Yes I believe that the Ugli Tangelo does grow true from seed. The Ugli tangelo mother tree was first found growing in 1914 on the island of Jamaica near Brown's Town, and was thought to be a seedling. When Dr. John Webber of the University Of California at Riverside, California began his two year study of the Ugli, he did his research using 13 one year old Ugli seedling trees that he grew from seed sent to him from Jamaica, therefore the fruit must come true from seed. Further it has long been known that most all varieties of tangelos come true from seed. - Millet