Advances in Food Research pp. 349, 351 (2014)
The Chemical Constituents of Citrus Fruits
J. F. Kefford

3. Effect of Rootstock

The rate of disappearance of the limonoid bitter principles with maturity is greatly influenced by the rootstock on which the scion variety is grafted. Marsh (1953), working in California, observed that bitterness disappeared early in the season from Navel oranges grown on grapefruit and trifoliate orange stocks, late in the season from fruit on stocks of sweet and sour oranges and Navel cutting, and not at all from fruit on rough lemon stock. Similar observations were made in Australia by Kefford et al. (1952). Navel oranges from trifoliate orange, tangelo, and Cleopatra mandarin stocks gave the least bitter juices; fruit from sweet orange, East Indian lime, and sweet lime stocks gave juices intermediate in bitterness; and juices from fruit on Kusaie lime and rough lemon stocks were most bitter. Even juices from Valencia oranges on rough lemon stocks were bitter up to an advanced stage of maturity. Determinations of the amounts of crude bitter principle in the peels of these fruits showed parallel trends (Chandler, 1958b). Thus, no bitter principle could be recovered from the peel of Navel and Valencia oranges on trifoliate orange stocks, while Navels on rough lemon stock yielded 0.03 to 0.10% bitter principle on a dry basis, and Valencias on rough lemon stock yielded O to 0.07%, the highest contents being found in the least mature fruits.

Stock/Scion Influence