit color is one of the more useful criteria used (Qu and Sun1990; Li et al. 1992), and this has resulted in four cultivar groupsdescribed as follows:


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Wild. This group, also called wild black, is found growing in thewild and is used as rootstocks. The fruit are red and acid, withsmall flesh segments, and ripen earlier than other types, in Zhe-jiang at about the beginning of June.

Red. Fruit of this group are red when ripe, and usually larger and ofbetter quality than other types. Representative cultivars include‘Shuimei ’, ‘Chise’ , ‘Dongkui’ in Zhejiang, and ‘Dayexidi ’ inJiangsu.

Black. This group has the best fruit quality, with large fleshsegments and a stone that can be easily separated from the flesh.The fruit turns from red to red-black during ripening. Representa-tive cultivars include ‘Biqi’ in the Cixi-Yuyao district, ‘WandaoYangmei’ in Dinghai, ‘Ding-ao Mei’ in Wenzhou, ‘Datanmei’ inYuhang in Zhejiang, ‘Wumei’ in the Dongting area in Jiangsu, and‘Shanwu’ and ‘Wuhesu’ in the Chaoyang area in Guangdong.

White. The ripe fruit of this group are various shades of white. Yieldand fruit quality is less than for fruit of the black or red groups,and it is not so widely planted. ‘Shuijing Yangmei’ (crystal-looking) in Shangyu is the best cultivar of this type grown in Zhe-jiang province.

Zhang and Miao (1999) distinguished 268 cultivars in China. Fruitcharacteristics vary widely among these cultivars, as shown by the percentage of cultivars in different groups on the basis of ripening date,fruit color, and fruit weight (Table 3.1). The cultivars in Zhejiangprovince can be sorted by ripening date into three groups (Table 3.2).


Table 3.1. Distribution of fruit attributes among different Chinese cultivars of redbayberry. Source: Zhang and Miao (1999).

Ripening Date Flesh Fruit Size

Distribution Distribution Weight DistributionMonth (%) Color (%) (g) (%)

April 1.1 White 9.3 <6 6.3May 6.3 Pink 5.6 6.1–9 25.8Early June 13.7 Red 17.2 9.1–13 46.6Mid June 18.7 Deep red 7.8 13.1–15 14.9Late June 47.8 Purple 37.3 >15 6.3Early July 12.4 Deep purple 3.4

Purple black 13.8Jet black 5.6

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4080 P-03 9/17/03 11:04 AM 1

B. Morphology and Anatomy

1. Roots and Nitrogen Fixation. The trees have a shallow, fibrous rootsystem, usually occupying the top 5 to 40 cm of the soil, and typicallyone- to twofold greater than the diameter of the canopy. The plants forman association with Actinomyces frankia, a nitrogen-fixing bacterium.The nodules are usually greyish yellow, fleshy, and randomly distrib-uted on the roots (Miao and Wang 1987; Wang 1995). In transverse sec-tion, the nodules are round and symmetric, and their color changesfrom oyster white to yellow brown with maturation, and dark brownwith senescence (Wang and Huang 1990). Nitrogenase activity of maturenodules is higher than that of the young ones, with two peaks of activ-ity observed in June and October. The lowest activity is found in Janu-ary, and can be inhibited by nitrate (Wang and Huang 1990; Wu and Gu1994). Measurements by Z. Li et al. (1993) have shown that the averagenodulation mass in a 7-year-old red bayberry sapling was 52 g/tree with460 kg/ha of nitrogen fixed per year. There are clear advantages in thisnitrogen-fixing capacity in terms of fertilizer use and soil fertility.

2. Shoots. The bark color varies with development stages, from pale yellow-green in young trees to grey-brown in mature trees. The maturebranches, which have very visible lenticels, are weak and easily brokenby wind. There are four types of shoots: rapidly growing extensionshoots (water shoots), vegetative shoots, bearing shoots, and staminateflowering shoots (Miao and Wang 1987; Wang 1995). Water shoots areusually longer than 30 cm and vegetative shoots shorter than 30 cm, withlonger internodes. Well-developed axillary buds on vegetative shoots arethe potential fruiting shoots.

New leaf and shoot growth generally arises from buds near the shootapex (Miao and Wang 1987). The season of growth affects leaf size: Thespring leaves are the biggest, followed by those produced in the summer,and then the autumn. Leaf color also varies with the season; the springleaves are deep green, in the summer a lighter green, and autumn leavesare pale green. These characters are also used to estimate nutritional sta-tus. Leaves remain on the tree usually for 12–14 months, with a markedpeak in abscission just prior to the spring growth flush.

3. Flowers. Flower buds of red bayberry are simple, forming in axillarybuds and never in terminal buds, where only vegetative (leaf) budsoccur. The flower bud is larger than the leaf bud, and can be distin-guished in winter before budbreak. New growth in spring occurs fromaxillary buds on shoots grown in the previous season. Flower bud dif-ferentiation has been well studied, mainly on ‘Xiyeqing ’and ‘White’ cul-


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tivars (Li and Dai 1980). Only apical buds and 4–5 axillary buds candevelop into leaf or flower primordia; the other buds remain latent forquite some time and can be stimulated to develop into shoots. Thischaracter is useful when replacement of the canopy and fruiting shootsis needed. Leaf buds break about 20 days later than flower buds, and leafunfurling occurs about 15 days after that.

