Siamese Acidless Pummelo

Siamese Acidless Pummelo, also known as Siamese Sweet (CES 2240), is described as essentially acidless, with oblate to broadly obovoid fruit, a slightly rough yellow rind, and blond flesh. Its fruit has large, crisp, easily separable, low-juice sacs. UCR describes the flavor as insipidly sweet, with a trace of bitterness.^{⁠[1]⁠[3]⁠[5]}

The tree is small or dwarf and drooping, with rounded leaf tips and densely hairy new growth. UCR reports that the fruit matures in winter and holds well on the tree.^⁠[1]

UCR records the U.S. clone as introduced by USDA in 1930 and received at Riverside under Siamese Sweet (CES 2240). Its low acidity has made it useful as a parent in citrus breeding. A 2019 study linked the non-sour P2240 fruit to reduced expression of genes involved in fruit acidification, while leaving the exact causal mutation unresolved.^⁠[1]⁠[5]