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Pecan

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The pecan (Carya illinoinensis) is a large deciduous tree native to the Mississippi River region. This area includes the southern United States and northern Mexico. The pecan is a member of the Juglandaceae family. This family includes more than 60 species of plants. Most of these species live in the Northern Hemisphere of the New World. The pecan is highly valued for its edible seed. This seed is used in many snacks and desserts. It is the state nut of Alabama, Arkansas, California, Louisiana, and Texas. Texas even recognizes the pecan as its state tree.

Pecan sprouting
Pecan sprouting

Understanding how a pecan grows requires looking at its unique structure. While many people call it a nut, it is technically a drupe. A drupe is a fruit that has a single stone or pit surrounded by a husk. The husk is formed from the exocarp tissue of the flower. The part we eat, the seed, develops from the endocarp. The husk is oval or oblong in shape. It starts out green and has a brassy, greenish-gold color. As the fruit matures, the husk turns brown. At this stage, the thick husk splits into four sections. This process releases the thin-shelled seed from the fruit.

Pecan hulls burst open revealing fruit
Pecan hulls burst open revealing fruit

The history of the pecan involves deep evolutionary changes. The first fossils of the Juglandaceae family appeared during the Cretaceous period. About 64 million years ago, during the early Paleogene, different subfamilies began to separate. The Engelhardioideae subfamily is generally tropical and evergreen. In contrast, the Juglandioideae subfamily is deciduous and lives in temperate zones. A major step for the pecan was a change in how it spreads seeds. It moved from wind-dispersed fruits to animal dispersion. This change happened as the tree developed a husk. It also involved a change in fatty acids. The ratio of oleic to linoleic acids actually inverted during this transition.

Humans have interacted with pecans for a very long time. Native Americans knew wild pecans as a delicacy. They may have even helped the trees spread by planting them. However, commercial growing in the United States did not begin until the 1880s. There was even a debate about how to say the word "pecan." In 1927, the National Pecan Growers Association set an official rule. They requested that everyone use the pronunciation "pea-con."

Pecan halves with centimeter scale
Pecan halves with centimeter scale

Today, pecan production is a massive global industry. In 2014, the United States produced an annual crop of 300,000 metric tons. About 75% of this crop comes from Georgia, New Mexico, and Texas. In 2017, Mexico produced nearly half of the world's total pecans. This volume was similar to the production in the United States. Together, these two countries account for 93% of global production. South Africa has also become a major player. As of 2024, it is the third largest producer and exports mostly to China.

Growing pecans successfully is a complex task for farmers. Pecan trees need long, hot, and humid summers to thrive. They also require large amounts of water. Many orchards use flood irrigation to help the trees grow. Farmers must also manage pollination carefully. Most varieties require two or more different cultivars to pollinate each other. Growers look at the Alternate Bearing Index, or ABI. This index describes how likely a tree is to produce crops every other year. They also group trees by their pollination timing. Some are protandrous, meaning they shed pollen before receiving it. Others are protogynous, meaning they shed pollen after they are receptive.

Maintaining a healthy pecan orchard involves fighting many challenges. Diseases like pecan scab can be very destructive. This is especially true in humid conditions. Farmers often use fungicides to prevent this. Insects also pose a threat to the leaves and stems. Many different types of bugs feed on the trees, including weevils and aphids. Sometimes, the trees suffer from nutrient deficiencies. For example, a lack of nickel can cause a disorder called "mouse-ear." A lack of zinc can cause the leaves to grow in a crowded pattern called rosetting.

PecanPie
PecanPie

Despite these challenges, the rewards of the pecan are great. The seeds are rich in nutrients and flavor. A single serving of 28 grams provides 690 calories. It is a very high source of manganese and thiamine. The seed is also composed of 72% fat and 9% protein. People use pecans in many delicious ways. They are a main ingredient in pecan pie and praline candy. You can also find them in cookies and ice cream. Beyond food, the wood is very useful. It is used to make furniture and flooring. It is also used as fuel to smoke meats, adding a sweet flavor.

Pecan halves with centimeter scale
Pecan halves with centimeter scale
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File:Pecan hulls burst open revealing fruit.jpg
Pecan hulls burst open revealing fruit.jpg
File:Pecan sprouting.jpg
Pecan sprouting.jpg
File:Pecan halves with centimeter scale.jpg
Pecan halves with centimeter scale.jpg
File:PecanPie.JPG
PecanPie.JPG
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