Succulent citrus varieties and other fruit trees thrive very well in cold weather.

Of the edible citrus varieties, only the kumquat is more cold-hardy.

Nucellar embryony (notated Nu+) is a form of seed reproduction that occurs in certain plant species, including many citrus varieties.

Because of the uniformity in citrus variety the state has been adversely affected by canker, causing crop and monetary losses.

For a while, it served as the under-stock for grafting commercial citrus varieties.

This also pollinates seeded citrus varieties.

Many citrus varieties are seedless and are produced parthenocarpically without pollination.

A few citrus varieties, including some tangelos and tangerines are self-incompatible, and require cross pollination.

By this method, bees also pollinate seeded citrus varieties.

Strict regulation and management is necessary to control this disease since there are currently no citrus varieties that are resistant.