**5.5 Cultivars**

Fruit color development of apple peel varies greatly with the cultivar. The most colored strains of "Royal Beaut" and "Buckeye Gala" (both semistriped) and "Ruby Gala" (blushed) redden on both fruit sides, with a greater average fruit surface colored, whereas the less colored strains of "Galaxy" and "Mondial Gala" (both striped) exhibit different colorations between sides, more bicolor fruits, and lower average fruit surface colored [17]. Furthermore, the reddest strains ("Royal Beaut," "Buckeye Gala," "Ruby Gala," etc.) have high coloring potential even at the early stages of fruit development or under environmental conditions associated with hot temperatures or with low-light conditions such as the shaded parts of tree canopy. However, in medium or poorly colored strains ("Galaxy," "Mondial Gala," etc.), color development depends mainly on fruit maturity. The genotype is therefore one of the main factors determining the degree of redness in apple fruits, and this provides important information on how to make the best use of apple in breeding.
