|MadSci Network: Botany|
Cultivated apples are often classified as a hybrid species, Malus X domestica. 'Gala', 'Red Delicious', 'Fuji' and 'Macintosh' are different apple varieties or cultivars (cultivated varieties). The basic flower structure, and therefore fruit structure, is the same regardless of apple cultivar. Each apple fruit has five seed compartments (called carpels). Each carpel can contain a maximum of two seeds, for a maximum of ten seeds per apple fruit. One exception seems to be 'Northern Spy' apple, which may produce up to four seeds per carpel and up to twenty per fruit. Some cultivars, such as 'Jonagold', are reported to often have just three or four seeds. 'Jonagold' is a triploid which is probably the reason for its low seed set. You might want to check seed number in 'Jonagold' and other triploid cultivars, such as 'Rhode Island Greenings', 'Mutsu' or 'Crispin', 'Baldwin', 'Stayman Winesap', 'Belle de Boskoop', 'Blenheim Orange', 'Bramley', 'Gravenstein', 'Ribston', 'Jupiter' and 'Reinette dí Angleterre'. Some apples have less than the potential maximum number of seeds due to incomplete pollination, fertilization failure, or because fertilized eggs fail to develop into normal or "full" seeds. Seeds that fail to develop properly are often flat. Apple fruits with few seeds are often reduced in size or lopsided so apple growers typically have bee hives in orchards to assure good pollination. If you examined many fruit of one apple cultivar, you would probably find some variation in seed number. References Malus domestica (Domestic Apple) The Science of Apples & How They're Grown 'Jonagold' seed number Fruit Size and Fruit Quality Pollination and Honey Bees Lopsided Apple Photo Flat seeds influence apple fruit quality Effective Apple Pollination List of Triploid Apples
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