Citrus Plant Origins and Evolution
– Citrus plants are native to subtropical and tropical regions of Asia, Island Southeast Asia, Near Oceania, and northeastern and central Australia.
– Genomic analysis suggests the center of origin of the genus Citrus is likely the southeast foothills of the Himalayas.
– Citrus species spread into Taiwan and Japan in the Early Pliocene.
– Citrus fruit evolved from small berries over millions of years.
– Citrus species diverged from a common ancestor about 15 million years ago.
– Ancestral species associated with modern Citrus cultivars are the mandarin orange, pomelo, and citron.
– Citrus first evolved in the foothills of the Himalayas, according to a DNA study.
– Most commercially important citrus fruits are hybrids involving mandarin orange, pomelo, and citron.
– Fossil leaf specimens of Citrus meletensis have been found in Italy, and Citrus linczangensis in China.
– The taxonomy and systematics of the Citrus genus are complex due to many named species being hybrids.
Citrus Fruit Production and Cultivation
– Citrus production was 124 million metric tons in 2016.
– Citrus trade makes up nearly half of the world fruit trade.
– Oranges were the most produced citrus fruit in 2019–20.
– Major producers include Brazil, Mexico, the EU, and China.
– Citrus trees are not frost hardy, except mandarin oranges.
– Trees need a sunny, humid environment with fertile soil.
– Fruit ripens in fall or early winter, depending on the cultivar.
– Some citrus varieties take up to 18 months to ripen.
– Most commercial cultivation uses grafted trees for desired fruit.
– Citrus trees are evergreen and do not drop leaves except under stress.
Citrus Fruit Culinary and Health Uses
– Citrus fruits like oranges, tangerines, grapefruits are commonly eaten fresh.
– Lemon and lime juices are used in cooking and beverages.
– Citrus zest is used for flavoring in cooking.
– Marmalade is made from cooked orange or lemon.
– Citrus fruits are used as garnishes in drinks and dishes.
– Consumption of citrus fruits is linked to a 10% reduced breast cancer risk.
– Citrus fruits are rich in vitamin C and flavonoids.
– Adding acidic fertilizer can revive citrus plants experiencing chlorosis deficiency.
– Citrus prefers neutral soil pH, and excessive salt in soil harms citrus plants.
Citrus Fruit Pests, Diseases, and Deficiency
– Citrus canker caused by Xanthomonas axonopodis.
– Citrus plants are prone to infestation by aphids, whitefly, and scale insects.
– Citrus tristeza virus is transmitted by aphids.
– Asian citrus psyllid carries Huanglongbing disease.
– Citrus greening disease is devastating to citrus groves.
– Citrus plants can develop chlorosis deficiency due to high pH preventing nutrient absorption.
– Proper soil testing is important to diagnose nutrient-deficiency diseases.
– Excessive salt in soil harms citrus plants.
Citrus Fruit Varieties and Hybrids
– Descendants of mandarins have low furanocoumarins, while hybrids like limes and grapefruits have high furanocoumarins.
– Citrus peel contains more furanocoumarins than pulp.
– Citron varieties include Alemow, Colo, Buddhas hand, and others with varying pulp characteristics.
– Lemon varieties include Ponderosa, Key lime, Persian lime, and others.
– Other citrus varieties include Calamansi, Calamondin, Blood orange, Chinotto, and more.
– Sweetie is a pomelo-grapefruit hybrid, and Clementines have thinner skins compared to oranges.
– Citrus hybrids like Tangelo, Tangor, Sweet oranges, and others are widely used in various foods.