An international research team has successfully mapped the "fully phased" genome of the Fuji apple, delineating the genetic inheritance from both parent strains. This comprehensive genetic map has enabled the examination of 74 Fuji apple clones, revealing a range of somatic mutations. These mutations, which are not inherited but rather occur during the plant's lifetime, are responsible for distinct characteristics such as early ripening and spur-type growth.
The Fuji apple, a hybrid of the Red Delicious and Ralls Janet varieties, was developed in 1979 and is celebrated for its sweet taste and crunchy texture. The study pinpointed the MdTCP11 gene, which functions as a regulator of growth, noting that compact apple trees exhibit a minor deletion near this gene. This deletion amplifies the gene's activity, leading to shorter branches and a denser tree form. Additionally, the research highlighted a difference in DNA methylation levels between spur-type and standard apple varieties. Reduced methylation in spur types allows for increased activity of MdTCP11, promoting the development of spur characteristics.
Source: ISAAA