In general grouping, it has been accepted that citrus falls into one of four classifications:
1. The Oranges
2. The Mandarins
3. The Grapefruits & Pummelos
4. The acid group:
Today, with new genetic ans molecular biological techniques, the conclusion has been drawn that there are three true species in the genus Citrus (the citron, the mandarin and the pummelo). Oranges, lemons, limes and grapefruit, although disseminated throughout the world by men in both ancient and modern times, each have a narrow genetic base
For our own, and the consumers' understanding, all of the above belong to the genus Citrus. In addition, we note the distantly related trifoliate orange, Poncirus trifoliate, which is significant as a rootstock in commercial plantings, and the genus Fortunella, more commonly known as kumquats.
The botanical characteristics of the leaves, flowers, fruits, and seeds are usually sufficiently consistent for identification of the group. However, the Horticultural characteristics are extremely variable and many lack in the constancy that result in numerous citrus fruit varieties that are indistinguishable within each group without further investigation.
Climate factors can have a remarkable effect on citrus. For example the large-fruited Washington navel orange, renowned world-wide as the finest fruit for hand-held consumption, attains the ideal size when grown in California but will become undesirably large when grown in the humid, semitropical climates of Florida or Brazil. Conversely, the small-fruited Hamlin orange of Florida and Brazil will never attain a commercially acceptable size when grown in the arid and cooler climate of the southern California coastal region.
Climate also affects the shape of the fruit: certain citrus varieties grown in low humidity will cause the extension of the axis making the fruit oblong instead of round. Mandarins can develop a “neck” and grapefruit will reach an elongated shape referred to as a “sheep nose”.
Fruit color of most citrus is markedly affected by climate during the ripening period. Maximum color intensity is achieved when the fruit is subject to chilling, normally as a result of cold nights, and subsequent wide diurnal fluctuations of warming temperatures. Citrus in tropical areas may never obtain the color change with the possible exception of the Dancy tangerine.
Other fruit characteristics materially affected by atmospheric humidity during the growing season include rind surface, thickness, texture and adherence, and texture of the flesh of the fruit and juice content. Flavor is also markedly affected by mostly the same climatic factors. The natural sugar and acids in citrus and the ratios of the two determine the intensity of flavor. Mostly the arid, semitropical climates produce stronger richer flavors than the semitropical and tropical areas. The reverse can be true with some high acidic varieties such as kumquats and some mandarins as well as the bitterness of most grapefruit.
Rootstock Effects and Soil Influences
To a lesser degree but nonetheless a variable factor, rootstock and the soil where the trees are planted, including the amount of water received, also affect the characteristics of the fruit. Soil differences are usually small but can be accentuated by rootstock. For example, the undesirable influences of the rough lemon rootstock are increased by sandy soils and reduced slightly by silty soils.
Personal Preference: Beauty is in the eye of the beholder
In the case of citrus, taste preferences for certain varieties is as varied as the many selections available within the general groupings. Although certain characteristics are documented for each variety, where and how that variety has been grown and under what particular set of climatic and agricultural conditions, will ultimately determine each consumer’s definition of their favorite citrus variety.
VARIETAL DEFINITIONS AND MODES OF ORIGIN
This definition of variety is from Howard B. Frost, a pioneer in citrus breeding and genetics whose 40 years of services at the University of California provided much of our current basic knowledge of citrus genetic behavior, reads:
Irrespective of mode of origin and method of reproduction or multiplication, a horticultural variety (cultivar) consists of a named or otherwise designated group of plants representing one of the many genetically different kinds of any given cultivated plant species or botanical variety.
In citrus, as with most other fruits, a horticultural variety traces back to a single parent tree or individual mutant branch, now called a ‘clone’. Citrus varieties or cultivars are therefore clonal varieties.
Foregoing the thousands of pages of research on citrus clonal varieties, we will highlight the properties of several varieties we offer to our customers with a bit of insight we have accumulated from either growing them ourselves or being directly involved in their production.
“We have neglected the truth that a good farmer is a craftsman of
the highest order, a kind of artist.”