HORTICULTURAL CLASSIFICATION OF TEMPERATE FRUITS

 What are Temperate Fruit Plants?

Temperate fruits plants are specific in the climatic requirement.They can tolerate both diurnal and seasonal wide fluctuation of temperature and are grown only in place where winter is distinctly cold.

They require exposure of specific chilling temperature for certain period to break bud dormancy and initiate bud break.

These fruit plants are generally deciduous and suitable of higher elevation as they can withstand frost.Examples are: apple, pear, plum, apricot, almond, peach, strawberry, walnut, pecan nut and cherry.

Horticultural classification of temperate fruits

Classification is a system of placing an individual or a number in various groups, or to categorizes them according to a particular plan or sequence which is in conformity with the nomenclature

Fruit can be classified on several basis but their classification on the basis of climatic adaptability and morphological features seems to be more relevant from the horticulture point of view.

CLASSIFICATION of temperate fruits

1. Classification on the basis of plant stature:

a. Temperate tree fruits: Fruits borne on the trees growing in the temperate climates such as apple, pear, stone fruits etc.

b. Temperate small fruits: Fruits generally borne on the vines, brambles or herbaceous plants grown under temperate climate like strawberry, craneberry, blackberry, blueberry etc.

c. Temperate nuts: Nuts are characterized by the hard shell outside, separating the kernel and husk of the fruit. Pecan nut, hazel nut and walnut are good examples of temperate fruit plants producing nuts.

Classification based on fruit morphology

Depending on number of ovaries involved in fruit formation, fruits are classified into three groups.

(i) simple fruits

(ii) aggregate fruits

( iii) multiple (composite) fruits

i. Simple fruits: Simple fruits are derived from a single ovary of one flower. Simple fruits are further classified as fleshy and dry fruits.

A. Fleshy fruits: These are this fruits whose pericarp (ovary wall) becomes fleshy or succulent at maturity.

The temperate fleshy fruits may be either pome or drupe.

1. Pome: The pome is an inferior, two or more celled fleshy, syncarpous fruit surrounded by the thalamus. The fruit is referred as false fruit as the edible fleshy part is not derived from the ovarian tissues but from external ovarian tissue thalamus. Examples of temperate pome fruits are apple, pear and quince).

Drupe (stone): This type of fruit derived from a single carpel, however, the olive is an exception in that the flower has two carples and four ovules but one carpel develop. Two ovules are borne in most of drupes but one seed develops. In this type of fruit, the pericarp is differentiated into three distinct layers; thin exocarp or peel of the fruits, the mesocarp which is fleshy and hard and stony endocarp, enclosing seed.

Examples of temperate drupe fruits are cherry, peach, plum and apricot. In almond at maturity exocarp and mesocarp get separated as leathery involucre and are removed before

1. marketing, only endocarp containing the edible seed is used hence it is nut

Dry fruits: This type of fruit has been classified on the basis of pericarp (ovary wall) at maturity. The entire pericarp becomes dry and often brittle or hard at maturity.

They are dehiscent ( in which the seeds are dispersed from fruit at maturity) and indehiscent ( not split open when ripe) Nuts are typical example of indehiscent dry fruits

Nut: A fruit in which carpel wall is hard or bony in texture. Fruit is derived from an hypogynous flower ( filbert) or an epigynous one ( walnut) and is enclosed in dry involucres (husk). It is only one seeded, but in most cases in derived from two carpels. Examples are walnut, almond, chestnut, hazelnut and pecan nut.

Dry fruits are not juicy or succulent when mature and ripe. When dry, they may split open and discharge their seeds (called dehiscent fruits) or retain their seeds (called indehiscent fruits).

Achene: A one seeded fruit in which the seed is attached to ovary wall at one point. Example is strawberry.

Aggregate fruits: Aggregate fruits develop from numerous ovaries of the same flower. Individual ovary may be drupe or berry. Raspberry is included in this category

Multiple (composite) fruits: Multiple or composite fruits are produced from the ripened ovaries of several flowers crowded on the same inflorescence. The example of this type is mulberry

Classification based on Fruit Growth Pattern:

Sigmoid pattern:

The combined growth of fruit results from cell division, cell enlargement and air space formation results in sigmoidal ( S- shaped) curve when fruit weight is plotted as function of time. Examples are apple, walnut, pecan, strawberry and pear

Double sigmoid:

The first slow growth period coincides with the period of pit hardening, during which

lignification of the endocarp (stone) proceeds rapidly, while mesocarp and seed growth

suppressed. Near the end of pit hardening, flesh cells enlarge rapidly until fruit is ripe, after

which growth slows down and ceases. Examples are peach, plum, cherry and kiwifruit

Classification based on bearing habit:

The flower bud is either terminal or lateral. Based upon the location of fruit buds and type of flower bearing

structure to which they give rise, the temperate fruits are classified as under.

1. Terminal bearer temperate fruits:

(a) Flower buds mixed, flowering shoot with terminal inflorescences. Examples are apple, pear, walnut (pistillate flowers) and pecan (pistillate flowers)

2. Lateral bearer:

(a) Flower bud containing flower parts only e.g peach, apricot, plum, cherry, almond, walnut ( staminate catkin) and pecan (staminate catkin)

(b) Flower buds mixed, flowering shoot with terminal inflorescences e.g blackberry, raspberry, blueberry