Red bayberry is a typical dioecious fruit tree, but it is difficult to iden-tify sex before flowering. G. Li et al. (1993) established a method basedon isozymes patterns and composition of phenolic compounds. Theflower is small, unisexual, without perianth, and is wind-pollinated.Each staminate flowering shoot can contain 2–60 inflorescences, nor-mally between 15 and 20, and is part of a compound inflorescence thatbears 15–36 catkins, each catkin composed of 4–6 staminate flowers.Staminate inflorescences form in the leaf axil, and are cylindrical or longconical in shape, with the color changing from garnet in young flowersto yellow-red or bright red in mature ones. The distal staminate flowersopen first, and the flowering period can be as long as 40–50 days for awhole tree. Staminate flowers are arranged as a corymb, without pedicelor receptacle, and are surrounded by greenish white bracts. Each stami-nate flower has two stamens, and unequal filament length (Fig. 3.2). Thefilaments are yellowish red or bright red, and usually bear anthers at the apex. Anthers are kidney-shaped, bright red, fused at the base, and


Fig. 3.2. Morphology of staminate floral structure of red bayberry (from Wang 1995).

1. Staminate flowering shoot. 2. Staminate compound catkin. 3. Individual staminatecatkin. 4. Bract for compound catkin. 5. Bract. 6. Stamen.

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Fig. 3.3. Morphology of pistillate floral structure of red bayberry (from Wang 1995).

1. Pistillate flowering shoot. 2. Pistillate inflorescence. 3. Pistillate flower. 4. Bract forinflorescence. 5. Bract. 6. Pistil. 7. Longitudinal section of fruit. 8. Flesh segment.

release yellow pollen through longitudinal splits. The pollen grains aresmall (20 µm diameter) and can be carried as far as 1000 m by wind (Miaoand Wang 1987). Each anther holds more than 7,000 pollen grains, andeach staminate inflorescence contains 200,000–250,000 pollen grains.

Each pistillate flower shoot has 2–60 pistillate inflorescences, theaverage being 15 to 20. The catkins contain 7–26 flowers (average 14).The ovary is unilocular, and the style bright red, 0.5–1 cm in length, witha Y-shaped stigma with 2, sometimes 3–4 sites of dehiscence. Terminalflowers of the pistillate inflorescence usually flower earlier than others(Fig. 3.3), and the flowering period for a whole tree may last for about30 days. Occasionally, mixed inflorescences occur with pistillate flow-ers at the top and staminate flowers at the base (Fig. 3.4). Staminate flow-ers open after 2–3 pistillate flowers have opened in the sameinflorescence. However, pistillate flowers in a staminate inflorescencehave only been reported once (Miao and Wang 1987).

4. Fruit. The fruit have stones like peach and plum, with an edible partmore like a berry (Fig. 3.1). The fruit is usually spherical, and the skinhas a waxy coat (Miao and Wang 1987). Fruit size varies among culti-vars (Table 3.2), generally being greater than 2 cm in diameter, with somereaching 3 cm or more. Fruit of the wild types are less than 2 cm in diam-eter, and fruit of Myrica nana Cheval grown in Guizhou, China, are thesmallest, measuring less than 1 cm in diameter.

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The epicarp of the fruit consists of thin-walled parenchyma cells, inwhich the vascular bundles are arranged like a cup. The parenchyma-tous mesocarp makes up the edible portion. The endocarp consists of ahard stone with small, round, thick-walled sclerenchyma cells, most ofwhich are flattened. The stone includes a seed coat, embryo, and large,soft, waxy cotyledon (Fig. 3.5). The epicarp and mesocarp (flesh seg-ments) develop from the outermost layers of endocarp and usually con-sist of 1,100–1,300 flesh segments.

The length, thickness, pointedness, and hardness of the flesh seg-ments varies with cultivars. Tree age, yield, soil nutrition, humidity,degree of maturation, and position of fruit on the tree influence fruitquality (Li et al. 1992). More mature trees, heavier fruit loads, moreabundant nutrition, drier climates, and sun exposure will result in fruitwith more pointed flesh segments. In some cultivars, a single fruit maycontain both round and pointed segments. The former would be located


Fig. 3.4. Inflorescences of red bayberry (from Liu 2000).

1. Staminate inflorescence. 2. Bisexual inflorescence. 3. Pistillate inflorescence.

Fig. 3.5. Morphology of the fruit of red bayberry (from Miao and Wang 1987).

1. Epicarp. 2. Mesocarp (flesh segment). 3. Endocarp. 4. Seed coat. 5. Seed (cotyledon).

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in the middle of the fruit, with the latter in the outer parts. Fruit withround flesh segments are usually more succulent and taste better, whilethose with sharper flesh segments tend to have a longer storage life.

III. PHYSIOLOGY

A. Vegetative Growth

Root growth usually commences in late February, and the root systemhas three major growth peaks, in late May, mid-July, and early October(Miao and Wang 1987). Vegetative growth has up to three growth flusheseach year. Summer shoots are the most abundant, accounting for60–70% of the total shoots each year, and these make up most of thebearing shoots in the following season; spring shoots, summer shoots,and sometimes autumn shoots will become flowering branches. Wintershoots can develop into bearing shoots depending on weather and nutri-tion (Miao and Wang 1987). Spring shoots occur from late March to lateJune, developing from the spring shoots or summer shoots of the previ-ous year; summer shoots, from June to August, developing from thespring shoots of the same year and bearing shoots of the previous year;autumn shoots, from early August to October, developing mainly fromthe spring and summer shoots of the same year (Li 2001). Except for thecultivars ‘Biqi’ and ‘Ding-ao’, autumn shoots do not become bearingshoots, as they form too late (Miao and Wang 1987). As might beexpected, spring shoots are the longest and autumn shoots the shortest.

