According to Official Guinness Records,
The heaviest pummelo/pomelo weighs 4,859.7 g (10 lb 11.3 oz) and was grown by Kumamoto Prefectural Yatsushiro Agricultural High School (Japan) in Yatsushiro, Kumamoto, Japan. The weight was verified on 25 December 2014. The specimen was a Japanese pomelo called Banpeiyu (Citrus grandis/maxima). The school grows Banpeiyu as a teaching material, and one of them had grown so big the school decided to apply for the record. The title-holding pomelo had a diameter of 28.1 cm (11.06 in).
For a complete list of 2014 records, please visit 2014 Guinness Records in Japan.