Cultivation of Quinces: Exploring the History, Taxonomy, and Pomological Classification

Quince cultivation has a rich history rooted in regions such as northwestern Iran, northern Caucasus, around the Caspian Sea, and northern Anatolia. While wild quince extends as far as Turkestan in the east and southern regions of Europe and North Africa in the west, its cultivation dates back to ancient times. Initially introduced from Anatolia, quince culture spread to Greece and Rome in the years before Christ. Historical records indicate that it was cultivated in Greece around 650 BC, later spreading to central and eastern Europe. Today, quince is grown in all countries except Australia, yet its demand and production remain limited compared to other fruits.

Understanding the Taxonomy and Genetics of Quinces

Quinces, scientifically known as Cydonia vulgaris Pers., belong to the Rosales order, Rosaceae family, and Pomoide subfamily. Within the Cydonia genus, there are two other notable species, Cydonia sinensis Thouin and Cydonia japonica Pers., mainly recognized for ornamental purposes in Turkey. Cydonia vulgaris further divides into two botanical varieties: C. vulgaris maliformis, encompassing apple-shaped cultivars, and C. vulgaris piriformis, which includes pear-shaped varieties. However, the diversity of cultivated quince varieties is not as extensive as that of apples and pears due to factors such as limited cultural importance, insufficient focus on selective breeding, and a lower occurrence of natural hybridization.

Pomological Classification of Quinces: Exploring Apple and Pear-Shaped Varieties

Quinces have traditionally been classified into two groups based on fruit shape:

1. Quinces with apple-shaped fruits (var. maliformis)
2. Quinces with pear-shaped fruits (var. piriformis)

The majority of our quince varieties, including Limon, Demir, Ekmek, and Bardak, fall into the second group, characterized by pear-shaped fruits.

Quince Varieties: Characteristics and Regional Significance

• Bardak Quince: Primarily cultivated in the Kocaeli region, Bardak quince is often found interspersed among vineyards, alongside cherries. The fruits are densely hairy, with crisp, juicy, and slightly acidic flesh. Harvested in late September, they are commonly used to make “hevenk” and can be stored in the cellar for an extended period. The tree is mostly single-stemmed, moderately sized (3-4 m), and productive.
• Demir Quince: Distinguished by its round fruits, smaller than those of Ekmek quince, Demir quince has firm, juicy, non-astringent flesh. The fruits, which ripen in October, are greenish-yellow, smooth, and glossy. The tree, initially upright, tends to branch downward as it bears fruit.
• Ekmek Quince: This variety has several types, differing in taste and size. The main Ekmek quinces are prized for both table and kitchen use, featuring large, showy fruits with a narrow stem end, broad bottom, yellow skin, light fuzz, and thick, crisp, juicy, and slightly acidic flesh. Harvested in late September in the Kocaeli region, these fruits can be stored until February. The tree grows to a medium size, with sparse branching and good productivity.
• Limon Quince: Sought after in the market, Limon quinces have round fruits with a lengthening toward the stem end. The skin is lemon-yellow, fuzzy, and thick, while the flesh is yellowish, crisp, very juicy, and slightly acidic. Harvested in late September, these fruits can be stored until December. The tree develops to a medium size, initially growing upright but branching downward as it ages.
• Eşme Quince: Cultivation of Eşme quince has become widespread in the Marmara region in recent years. The fruits are medium to large, round, broad at the bottom, and tapering towards the stem. The flesh is crisp, juicy, slightly acidic, and non-astringent. These quinces, with high table value, can be stored until February-March under suitable conditions.

Morphological and Biological Traits of Quinces

Morphology

• Habit: Quince trees have a shrub-like form, reaching a height of 6-8 m when single-stemmed. The trunk is short, and the roots are shallow and fibrous.
• Branches: Unlike apples and pears, quinces lack specialized fruit branches. Young branches are densely fuzzy and yellow-green, while older branches are sparsely fuzzy and brownish-green.
• Buds: Quince buds are small, fuzzy, and covered with a few scales. The flower buds are mixed, forming both shoots and flowers at the tips of fruit spurs. Each bud gives rise to a flower, while shoot buds produce only new branches.
• Leaves: Quince leaves are egg-shaped or broadly elliptical, dark green with toothless margins. Young leaves have winged petioles.
• Flowers: Rosaceae-type flowers consist of 5 sepals and 5 petals. Sepals persist on the fruit. Petals are pink-white or white. There are 15-20 stamens and a 5-carpelled ovary.
• Fruit: Quinces belong to the pome fruit group, similar to apples and pears. The fruit is large, often with slight fuzziness on the surface. The flesh can be either firm or crisp, juicy, and pleasantly fragrant. The seeds, numerous and sticky, are shaped like inverted eggs and extend to the surface of the fruit.