Leaves unfurl during late March to early April, and develop rapidlyin May. Old leaves begin to abscise at the beginning of May, and reachan abscission peak when spring shoots stop growing. Leaf abscission isinfluenced by both the growing environment and the cultivar. Treesgrowing on clay soils, attacked by pathogens, or generally weak trees,usually shed leaves earlier, and abscission is postponed in late matur-ing cultivars such as ‘Wandao Yangmei’.

B. Flowering and Fruit Set

Flower-bearing shoots develop from the strong spring and summer shootsof the previous year. Although spring shoots are the best shoots for bear-ing fruit, they are not sufficient for adequate crop loads, and since sum-mer shoots are the most abundant, they become the most important sourceof fruit and the key factor influencing yield in the next year (Li 2001). Thefruit capacity of a bearing shoot varies with shoot length, and shoots aredivided by length in the ‘Biqi’ cultivar into four types: extended, long,


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medium, and short shoots (Miao and Wang 1987). Extended shoots aremore than 30-cm long with limited flower buds at the end and most of thebuds will be shed after flowering. Long shoots are thin, 20–30 cm in length,with 5–6 flower buds at the end, and a low rate of fruit set. Medium shootsare 10–20 cm long, with a heavy load of flower buds except at the apex;these shoots bear the highest fruit load. Short shoots, 1–10 cm in length,some as short as 1–2 cm, carry many flower buds, with high rates of fruitset. When flowering shoots constitute about 40% of the total shoots, ahigh, steady yield can be predicted (Chen et al., pers. comm.), but whenthis ratio is more than 60%, alternate bearing may develop.

Flower bud differentiation begins shortly after the cessation of sum-mer shoot growth (Li and Dai 1980). Physiological differentiation ofinflorescence primordia of the ‘Xiyeqing’ and ‘White’ cultivars occursin early or mid-July. During the early stage of flower bud differentiation,abortive pistillate inflorescences emerge and these will be shed ratherthan open in the next spring. Inflorescences that differentiated afterearly August normally develop fruit. Morphological differentiation of theprimordia of pistillate inflorescences begins in mid-July, and the firstsmall flower primordium forms in late July. The formation of primordiaof the staminate inflorescences begins at the end of the same month.Flower bud differentiation stops at the beginning of December. Physio-logical differentiation of the flower buds develops 2–4 weeks earlier thanmorphological differentiation, and takes about 3 months to complete.Autumn shoots are unable to develop flower primordia in time for thenormal flowering period.

Flowering date varies according to cultivar and growing conditions(Miao and Wang 1987). Some staminate flowers open in late January,some during February and March, reaching full bloom in March to April.This also happens with pistillate flowers and, as a result, individual pis-tillate inflorescences commonly carry fruit and opening flowers at thesame time. Flowering can be divided into six stages: bud break, inflo-rescence break, first bloom, full bloom, end of bloom, flower drop (Miaoand Wang 1987). Usually, the first bloom stage is when 5% of anthers orstigmas are exposed, full bloom stage is at 75%, and end of bloom whenthe anther exposes pollen and becomes yellowish-brown or the stigmawilts (Miao and Wang 1987). The period of flowering can span 39 daysfor staminate flowers and 27 days for pistillate flowers. Though pistillateflowers open later and last for a shorter time than the staminate ones, fullbloom stage is longer (13 days) than that of the staminate flowers (5–7days), and this benefits pollination (Miao and Wang 1987).

The highest fruit set occurs in the uppermost five inflorescences on bear-ing shoots, but the first inflorescence is the predominant one, bearing


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20–45% of the total fruit. The rate of fruit set is only 2–4% for the wholetree (Wang 1995). The main peak in abscission of inflorescences andfruitlets is late April to early May. Additional peaks occur in the middleof May and just prior to harvest in some cultivars such as ‘Shuimei’ and‘Hunanzhong’, but not in the cultivars ‘Dongkui’ and ‘Wandao Yangmei’(Miao and Wang 1987).

C. Fruit Development

The time from fruit set to maturation is 60–70 days (Miao and Wang1987). The fruit of leading cultivars in Guangdong and Fujian ripen dur-ing late May to early June, the early-maturing cultivars in Zhejiang andJiangsu during middle to late June, and the late-maturing cultivars inearly July. Fruit on trees in inland areas ripen earlier than in coastal areasbecause of greater diurnal temperature differences in inland climates.

Fruit growth follows a double sigmoid curve in both fruit size (diam-eter; Fig. 3.6) and fruit weight. For example, ‘Biqi’ and ‘Dongkui’ fruit(Miao and Wang 1987; Gong 1995) develop rapidly and reach the max-


Fig. 3.6. Changes in length, diameter, and ratio of length to diameter during fruit devel-opment of ‘Donkui’ red bayberry (from Gong, 1995).

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imum of the first growth stage (about 20 days) just after the first peak offruit abscission in early May. This period of rapid growth is followed bya pit hardening stage (15–20 days) and a second burst in fruit growth,characterized by increases in water content, weight, and color of fruitjust prior to fruit ripening on the tree. Fruit size increases synchro-nously with fruit weight and there is a strong correlation between thesize of the seed and the fruit.

