A trillion is 109 or 1,000,000,000. See also: Billion. Triploid
A plant that has three sets of chromosomes in place of the usual two. Triploids are usually sterile, and they are difficult to breed (e.g., banana). Tristeza
'Tristeza' means sadness in Spanish, and this is the name of a virus disease of citrus, also known as 'stem pitting'. The diagnostic symptom is a flattening of the branches and, when the bark is peeled off, there are pits in the wood, with corresponding projections in the bark. Diseased trees usually die, following severe dieback. Tristeza is a graft incompatibility disease, and it is serious mainly on trees grafted on to sour orange rootstocks. Resistant scion-stock combinations have rootstocks of sweet orange, rough lemon, and 'Cleopatra mandarin'. Triticale
A modern inter-generic hybrid between wheat and rye. It has not proved particularly successful as the uses for its grain are limited.
Was this article helpful?