Kinnow - Citrus nobilis × Citrus × deliciosa

The kinnow is a high yield mandarin hybrid cultivated extensively in the wider Punjab region of Pakistan and India .

It is a hybrid of two citrus cultivars — 'King' (Citrus nobilis) × 'Willow Leaf' (Citrus × deliciosa) — first developed by Howard B. Frost at the University of California Citrus Experiment Station. After evaluation, the kinnow was released as a new citrus hybrid for commercial cultivation in 1935.

In a hot climate, plants can grow up to 35 feet high. Kinnow trees are highly productive; it is not uncommon to find 1000 fruits per tree. The fruit matures in January or February. It peels easily and has a high juice content.

The high seed content in this variety is a major hindrance in out-of-hand eating. University of California, Riverside, USA developed low seeded Kinnow and released it under the name 'Kinnow LS' in the year 2011.

Punjab Agricultural University, Ludhiana, India also developed low seeded Kinnow through mutation breeding and recommended it under the name 'PAU Kinnow' in the year 2015.

In Pakistan, seedless kinnow has been developed (using selection method) by Niaz Ahmad Chaudhry, a team member of National Agricultural Research Centre (NARC), Islamabad 'NARC' (former director of Citrus Research Institute (CRI), Sargodha,'CRI'. The seedless variety has achieved a higher production level from the Western Mediterranean countries of Spain and Morroco.

Most of the target export markets of the Pakistani kinnow are those of developing countries. Only 2.6 percent of kinnow exports target the markets of developed countries, which is due to the emerging demand for seedless kinnow by the developed countries.

About 61 percent of total world exports of oranges and mandarins are of seedless varieties. Some important export markets for kinnow are: Iran, Bahrain, United Arab Emirates, Kuwait, Oman, Qatar, Saudi Arabia, Indonesia, Malaysia, Afghanistan, Netherlands, Philippines, Singapore, the United Kingdom, Russia and Vietnam.

Indonesia has also offered market access to kinnow, from Pakistan at zero per cent. Over 40% of the Pakistani exports of kinnows went to Russia in 2015.

Kinnow harvesting starts when the fruit's external colour becomes orange, from December to February. The best harvesting time is mid-January to mid-February, when the fruit attains a TSS/acid ratio of 12:1 to 14:1.

The fruit quality declines in later pickings. Fruits are harvested by clipping the stem with the help of sharp clippers (secateurs). The stem is cut as short as possible to avoid mechanical injury to the fruit in packing and transits.

As it is a comparatively loose rind fruit, harvesting by pulling fruits with one's hands is avoided. Coating kinnow fruits with commercial waxes can increase the shelf life up to 60 days. The fruit can be stored in cold storage at a temperature of 4-5 °C and a relative humidity of 85-90%.

Food processing includes the selection of good-quality fruit. The ideal kinnow is firm to slightly soft, smooth-skinned with no deep grooves, and deep orange to almost red. Human hands can better judge and avoid product with soft spots, dull and faded coloring or rough and bumpy skin.

Faisalabad Agricultural University in Faisalabad, Pakistan has developed new technologies for obtaining higher yields of better quality fruits under the conditions of Punjab. These fruits can be stored at room temperature conditions or under cold storage conditions.

Parentage/origins: Reported to be a hybrid between King tangor and Willowleaf mandarin.

Rootstocks of accession: Carrizo citrange, C-35 citrange

Season of ripeness at Riverside: January to March

Kinnow, a King-Willowleaf mandarin hybrid, was developed at the University of California Research Center, Riverside by H. B. Frost in 1915 and released in 1935. Kinnow is the most widely-planted mandarin in Pakistan.

The tree grows vigorously and has an upright form, with a strong tendency to alternate bearing. The fruit is oblate with a smooth orange rind that does not peel especially well for a mandarin. The flesh is orange, seedy, and has a rich distinctive flavor. Kinnow is mid-season in maturity and holds well on the tree.

Fruit medium in size, moderately to slightly oblate; both base and apex flattened or slightly depressed.  Rind thin, rather adherent for a mandarin but peelable, tough and leathery; surface very smooth and glossy, sometimes faintly pitted; color yellowish-orange at maturity.  Segments 9 to 10, firm, separating fairly easily; axis solid to semi-hollow.

Flesh color deep yellowish-orange; very juicy; flavor rich, aromatic, and distinctive.  Seeds numerous, polyembryonic, and cotyledons pale greenish-yellow.  Midseason in maturity (about like Dancy).  Fruit holds well on tree with little puffing.

Tree vigorous and large, tall and columnar, with numerous long, slender, ascending, and virtually thornless branchlets; dense foliage consists of medium-large, broadly lanceolate leaves.  Rather strong tendency to alternate bearing with large crop of smaller fruits followed by very small crop of larger fruits. Cold-resistant.

This high-quality variety is a sister to Wilking, both resulting from a King-Willowleaf (Mediterranean) mandarin cross made in 1915 by H. B. Frost (1935) of the University of California Citrus Research Center, Riverside, California, and named and released in 1935.

Kinnow has been distributed widely and is currently grown commercially to some extent in California, Arizona, West Pakistan, and India (Punjab).  The total plantings in California (mainly the Coachella Valley) and Arizona in 1964 were estimated at 900 acres. "

Availability: Commercially available in California through the Citrus Clonal Protection Program.