Water content of the fruit increases from the fruitlet to the pit hard-ening stage, then decreases gradually, before increasing again as thefruit matures (Miao and Wang 1987). The daily increment in fresh weightof the fruit flesh during the maturation stage is three times that at the firstrapid growth stage; there is no similar difference in dry weight increase.The length of the pit hardening stage is influenced by fruit size as wellas cultivar—the bigger the fruit, the shorter the length of the stage. Totalsoluble solids (TSS) contents increase with fruit maturation to the pointof harvest, with sugars accumulating rapidly during the final 2–3 weeks(Chen et al. 1992). Larger fruit are commonly sweeter than smaller ones,and there is a positive correlation between TSS content and degree ofpigmentation.

Citric acid is the most abundant of the fruit organic acids, accountingfor 97% of the total, with malic, oxalic, succinic, isocitrate, fumaric andother acids making up the remaining 3%. Chen et al. (1992) found thattotal acidity increased rapidly from about 40 days before harvest, but thendecreased as the fruit began to ripen on the tree. Smaller fruit tend to havehigher acidity than larger ones (Chen et al. 1992).

The pigments responsible for the fruit flesh color (red, and purple toblack) are anthocyanins, the levels of which vary with cultivar, fruitdevelopment, and environmental factors, especially light. Cyanidin-3-glucoside has been identified as the principal fruit pigment, withpelargonin-3-monoside and delphinidin-3-monoside as minor compo-nents (Lin 1984; Ye et al. 1994). Chlorophyll contents decrease duringfruit maturation.

IV. ENVIRONMENTAL REQUIREMENTS

A. Temperature

The tree performs well in tropical, subtropical, and temperate zones,with optimum temperatures of 15–20°C. It can endure winter freezingwith average temperatures of more than 2°C and an absolute minimum


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above –9°C. However, the trees can be damaged and the yield for the fol-lowing year reduced by more than 20% if the minimum temperaturefalls below –9°C and a maximum temperature of less than 0°C lastslonger than about three consecutive days. Because the flowering periodis quite late, unlike peach and apricot, flower or fruit freezing seldomoccurs. To get high yields and quality, the growing conditions shouldinclude an annual average temperature >14°C and accumulated tem-perature (>10°C) of more than 4,500 degree days. Outside these condi-tions, small, very acid and poor-tasting fruit are likely to be produced.High temperatures during May and June, during the second fast growthphase, also may result in fruit with high acid and low sugar contents.For example, one study has shown that when the mean May–June tem-perature was 20–22°C, the acid content was 0.7–1.3% and the ratio ofsoluble solids to acids was 9–16, but when the mean temperature wasraised by 2°C, the acid content increased to 1.4–1.9% and the ratiodecreased to 6–7 (Miao and Wang 1987). High temperatures (e.g., a meantemperature higher than 28°C) can cause damage, particularly to young,newly transplanted trees, and affect the development of flower buds andfruit-bearing shoots. The optimum temperature for photosynthesis of redbayberry is less than 20°C (Ruan and Wu 1991).

B. Water

High humidity and a plentiful water supply assures high cropping andhigh-quality fruit (Chen et al. 1992). In China, most trees are planted onhills and slopes without artificial irrigation (Fig. 3.1). Annual precipi-tation and its seasonal distribution are the most important factors influ-encing tree growth and fruit production. In Zhejiang, precipitation ofmore than 1000 mm is usually required (Li et al. 1992), and the optimumis between 1300–1700 mm.

Low humidity results in poor pollination and reduced yields. Rain-fall of more than 260 mm during February and April favors the growthof the root system, leaf development, blossoming, and fruit set. Theperiod May to June is of particular importance for fruit maturation,warmth and light being needed to enhance fruit color. Rainfall of morethan 160 mm is required in June, since less than 100 mm will result insmall, poor-quality fruit, and a reduction in yield. Having sunny daysduring late summer to early autumn is beneficial for the accumulationof carbohydrates and flower bud differentiation. Most of the importantcommercial areas of red bayberry production in China do not haveextremes of temperature and humidity.


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C. Soil

A deep, fertile, acid soil with a pH of 4–5.5 is the optimum for cultiva-tion. In mountainous areas, successful growth of plants such as Dicra-nopteris pedata (Houtt.) Nakaike, Rhododendron simsii Planch., pines,firs, bamboos, Cyclobalanopsis glauca (Thunb.) Oerst., Quercus acutis-sima Carruth., or Castanopsis sclerophylla (Lindl.) Schott. indicate suit-able conditions for bayberry cultivation (Li et al. 1992). Red bayberry istolerant of shade and can be planted in less-fertile soils and fine sandyloams. Planting in clay or sandy soils can result in weak and/or dwarfedtrees. The presence of nitrogen-fixing root nodules allows the trees toperform well on infertile but well-drained slopes. In fertile flat soils,trees may have excess vegetative growth and consequently shed flow-ers and fruit. The species is susceptible to boron deficiency, which canresult in small leaf size.

D. Light

Although tolerant of shade, sufficient light is needed for cropping. Ruanand Wu (1991) found that the tree had significant winter photosyntheticrates, although the net rate was usually below 1.5 mg CO2 d–1m–2. Fruitof poor quality and small size may be produced on south-facing slopeswhere direct light and heat is excessive (Li et al. 1992).