Pollination Biology

Most cultivated quince varieties are considered self-fertile, allowing the establishment of orchards with a single variety. The chromosome number is n=17, and triploids have not been observed in this species.

Ecological Requirements of Quinces

Climate Requirements

Quinces thrive best in a temperate maritime climate. However, quince cultivation is also encountered in regions far from the maritime climate, such as the inland provinces of Central Anatolia. In these areas, successful cultivation is often restricted to suitable orientations and valleys. Quince trees in Turkey display a level of cold resistance comparable to that of apples and pears, with less demand for winter chill hours. Due to the late formation of flowers at the tips of the shoots growing in the same year, quinces tend to bloom late in cold regions. In warmer climates, they blossom concurrently with plums. Quinces do not fare well in windy locations, where branches may break, and excessive fruit drop can occur. Both leaves and fruits are susceptible to sclerotinia (white mold), and excessive rainfall can jeopardize the crop.

Soil Requirements

Quinces thrive in well-drained, sandy-loam soils with a warm texture. Since quince roots are shallow and do not penetrate deeply, soil depth is not crucial, but it should never be associated with suffocating moisture conditions. In cold and damp soils, fruits take on a woody texture, diminishing in quality. While quinces can be grown in dry sandy soils when hawthorn is used as a rootstock, growth is generally weak and yields are low under such conditions.

Cultivation Techniques for Quinces: Propagation, Orchard Establishment, and Annual Maintenance

Propagation and Rootstocks

Although quince varieties can be propagated by seeds due to their autogamous nature, the cultural importance of this fruit and its ease of vegetative propagation make methods like cuttings, root suckers, or occasionally grafting more common. In cases requiring grafting, dormant bud grafting is preferred. While quince trees grow well on quince rootstocks, their growth is slow and weak when grown on hawthorn rootstocks, particularly with a noticeable swelling at the graft site.

Orchard Establishment

Quince orchards are rare worldwide, and in our country, there are only a few examples, such as those around Lake Sapanca in Eşme and İzmir. When establishing quince orchards, trees are planted at intervals of 3-4 m with a generally square planting pattern, emphasizing single-stemmed growth.

Annual Maintenance in Quince Orchards

• Soil Cultivation: When cultivating the soil in quince orchards, it is essential to avoid deep plowing. Quince roots are shallow, and deep plowing may damage them significantly. Cultivating the soil once in spring and once in early summer is generally sufficient. Planting a cover crop after cultivation is highly beneficial. In mixed orchards, soil cultivation is tailored to the primary fruit, with no significant challenges when planting alongside apples or pears.
• Irrigation: In quince orchards in regions with dry summers, such as Central Anatolia, irrigation is essential. Depending on the water availability, irrigation is repeated every 15-20 days. Orchards without access to water can only be established in areas with sufficient rainfall that is well-distributed.
• Fertilization: Quince roots, being shallow, rely on the nutrients available in the topsoil. Therefore, efforts should be made to keep this part of the soil nutrient-rich. Applying three to four tons of farmyard manure every three to four years during rotation is highly beneficial. Additionally, nitrogenous fertilizers provide valuable support.
• Pruning: Quince trees naturally form a well-structured canopy, and proper initial crown formation reduces the need for excessive pruning in subsequent years. The ideal crown shape for quinces is a goblet. The trunk is kept low, and the upward growth of the canopy is limited by removing excessive terminal shoots. However, care should be taken not to prune excessively during terminal shoot removal, as fruit formation primarily occurs on shoot tips. Over-pruning may result in a tree devoid of fruit.

Fruit Handling and Storage of Quinces

Harvesting

Quinces reach maturity when the fruit skin starts transitioning from green to yellow, particularly evident in fuzzy varieties where this fuzz rubs off easily. Early-harvested fruits tend to be dry, tasteless, and astringent. Harvesting is done manually using scissors or a knife, cutting the fruit from the stem junction. Special attention must be given to avoid bruising the fruits during harvesting, as the seemingly tough exterior can be easily damaged. Quince fruits may appear resilient to pressure, but they are easily bruised, with damaged areas turning dark and beginning to rot. Therefore, careful handling is crucial during both harvesting and subsequent handling.

Storage of Quinces in Cold Storage

After harvesting, quinces can be stored in cold storage for 2-3 months. The optimal storage temperature is around 1.5°C, with an ideal relative humidity of 75-80%. Quinces should not be stored together with other fruits during this period, as their strong scent may affect the flavors of other fruits.

In conclusion, quince cultivation involves understanding its historical significance, taxonomy, pomological characteristics, and ecological requirements. Proper techniques in propagation, orchard establishment, and annual maintenance contribute to successful quince cultivation. Careful handling and storage are crucial for preserving the quality of quince fruits after harvest. By embracing these practices, quince growers can enhance the productivity and quality of their orchards.