The apple tree comes from southern Kazakhstan; Kyrgyzstan; Uzbekistan; Turkey; and the northwestern part of China. Apples have been grown for thousands of years in Asia and in Europe. They were brought to North America by European World Colonial settlers. Apples have Religious and mythological significance in many cultures.
Apples are generally grown by grafting, although wild apples grow readily from seed. Apple trees are normally large if grown from seed, but small if grafted onto roots (rootstock). There are more than 10,000 known variants of apples, with a range of desired characteristics. Different variants are bred for various tastes and uses: cooking, eating raw and cider production are the most common uses. In addition to that, when it comes to food toxicity, the seeds in apples can be fatal, but only if they've been crushed. Apples contain amygdalin, which can release cyanide when digested. Apple seeds contain a chemical that can make cyanide, but the amount is too small to harm people who eat a few seeds.
Trees and fruit are attacked by fungi, bacteria and pests. In 2010, the fruit's genome was sequenced as part of research on disease control and selective breeding in apple production.
Worldwide production of apples in 2013 was 90.8 million tonnes. China grew 49% of the total.