E. Elevation and Exposure

Flowering and fruiting have been shown to be delayed by up to 20 dayswith an increase in elevation from 50 to 600 m (Chen et al. 1989). Treesgrown at between 200 and 400 m produce fruit of high quality, with sol-uble solids levels of 9.9–10.1% and acidity 1.8–1.55% (Chen et al. 1992).Elevations greater than 500 m are unsuitable for cultivation since annualtemperatures are usually below 15°C. The trees are not tolerant of strongwinds because of a shallow root system, dense branches and leaves, largecanopy, and brittle shoots.

V. HORTICULTURE

A. Propagation

The most widely used methods for propagation include seeds, grafting,and layering (Wang 1995). Propagation from seed has been the traditionalpractice in many areas in China, especially for rootstocks. Seeds need to


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be stratified, and are generally sown in November. The soil should bedeep, well drained, and with reasonable organic matter. Soils previ-ously used for citrus, peach, pine, cypress and red bayberry itself are usu-ally unsuitable for sowing, probably because of nutrient depletion, withsoils used for annual crops such as rice, vegetables and leguminousplants being preferred. The seeds are sown at a density of about 1.2–1.5kg⋅m–2, and they germinate in the following spring. In April, seedlings canbe transplanted to nurseries when about 7 cm high. By the time of thenext spring after transplanting, the saplings are suitable for grafting.

Seedlings with a stem diameter over 0.5 cm can be used as rootstocksfor grafting. For scions, one- to two-year-old shoots are cut from treesover 10 years old with a history of good yields, and these are cut intoseveral 7-cm segments after removing the leaves. The optimum time forgrafting is between late March and early April in Zhejiang. A survivalrate of over 70% can be achieved with cleft grafting.

The growers in Xiaoshan and Lanxi in Zhejiang province often prop-agate red bayberry by layering, which is usually performed before budbreak in spring. This method speeds up the time to production of afruiting tree. However, the root systems of such plants are often shallow,and the growth weak.

B. Field Cultivation

Red bayberry is a long-lived tree and can remain productive for morethan 30 years (Wang 1995). The optimum time for planting varies withregions. To avoid freezing injury in winter, planting takes place duringlate February to mid-March in Zhejiang, Jiangsu, Hunan, and Jiangxi. Inregions with a relatively warm winter, such as in Guangdong, Fujian,Yunnan, Guizhou, and Sichuan, planting is carried out during earlyOctober to early December or from mid-February to mid-March. Plant-ing density is about 600 trees/ha.

Since the tree is dioecious, it is necessary to interplant staminatetrees, at a frequency of about 1–2% (Wang 1995). Pollen grains are smalland can be carried some distance by wind, and if an orchard has stami-nate plantings nearby, then interplanting is not always necessary.

Organic fertilizer applications are commonly made in October, andgreen manure crops, usually leguminous plants, are often interplantedwith young trees to improve soil structure and provide another source ofincome. For plantings on slopes, mounding up can prevent exposure of roots and promote root growth.

According to Zhang (1999), a tonne of ‘Dongkui’ fruit contains 1.4 kgN, 0.07 kg P, 1.8 kg K, 0.06 kg Ca, and 0.28 kg Mg, with a ratio of N: P:


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K=20:1:26. The nutrient contents of fruit (Table 3.3) are generally lowerthan in many fruit crops, especially levels of P and Ca. Since nodulatedroots supply part of the N requirements of the tree, K is the most impor-tant major nutrient that must be supplied from the soil. Excess P appli-cation can be harmful because of possible boron, zinc, and molybdenumdeficiencies.

The kinds of fertilizers used and application rates are related to plantage and soil nutrient status. For example, at a density of 270 trees/ha,fertilizers applied annually to young trees (5 years old) should contain3.5 kg N, 0.9 kg P, and 3.0 kg K, and for adult trees (12 years old) 9.2–10.6kg N, 2.3 kg P, and 12.3 kg K. Fertilizers should be applied three timesa year: during February or March to promote spring flush growth, blos-soming, and fruit set; late May for promoting fruit development; and afurther application just after harvest.

The trees are upright and will grow too tall if not trained, and the rec-ommended practice throughout China is to create a tree with a lowcanopy and open center (Fig. 3.1). Pruning is carried out in February toMarch (spring) and September to October (autumn). Unwanted branchesare removed or cut back to allow light penetration into the canopy to pro-mote fruit set and increase fruit quality. For example, training of‘Dongkui’ trees involves establishing a trunk with 3–4 primary scaffoldlimbs, with angles between the trunk and the limbs greater than 45°, andthe height of the canopy less than 2.5–3.0 m. Groups of fruiting branches,rather than secondary scaffold limbs, should be allowed to develop onthe main limbs, and these should be replaced by new groups aboutevery 4 years (Wang 1999).


Table 3.3. The content of mineral elements in different organs of red bayberry trees(data from Zhang 1999).

Fruit Nutrient Content (% dry weight)

Tree age Organs N P K Ca Mg

Non-bearing (5 year old) Leaves 1.33 0.08 0.95 0.46 0.14

Shoots 0.31–0.67 0.03–0.04 0.24–0.76 0.12–0.31 0.02–0.08Roots 0.57 0.03 0.53 0.15 0.07

Bearing (12 year old) Leaves 1.27 0.07 1.02 0.38 0.13

Fruit 1.01 0.02 1.10 0.03 0.12Shoots 0.24–0.82 0.02–0.03 0.25–0.08 0.11–0.28 0.02–0.09Roots 0.55 0.03 0.57 0.17 0.06

