DESCRIPTION AND USE OF LOQUAT

G. Llácer, M.L. Badenes and J. Martínez-Calvo

Instituto Valenciano de Investigaciones Agrarias

Valencia, Spain

BOTANICAL SPECIES: Eriobotrya japonica (Thunb.) Lindl.

FAMILY: Rosaceae

HABITAT. The center of origin of E. japonica species is been accepted to be the middle and lower valley of the Daduhe river in China (18). From there was spread to Japan and later in the 18th century to the botanical gardens of Paris and Naples through Mauricio Island (14). The Loquat was adapted very well to the Mediterranean basin, same areas where citrus crop can be grown (11). Loquat is cultivated mainly in China, Japan, India, Pakistan, Madagascar, Reunion Island, Mauricio Island, Mediterranean countries (Spain, Turkey, Italy, Greece, Israel), United States (mainly California and Florida), Brazil, Venezuela, and Australia, always in tight environmental conditions. Since flowering and fruit set occurs during winter, Loquat requires humid and warm climate. Optimum average temperature should be upper than 15ºC. It stands no freezes or winds. Preferred orchard orientation is Southeast or South (North Hemisphere) and height lower than 400 m. The degree of cold injury to reproductive organs increase with development, being the highest in immature fruits. It can be grown without irrigation when rainfall is higher than 1200 m. Sandy clay soils, deep and well drained, are the most convenient (pH ranging from 6 to 8). Loquat roots are sensitive to asphyxia and salinity. A better adaptation to different soil types can be reached by using alternative rootstocks to Loquat seedlings, as quince, pear or hawthorn. However these rootstocks are not used very often due to scion/rootstock compatibility (14).

GENETIC VARIABILITY. In origin, 2 types of Loquat could be distinguished: a) Chinese type, characterized by large fruits, pear-shaped and yellow-flesh; b) Japanese type, characterized by small fruits, round-shaped and white or pale-yellow-flesh (2). From these types, a large number of varieties emerged in different countries where Loquat was grown. Very often, current varieties are selected as seedling variations resulting from natural hybridization (6). Fourteen species of the genus Eriobotrya and more than 100 varieties of E. japonica have been described in China (5,6,18). Recently, several studies have described characteristics of promising cultivars obtained by selection or breeding in China (9), India (16), Brazil (1) and Italy (13). New varieties obtained by radiation breeding has been reported in China (19). Isozyme analysis for cultivar differentiation were described in Israel (4). In Spain, a study of 35 varieties showed a great variability in important traits as flowering and harvest season, fertility, fruit weight, maturity index and number of seeds per fruit (7). Most varieties are considered self-compatible, however some studies recommend the introduction of honeybee colonies to Loquat orchards to improve fruit set and yield (10).

PLANT. Loquat plant is a small tree that usually is not higher than 5 or 6 m, with persistent leaves, rounded crown, straight trunk, rough and gray bark that peels-off yearly. The root system in a Loquat seedling grows close to the surface (25-30 cm deep). The annual cycle has three growing seasons: spring, summer and fall shoots. Flower bud differentiation occurs in July-August, flower bud formation occurs in September-October, flowering season extends from November to February, depending on the cultivar, and harvest season extends from March to June (data referred to North Hemisphere) (14,17). Plants grafted on seedlings have a first harvest at the second growth year and a regular yield could be reached at fifth year in a well managed orchard. The period of regular cropping is about 25 to 30 years (which is shorter when grafted on quince rootstock) (14).

LEAVES. Loquat leaves are large or very large (18-40 cm long), lance-shaped, serrated and leathery, short petiole, pronounced central nerve, rough and green upper face, the lower face is cotton-like and grey. Other leave characteristics that allow to distinguish varieties are: shape of tip (acute or obtuse), density of serrations (sparse or dense), attachment to shoot (upwards, horizontal or downwards) and color of upper face (pale or dark green) (14,17).

FLOWERS. Flowers are clustered and located at the tip of the central shoots and sometimes at lateral shoots. Flowers are small, white or yellowish and scented. Each flower have 5 united sepals, 5 petals, 20 stamens and 5 pistils whose ovary is attached to the calyx. Usually, there are 60-70 flowers per cluster. The main characteristics that distinguish clusters are: size, shape (conical or cylindrical), number of flowers and position of flowers (upwards, horizontal or downwards) (14,17).

FRUITS. Loquat fruit is a pome type with 1 to 5 seeds (pips) grouped at the center of fruit. Fruits are small (average weight in thinned trees ranges from 30 to 55 g, varieties with higher average weight are rare), rounded, elliptic, egg-shaped or pear-shaped; skin color ranges from pale yellow to bright orange, flesh color ranges from white to orange including all different gradation of yellows. The seeds are large with brown seed-coat. Other fruit characteristics that allow to distinguish varieties are: shape of stalk end (acute, obtuse or round), calyx cavity (open or closed), shape of apex (concave, flat or convex), peeling from stalk end (easy or difficult), thickness of flesh and number, size and shape of seeds (14,17). The development of seedless fruits has been studied in Taiwan (8).

USES. Historically, Loquat species was an ornamental tree with small fruits and as ornamental was spread from Japan to Europe in 18th century. Later, in 19th century, since selections of cultivars with larger fruits were available, the fruits were used by consumers. However it is still used for landscaping (12). Nowadays most of the production is for fresh market. Loquat fruits have a melting and refreshing flesh, aromatic, sweet and sour. They are also consumed in syrup, jams and spirits (2,14). Leaves of Loquat are used in various countries to treat skin diseases and diabetes (3). Unifloral Loquat honey is very appreciated in Sicily (Italy) (15).

Morphological data on Loquat tree accessions from IVIA

Distance matrix and dendrogram on Loquat from IVIA