'Nam Roi' is an important pummelo cultivar in south Vietnam. Information from the donor describes the fruit as being piriform, necked, with a truncate apex; a slightly adherent, smooth, yellow epircarp averaging 12.7 cm in width; very conspicuous oil glands; and a white mesocarp. The fruit have an average of 12 - 13 segments with slight adherence; a hollow center; tender, white-yellow pulp; large juice vesicles; an average of 22.5 seeds per fruit; and a good flavor. Dr Trinh, who visited from Vietnam 09/11/2000, explained the origin of the name. "Nam" = 5, "Roi" = a blow with a stick. The 'Nam Roi' was a highly prized pummelo growing in the yard of an old man living in a village. Boys would climb the tree and steal pummelos, so the old man threatened them with five blows with a switch if they stole the fruit. But, the pummelos were so good that the boys continued to steal them in spite of teh threat. Of 50 seeds received, 10 germinated. Molecular analysis in the laboratory of Prof Mikeal Roose in 1999 indicated that all the seeds were unique and therefore zygotic. They were planted in the field at the Coachella Valley Agricultural Research Station in Thermal, California, for observation and maintenance. On 01/08/2009, four seedlings were selected and propagated for maintenance under protection: RRUT 417, RRUT 418, RRUT 419, and RRUT 420. The remainder of the seedlings will be maintained for the time being. RRUT 417 was selected from a tree with fruit showing a slight blush. (RR Krueger, 02/28/2009)