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Alternate bearing has been the target of recent research. Li et al. (2001)showed that spraying bayberry trees with 250 g/L GA3 in June and Julyinhibited the activities of PAL, POD, and PPO, and hence slowed downthe biosynthesis of lignin, suppressed the differentiation of flower buds,and as a result, greatly reduced flowers in the following year. Theseresults confirm those of Lavee (1989), who found that phenylalanineammonia lyase (PAL), peroxidase (POD), polyphenol oxidase (PPO),and lignin were related to formation of flower buds. GA3 treatment pro-moted the emergence of spring shoots by 133%, increased the size offlower buds on spring shoots, and increased fruit weight by 3.8 g, solu-ble solids by 3.4%, and advanced maturity by 3 days (Liang et al. 2000).Paclobutrazol (PP333), an inhibitor of GA biosynthesis, applied in autumnor spring to arrest the vigorous growth of young trees, accelerates the for-mation of flower buds. However, Luo and Huang (1997) reported thatspraying trees with PP333 at 500 mg/L in spring decreased fruit size andsugar content while increasing acid levels. Trunk spiral girdling alsoeffectively promotes flower formation (Luo et al. 1999).

In China, growing red bayberry in greenhouses was first carried outin Wenzhou, Zhejiang in 1999–2000 with ‘Ding-ao’ (Huang and Zhao2001). The system has proved to be profitable, with fruit in the marketearly in the season realizing higher prices. The plastic house, 20 m ×10 m × 4.5 m, resulted in average temperatures being increased by 4.5°C,humidity by 7.5%, the ripening date being advanced by 14–16 days, andyields being increased by 11.5%. However, the time from fruit set to fullmaturation did not change, remaining at about 106 days.

C. Pests and Diseases

There are important disease and pest problems in red bayberry (listedin Table 3.4), and although studies on these are generally limited, thereis some information available in the literature. Pseudomonas syringaepv. myrigae is one of the most widely distributed pathogens, infecting2- to 3-year-old shoots and resulting in a tumor-like growth known asred bayberry ulcer or sore (Li 2002). Smooth, milky tubercles arise at theinfected sites, and then develop into larger, rough, brown or blacktumors, 1.5–2 cm in diameter. The symptoms become apparent about 30days after infection. The disease develops in late April to May, and pro-tective methods involve removal and burning of infected shoots fol-lowed by a 0.5% Bordeaux spray.

Brown leaf spot results from infection of Mycosphaerella myricaeSaw. The round or irregular spots are 4–8 mm in diameter, with brown


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or greyish-brown borders and reddish-brown or greyish-white centers.The spots can coalesce and may result in leaf wilting and abscission.Control is through use of fungicides such as a 0.5% Bordeaux spray, and70% thiophanate methyl and 50% carbendazol wettable powders,sprayed onto foliage one month before full fruit ripening, two weeksprior to harvest, and after harvest (Li 2002).

Root rot is an important disease in Zhoushan Island of ZhejiangProvince. The pathogen has been identified as Botryosphaeria dothidea(Moung ex Fr.) Ces. & de. Not. (Li et al. 1995), with infection spreadingthrough the root system, resulting in wilting and tree death. Control isthrough soil applications of carbendazol at 0.25–0.5 kg/tree or thio-phanate at 0.25–0.5 kg/tree (Ren et al. 2000).


Table 3.4. Major pathogens and pests of red bayberry (data from Chen 1994; Cai 2000;Rao et al. 2001).

Disease Production or pest Binomial Affected tissue area

DiseaseBrown leaf Mycosphaerella myricae Leaves Zhejiang

spotRoot rot Botryosphaeria dothidea Roots ZhejiangRust Caeoma makinoi Kusano Leaves FujianTumor-like Pseudomonas syringae Shoots, trunk Zhejiang,

growth pv. myricae JapanRed mould Corticium saimonicolor Branches ZhejiangStem blight Myxosporium corticola Trunk All produc-

ing areasShoot rot Valsa coronata Cortex of shoot ZhejiangNematodeRoot-knot Meloidogyne spp. Roots Fujian

InsectLeaf wilt moth Lebeda nobilis Leaves Jiangsu,

Zhejiang, Fujian

Scale insect Lepidosphes cupressi Spring leaves ZhejiangLeaf rolling Homona spp. Young leaves Zhejiang

mothScale insect Fiorinia myricae Fruit JapanFruit fly Drosophila melanogaster Fruit JapanWhite ant Odontotermes formosanus Trunk, root ZhejiangWhite ant Macrotermes barneyi Trunk, root Zhejiang

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Scale insects are common and important pests resulting in severeyield losses and decline in fruit quality; they include Lepidosaphescupressi Borchsenius in Zhejiang and Jiangsu areas of China, and Fior-inia myricae Targioni in Japan (Xu et al. 1995; Mao 2000). Lepidos-aphes cupressi feed on foliage and have two reproductive cycles peryear, egg-laying being in mid-April and late July. Insecticides such asbuprofezin are used for control, in combination with agriculture prac-tices and native predators such as Chilocorus kuwanae Silvestri andProspaltella spp. (Xu et al. 1995).

D. Harvest and Handling

Bayberry fruit are picked when eating ripe. Fruit maturation and time ofripening on the tree varies greatly with growing region. The fruit ripenin early April in Guizhou, from mid- to late May in Fujian, Guangdong,and Sichuan, and from early June to mid-July in Zhejiang, Anhui, Jiangsu,Hunan, and Jiangxi. In most regions, high temperatures and rain are com-mon at the time of fruit ripening, making them susceptible to preharvestdrop and rots, resulting in a comparatively short harvest time (Liu 2000).

