Abstract: ‘Rongza 4’ is a new fat-loofah F₁ hybrid developed by crossing 1621-2-4-3-1-5-12 as female parent and 15-3-7-7-1-8-2-7-3 as male parent. It has strong growth vigor and branching. The first fruit is located at the 7th-10th node of the main stem. The fruit shape is bunched at the waist and nearly cylindric，with small tubercles on the surface. It’s 22.0–29.0 cm in length and 4.0–5.2 cm in width. The average of fruit weight is 285.0–380.0 g and the total yield is 31 239.0–55 217.0 kg · hm^-2.

Key words: loofah, cultivar