Fruit maturation also varies with cultivars, and since unripe fruit areexcessively acid, estimation of maturity and the appropriate harvesttime is important. Flesh color is a useful indicator of ripeness and is usedas a harvest index. For example, color changing from red to purple orblack indicates ripeness for the black type, from bluish green to whitefor the white type, and from green to deep red for the red type. The sol-uble solids contents increase in the fruit with ripening, while total acidlevels decrease. The optimum acid content for harvest is between1–1.2% for ‘Biqi’ fruit (Miao and Wang 1987).

Individual fruit on a tree ripen at different times, and fruit often haveto be picked as frequently as every day. Since the fruit are susceptibleto mechanical injury, careful handling is necessary. The optimum timesfor picking are early morning and evening, when the field heat is least.The flesh is susceptible to damage from pickers, and current recom-mendations are that fruit should be picked with stalk attached, andpacked in 3–5 kg bamboo baskets with leaves or weeds to reduce dam-age. Fruit shaken from the trees can only be used for processing.

E. Storage and Transportation

Red bayberry is a delicate fruit and has a short storage life, made shorterby enhanced flesh softness resulting from high temperatures and rain atharvest. The storage life of the fruit is 9–12 days at 0–2°C, 5–7 days at


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10–12°C, and 3 days at 20–22°C (Xi et al. 1993). There is a need for moreresearch on extending the storage and shelf life of the fruit, particularlyif it is to be used more widely as an export crop.

As the fruit ripens, the total soluble solids (TSS) contents increase andacid levels decrease, resulting in higher ratios of TSS to acids. Sugars arethe main constituents of TSS, and sucrose is the principal sugar, account-ing for about 60% of the total. Citric acid is the predominant acid, withoxalic acid as the next most abundant; acetic and malic acids are minorcomponents. Fruit quality declines rapidly during storage. For example,after storage at 0–2°C for 12 days, fruit TSS decreased by 10.5%, totalacids by 41.4%, sucrose by 49.1%, and vitamin C by 36%, from 432µmol/L to 277 µmol/L (Xi et al. 1993). These decreases can be retardedby treatment with salicylic acid, an inhibitor of plant senescence (Gaoet al. 1989).

Cell membrane permeability, measured by changes in electrical con-ductivity of tissue, increases during fruit storage, and is greater at highertemperatures (Xi et al. 1994). These permeability changes, along withincreased respiration and ethylene production, increase under vibra-tional stress, such as may occur during postharvest handling and trans-port (Ying et al. 1993; Zheng et al. 1996).

There are different views on the respiration pattern of ripening red bay-berry fruit. Xi et al. (1994) classified it as nonclimacteric, whereas Hu etal. (2001) regarded it as climacteric because they detected a small ethyl-ene production peak both at 21°C and 1°C. Ethylene production duringstorage may be dependent on fruit maturity at harvest, since less mature‘Biqi’ fruit (picked at the pink stage) showed some increase in ethyleneproduction after harvest (Fig. 3.7; K. Chen et al., unpublished data).

The activity of superoxide dismutase (SOD), a free radical scavengerand thus a protectant against oxidative stress, gradually increases in thefruit during the first 6 days after harvest, and then decreases rapidly, fol-lowing a pattern familiar in senescing tissues. High storage temperaturesand vibration stress accelerate this decline in SOD activity (Xi et al. 1994;Zheng et al. 1996). The levels of SOD in vibration-stressed fruit were lessthan those in control fruit, supporting the observation that such stresscan promote fruit senescence (Zheng et al. 1996).

Malondiadehyde (MDA), a product of membrane peroxidation, whichitself can further damage membrane structure and function, has been fol-lowed during storage. Fruit stored at 1°C or under high nitrogen (85%)had substantially lower contents of MDA and a longer storage life (Xi etal. 2001). Another group of metabolites, polyamines including spermi-dine, spermine, and putrescine, share the same precursor as ethylene intheir biosynthetic pathway. In a study of vibration stress on bayberry


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fruit, synthesis of spermidine increased whereas ethylene productiondecreased during the initial post-vibration storage period, suggesting apossible protective metabolic system (Zheng et al. 1996). At a later stage,spermine content decreased while ethylene was produced at a higherrate than in control fruit, suggesting that vibrational stress ultimatelyaccelerated the overall senescence process. Putrescine accumulated dur-ing the final storage period, and may be detrimental to fruit storage.

Storage life of the fruit can be extended up to two weeks if fruit arestored at 0–1°C, with a relative humidity of 85–90% (Xiao et al. 1999;Xi et al. 2001). Postharvest treatments such as sodium sorbate, 1% sal-icylic acid, or 0.5% CaCl2 together with 7.5 mg/L NAA (Liu 2000)increased storage life, although 1-MCP (the inhibitor of ethylene recep-tion) had little effect (K. Chen et al., unpublished data). Modified atmos-phere packaging and controlled atmospheres have not been studied toany great extent.


Fig. 3.7. Changes in ethylene production of ‘Biqi’ red bayberry fruit of different matu-rity (K. Chen et al., unpublished data).

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In China, red bayberry is traditionally picked from the tree directlyinto bamboo baskets, and then transported to the market. Because of theincreasing commercial production and value of the crop, packaging ofthe fruit has greatly improved. Fruit are graded by size and color to pro-vide uniform packs. In Yuyao, Zhejiang province, high-quality ‘Biqi’fruit are selected and packed in 500-g plastic boxes, then in 3-kg cartons,and shipped to Hong Kong. ‘Dongkui’ fruit, being larger and of higherquality, are packed 10 to a plastic box. Good results have also beenachieved with other cultivars by changing the number of fruit in a box(Lu et al. 1999). In Japan, red bayberry are packed in 400-g polyethyl-ene bags and then into 1.6-kg wooden or plastic boxes (Miao and Wang1987). Because they are susceptible to rots, fruit should be precooledbefore packing and transported carefully to avoid vibration and hightemperatures.

Since the short storage life limits the period of supply to the market,there are benefits in freezing. Fresh fruit can be blast-frozen at –25 to–30°C for 15 minutes, and then stored and transported at –18°C.

F. Processing

Red bayberry fruit can be processed into jam, juice, wine, or as candiedproducts, and canned red bayberry fruit is exported from China, partic-ularly to Southeast Asian countries. Recent annual production of thecanned product in Zhejiang has reached 1,800 t, about a third of whichis exported.

Ye and Zhang (2000) have shown that the fruit pigments can be usedas food additives, although they are readily affected by pH, ultravioletlight, and reducing agents. Rapid and simple carbon dioxide supercrit-ical extraction technology is needed for pigment extraction. The pig-ments have good potential uses so long as stability can be assured. Juicecan be extracted with 2% saline at 70–80°C, and the preferred productcontains 40% original extract, 10.5% sugar, and 0.45% acid (Zheng andChen 2000). Red bayberry wine is also an important product of the fruit.Relatively high pectin and cellulose contents are largely responsible forthe existence of methanol in the wine, and this needs to be kept at lev-els less than 0.08 mg/100 ml (Huang 1999).

The composition of red bayberry fruit is summarized in Table 3.5. Inaddition, three flavonoids have been isolated from the fruit stone and iden-tified by spectral analysis as quercetin, myricetin, and quercetin-3-O-α-D-glucopyranosyl-(6→1)-α-α-L-rhamnopyranoside (Zou 1995). Thesecompounds, especially quercetin and myricetin, are active antioxidants.


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There are also some unknown compounds in the stones that can arrest thegrowth of cancer cells or induce cell death (Zhang et al. 1993).

VI. CONCLUDING REMARKS

China has a rich genetic resource in red bayberry, with a wide range of cropping and fruit properties that should be exploited for breedingpurposes. Some wild species fruit early, resist high temperature, aredwarfing, and have excellent postharvest properties. Many contain com-pounds of medical importance. These resources are in danger of beingdestroyed; species such as Myrica esculenta Buch are on the edge ofextinction.


Table 3.5. Chemical composition of ripe red bayberry fruit.

Content Component (fresh weight basis) Reference

Total soluble solids 11.6–13.4% Wang et al. 2001Total sugars 9.8–11.7% Wang et al. 2001

Sucrose 46.6 mg/g Zhang et al. 1991Glucose 13.5 mg/g Zhang et al. 1991Fructose 13.8 mg/g Zhang et al. 1991

Total acids 0.42–1.28% Wang et al. 2001Citric acid 0–10.3 mg/g Zhang et al. 1991;

Wang et al. 2001Tartaric acid 1.2–4.5 mg/g Wang et al. 2001Malic acid 1.3–1.7 mg/g Wang et al. 2001Succinic acid 1.2–3.1 mg/g Wang et al. 2001Acetic acid 0.5–2.0 mg/g Wang et al. 2001Oxalic acid 1.9 mg/g Zhang et al. 1991

MineralsPotassium 1.41 mg/g Wang et al. 2001Trace elements (Fe, Mn, Zn, 0.075 mg/g Miao and Wang 1987

Cu, Mg)Vitamins

Vitamin C 0.11–1.14 mg/g Wang et al. 2001(ascorbic acid)

Vitamin B1 0.054 mg/g Wang et al. 2001Vitamin B6 0.008–0.016 mg/g Wang et al. 2001Vitamin E 0.0007–0.0016 mg/g Wang et al. 2001Vitamin A 0.00004–0.0005 mg/g Wang et al. 2001

Protein 0.33% Zhang et al. 1991

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There are 268 cultivars planted in China, of which about two-thirdsripen in mid- to late June (Zhang and Miao 1999). There are some early-maturing cultivars such as ‘Zaoxingmei’ grown in Huangyan and Wen-ling, Zhejiang province, that ripen in May, but the fruit is small and acid.The storage life of almost all cultivars is very limited, resulting in severelosses each season. It is imperative that further breeding work be carriedout to create new early-maturing cultivars of high fruit quality andlonger storage potential.

Only 9.3% of total cultivars are white fleshed (Miao and Wang 1987),and only one, ‘Shuijingyangmei’ or ‘Crystal’, has been commerciallyplanted, in Shangyu, Zhejiang province, its place of origin. There is aneed for more effort in breeding new white-fleshed cultivars adapted todifferent climates.

Alternate bearing has a major impact on production; in years of highyield, the price of fruit may be low, while in low years there may beinsufficient fruit to meet consumer demand. Furthermore, comparedwith other fruit crops, the yield of red bayberry is quite low. This meansthat there is a need to increase yield and reduce cropping variability.

The short storage life, together with other cultivation, harvesting, andhandling problems has inhibited the development of the crop. Red bay-berry is a candidate for international markets provided that storage andshelf life of the fruit can be extended. The crop has potential outside ofChina in warm-temperate and sub-tropical growing conditions. Withcurrent limitations on storage life, production would need to be alignedwith easily accessible markets.

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